Funding, Deals & Partnerships: BIOLOGICS & MEDICAL DEVICES; BioMed e-Series; Medicine and Life Sciences Scientific Journal – http://PharmaceuticalIntelligence.com
Eight Subcellular Pathologies driving Chronic Metabolic Diseases – Methods for Mapping Bioelectronic Adjustable Measurements as potential new Therapeutics: Impact on Pharmaceuticals in Use
In this curation we wish to present two breaking through goals:
Goal 1:
Exposition of a new direction of research leading to a more comprehensive understanding of Metabolic Dysfunctional Diseases that are implicated in effecting the emergence of the two leading causes of human mortality in the World in 2023: (a) Cardiovascular Diseases, and (b) Cancer
Goal 2:
Development of Methods for Mapping Bioelectronic Adjustable Measurements as potential new Therapeutics for these eight subcellular causes of chronic metabolic diseases. It is anticipated that it will have a potential impact on the future of Pharmaceuticals to be used, a change from the present time current treatment protocols for Metabolic Dysfunctional Diseases.
According to Dr. Robert Lustig, M.D, an American pediatric endocrinologist. He is Professor emeritus of Pediatrics in the Division of Endocrinology at the University of California, San Francisco, where he specialized in neuroendocrinology and childhood obesity, there are eight subcellular pathologies that drive chronic metabolic diseases.
These eight subcellular pathologies can’t be measured at present time.
In this curation we will attempt to explore methods of measurement for each of these eight pathologies by harnessing the promise of the emerging field known as Bioelectronics.
Unmeasurable eight subcellular pathologies that drive chronic metabolic diseases
Glycation
Oxidative Stress
Mitochondrial dysfunction [beta-oxidation Ac CoA malonyl fatty acid]
Insulin resistance/sensitive [more important than BMI], known as a driver to cancer development
Membrane instability
Inflammation in the gut [mucin layer and tight junctions]
Epigenetics/Methylation
Autophagy [AMPKbeta1 improvement in health span]
Diseases that are not Diseases: no drugs for them, only diet modification will help
Image source
Robert Lustig, M.D. on the Subcellular Processes That Belie Chronic Disease
These eight Subcellular Pathologies driving Chronic Metabolic Diseases are becoming our focus for exploration of the promise of Bioelectronics for two pursuits:
Will Bioelectronics be deemed helpful in measurement of each of the eight pathological processes that underlie and that drive the chronic metabolic syndrome(s) and disease(s)?
IF we will be able to suggest new measurements to currently unmeasurable health harming processes THEN we will attempt to conceptualize new therapeutic targets and new modalities for therapeutics delivery – WE ARE HOPEFUL
In the Bioelecronics domain we are inspired by the work of the following three research sources:
Michael Levin is an American developmental and synthetic biologist at Tufts University, where he is the Vannevar Bush Distinguished Professor. Levin is a director of the Allen Discovery Center at Tufts University and Tufts Center for Regenerative and Developmental Biology. Wikipedia
THE VOICE of Dr. Justin D. Pearlman, MD, PhD, FACC
PENDING
THE VOICE of Stephen J. Williams, PhD
Ten TakeAway Points of Dr. Lustig’s talk on role of diet on the incidence of Type II Diabetes
25% of US children have fatty liver
Type II diabetes can be manifested from fatty live with 151 million people worldwide affected moving up to 568 million in 7 years
A common myth is diabetes due to overweight condition driving the metabolic disease
There is a trend of ‘lean’ diabetes or diabetes in lean people, therefore body mass index not a reliable biomarker for risk for diabetes
Thirty percent of ‘obese’ people just have high subcutaneous fat. the visceral fat is more problematic
there are people who are ‘fat’ but insulin sensitive while have growth hormone receptor defects. Points to other issues related to metabolic state other than insulin and potentially the insulin like growth factors
At any BMI some patients are insulin sensitive while some resistant
Visceral fat accumulation may be more due to chronic stress condition
Fructose can decrease liver mitochondrial function
A methionine and choline deficient diet can lead to rapid NASH development
RNA from the SARS-CoV-2 virus taking over the cells it infects: Virulence – Pathogen’s ability to infect a Resistant Host: The Imbalance between Controlling Virus Replication versus Activation of the Adaptive Immune Response
Curator: Aviva Lev-Ari, PhD, RN – I added colors and bold face
UPDATED on 9/8/2020
What bats can teach us about developing immunity to Covid-19 | Free to read
Another duality and paradox in the Treatment of COVID-19 Patients in ICUs was expressed by Mike Yoffe, MD, PhD, David H. Koch Professor of Biology and Biological Engineering, Massachusetts Institute of Technology. Dr. Yaffe has a joint appointment in Acute Care Surgery, Trauma, and Surgical Critical Care, and in Surgical Oncology @BIDMC
on 6/29 at SOLUTIONS with/in/sight at Koch Institute @MIT
How Are Cancer Researchers Fighting COVID-19? (Part II)”Jun 29, 2020 11:30 AM EST
In COVID-19 patients: two life threatening conditions are seen in ICUs:
Blood Clotting – Hypercoagulability or Thrombophilia
Cytokine Storm – immuno-inflammatory response
The coexistence of 1 and 2 – HINDERS the ability to use effectively tPA as an anti-clotting agent while the cytokine storm is present.
Mike Yoffe’s related domain of expertise:
Signaling pathways and networks that control cytokine responses and inflammation
Misregulation of cytokine feedback loops, along with inappropriate activation of the blood clotting cascade causes dysregulation of cell signaling pathways in innate immune cells (neutrophils and macrophages), resulting in tissue damage and multiple organ failure following trauma or sepsis. Our research is focused on understanding the role of the p38-MK2 pathway in cytokine control and innate immune function, and on cross-talk between cytokines, clotting factors, and neutrophil NADPH oxidase-derived ROS in tissue damage, coagulopathy, and inflammation, using biochemistry, cell biology, and mouse knock-out/knock-in models. We recently discovered a particularly important link between abnormal blood clotting and the complement pathway cytokine C5a which causes excessive production of extracellular ROS and organ damage by neutrophils after traumatic injury.
SARS-CoV-2 infection induces low IFN-I and -III levels with a moderate ISG response
Strong chemokine expression is consistent across in vitro, ex vivo, and in vivo models
Low innate antiviral defenses and high pro-inflammatory cues contribute to COVID-19
Summary
Viral pandemics, such as the one caused by SARS-CoV-2, pose an imminent threat to humanity. Because of its recent emergence, there is a paucity of information regarding viral behavior and host response following SARS-CoV-2 infection. Here we offer an in-depth analysis of the transcriptional response to SARS-CoV-2 compared with other respiratory viruses. Cell and animal models of SARS-CoV-2 infection, in addition to transcriptional and serum profiling of COVID-19 patients, consistently revealed a unique and inappropriate inflammatory response. This response is defined by low levels of type I and III interferons juxtaposed to elevated chemokines and high expression of IL-6. We propose that reduced innate antiviral defenses coupled with exuberant inflammatory cytokine production are the defining and driving features of COVID-19.
Defining the Transcriptional Response to SARS-CoV-2 Relative to Other Respiratory Viruses
To compare the transcriptional response of SARS-CoV-2 with other respiratory viruses, including MERS-CoV, SARS-CoV-1, human parainfluenza virus 3 (HPIV3), respiratory syncytial virus (RSV), and IAV, we first chose to focus on infection in a variety of respiratory cell lines (Figure 1). To this end, we collected poly(A) RNA from infected cells and performed RNA sequencing (RNA-seq) to estimate viral load. These data show that virus infection levels ranged from 0.1% to more than 50% of total RNA reads (Figure 1A).
Discussion
In the present study, we focus on defining the host response to SARS-CoV-2 and other human respiratory viruses in cell lines, primary cell cultures, ferrets, and COVID-19 patients. In general, our data show that the overall transcriptional footprint of SARS-CoV-2 infection was distinct in comparison with other highly pathogenic coronaviruses and common respiratory viruses such as IAV, HPIV3, and RSV. It is noteworthy that, despite a reduced IFN-I and -III response to SARS-CoV-2, we observed a consistent chemokine signature. One exception to this observation is the response to high-MOI infection in A549-ACE2 and Calu-3 cells, where replication was robust and an IFN-I and -III signature could be observed. In both of these examples, cells were infected at a rate to theoretically deliver two functional virions per cell in addition to any defective interfering particles within the virus stock that were not accounted for by plaque assays. Under these conditions, the threshold for PAMP may be achieved prior to the ability of the virus to evade detection through production of a viral antagonist. Alternatively, addition of multiple genomes to a single cell may disrupt the stoichiometry of viral components, which, in turn, may itself generate PAMPs that would not form otherwise. These ideas are supported by the fact that, at a low-MOI infection in A549-ACE2 cells, high levels of replication could also be achieved, but in the absence of IFN-I and -III induction. Taken together, these data suggest that, at low MOIs, the virus is not a strong inducer of the IFN-I and -III system, as opposed to conditions where the MOI is high.
Taken together, the data presented here suggest that the response to SARS-CoV-2 is imbalanced with regard to controlling virus replication versus activation of the adaptive immune response. Given this dynamic, treatments for COVID-19 have less to do with the IFN response and more to do with controlling inflammation. Because our data suggest that numerous chemokines and ILs are elevated in COVID-19 patients, future efforts should focus on U.S. Food and Drug Administration (FDA)-approved drugs that can be rapidly deployed and have immunomodulating properties.
One of the features distinguishing SARS-CoV-2 from its more pathogenic counterpart SARS-CoV is the presence of premature stop codons in its ORF3b gene. Here, we show that SARS-CoV-2 ORF3b is a potent interferon antagonist, suppressing the induction of type I interferon more efficiently than its SARS-CoV ortholog. Phylogenetic analyses and functional assays revealed that SARS-CoV-2-related viruses from bats and pangolins also encode truncated ORF3b gene products with strong anti-interferon activity. Furthermore, analyses of more than 15,000 SARS-CoV-2 sequences identified a natural variant, in which a longer ORF3b reading frame was reconstituted. This variant was isolated from two patients with severe disease and further increased theability of ORF3b to suppress interferon induction. Thus, our findings not only help to explain the poor interferon response in COVID-19 patients, but also describe a possibility of the emergence of natural SARS-CoV-2 quasi-species with extended ORF3b that may exacerbate COVID-19 symptoms.
Highlights
ORF3b of SARS-CoV-2 and related bat and pangolin viruses is a potent IFN antagonist
SARS-CoV-2 ORF3b suppresses IFN induction more efficiently than SARS-CoV ortholog
The anti-IFN activity of ORF3b depends on the length of its C-terminus
An ORF3b with increased IFN antagonism was isolated from two severe COVID-19 cases
RNA (in green) from the SARS-CoV-2 virus is shown taking over the cells it infects.ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
A deep dive into how the new coronavirus infects cells has found that it orchestrates a hostile takeover of their genes unlike any other known viruses do, producing what one leading scientist calls “unique” and “aberrant” changes.Recent studies show that in seizing control of genes in the human cells it invades, the virus changes how segments of DNA are read, doing so in a way that might explain why the elderly are more likely to die of Covid-19 and why antiviral drugs might not only save sick patients’ lives but also prevent severe disease if taken before infection.“It’s something I have never seen in my 20 years of” studying viruses, said virologist Benjamin tenOever of the Icahn School of Medicine at Mount Sinai, referring to how SARS-CoV-2, the virus that causes Covid-19, hijacks cells’ genomes.The “something” he and his colleagues saw is how SARS-CoV-2 blocks one virus-fighting set of genes but allows another set to launch, a pattern never seen with other viruses. Influenza and the original SARS virus (in the early 2000s), for instance, interfere with both arms of the body’s immune response — what tenOever dubs “call to arms” genes and “call for reinforcement” genes.The first group of genes produces interferons. These proteins, which infected cells release, are biological semaphores, signaling to neighboring cells to activate some 500 of their own genes that will slow down the virus’ ability to make millions of copies of itself if it invades them. This lasts seven to 10 days, tenOever said, controlling virus replication and thereby buying time for the second group of genes to act.This second set of genes produce their own secreted proteins, called chemokines, that emit a biochemical “come here!” alarm. When far-flung antibody-making B cells and virus-killing T cells sense the alarm, they race to its source. If all goes well, the first set of genes holds the virus at bay long enough for the lethal professional killers to arrive and start eradicating viruses.
“Most other viruses interfere with some aspect of both the call to arms and the call for reinforcements,” tenOever said. “If they didn’t, no one would ever get a viral illness”: The one-two punch would pummel any incipient infection into submission.
SARS-CoV-2, however, uniquely blocks one cellular defense but activates the other, he and his colleagues reported in a study published last week in Cell. They studied healthy human lung cells growing in lab dishes, ferrets (which the virus infects easily), and lung cells from Covid-19 patients. In all three, they found that within three days of infection, the virus induces cells’ call-for-reinforcement genes to produce cytokines. But it blocks their call-to-arms genes — the interferons that dampen the virus’ replication.
The result is essentially no brakes on the virus’s replication, but a storm of inflammatory molecules in the lungs, which is what tenOever calls an “unique” and “aberrant” consequence of how SARS-CoV-2 manipulates the genome of its target.
In another new study, scientists in Japan last week identified how SARS-CoV-2 accomplishes that genetic manipulation. Its ORF3b gene produces a protein called a transcription factor that has “strong anti-interferon activity,” Kei Sato of the University of Tokyo and colleagues found — stronger than the original SARS virus or influenza viruses. The protein basically blocks the cell from recognizing that a virus is present, in a way that prevents interferon genes from being expressed.
In fact, the Icahn School team found no interferons in the lung cells of Covid-19 patients. Without interferons, tenOever said, “there is nothing to stop the virus from replicating and festering in the lungs forever.”
That causes lung cells to emit even more “call-for-reinforcement” genes, summoning more and more immune cells. Now the lungs have macrophages and neutrophils and other immune cells “everywhere,” tenOever said, causing such runaway inflammation “that you start having inflammation that induces more inflammation.”
At the same time, unchecked viral replication kills lung cells involved in oxygen exchange. “And suddenly you’re in the hospital in severe respiratory distress,” he said.
In elderly people, as well as those with diabetes, heart disease, and other underlying conditions, the call-to-arms part of the immune system is weaker than in younger, healthier people, even before the coronavirus arrives. That reduces even further the cells’ ability to knock down virus replication with interferons, and imbalances the immune system toward the dangerous inflammatory response.
The discovery that SARS-CoV-2 strongly suppresses infected cells’ production of interferons has raised an intriguing possibility: that taking interferons might prevent severe Covid-19 or even prevent it in the first place, said Vineet Menachery of the University of Texas Medical Branch.
In a study of human cells growing in lab dishes, described in a preprint (not peer-reviewed or published in a journal yet), he and his colleagues also found that SARS-CoV-2 “prevents the vast amount” of interferon genes from turning on. But when cells growing in lab dishes received the interferon IFN-1 before exposure to the coronavirus, “the virus has a difficult time replicating.”
After a few days, the amount of virus in infected but interferon-treated cells was 1,000- to 10,000-fold lower than in infected cells not pre-treated with interferon. (The original SARS virus, in contrast, is insensitive to interferon.)
Ending the pandemic and preventing its return is assumed to require an effective vaccine to prevent infectionand antiviral drugs such as remdesivir to treat the very sick, but the genetic studies suggest a third strategy: preventive drugs.
It’s possible that treatment with so-called type-1 interferon “could stop the virus before it could get established,” Menachery said.
Giving drugs to healthy people is always a dicey proposition, since all drugs have side effects — something considered less acceptable than when a drug is used to treat an illness. “Interferon treatment is rife with complications,” Menachery warned. The various interferons, which are prescribed for hepatitis, cancers, and many other diseases, can cause flu-like symptoms.
But the risk-benefit equation might shift, both for individuals and for society, if interferons or antivirals or other medications are shown to reduce the risk of developing serious Covid-19 or even make any infection nearly asymptomatic.
Interferon “would be warning the cells the virus is coming,” Menachery said, so such pretreatment might “allow treated cells to fend off the virus better and limit its spread.” Determining that will of course require clinical trials, which are underway.
Other related articles in this Open Access Online Scientific Journal include the following:
Structure-guided Drug Discovery: (1) The Coronavirus 3CL hydrolase (Mpro) enzyme (main protease) essential for proteolytic maturation of the virus and (2) viral protease, the RNA polymerase, the viral spike protein, a viral RNA as promising two targets for discovery of cleavage inhibitors of the viral spike polyprotein preventing the Coronavirus Virion the spread of infection
Predicting the Protein Structure of Coronavirus: Inhibition of Nsp15 can slow viral replication and Cryo-EM – Spike protein structure (experimentally verified) vs AI-predicted protein structures (not experimentally verified) of DeepMind (Parent: Google) aka AlphaFold
Curators: Stephen J. Williams, PhD and Aviva Lev-Ari, PhD, RN
Glycobiology vs Proteomics: Glycobiologists Prespective in the effort to explain the origin, etiology and potential therapeutics for the Coronavirus Pandemic (COVID-19).
Actemra, immunosuppressive which was designed to treat rheumatoid arthritis but also approved in 2017 to treat cytokine storms in cancer patients SAVED the sickest of all COVID-19 patients
The Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) Partnership on May 18, 2020: Leadership of AbbVie, Amgen, AstraZeneca, Bristol Myers Squibb, Eisai, Eli Lilly, Evotec, Gilead, GlaxoSmithKline, Johnson & Johnson, KSQ Therapeutics, Merck, Novartis, Pfizer, Roche, Sanofi, Takeda, and Vir. We also thank multiple NIH institutes (especially NIAID), the FDA, BARDA, CDC, the European Medicines Agency, the Department of Defense, the VA, and the Foundation for NIH
Tweets & Retweets 2020 World Medical Innovation Forum – COVID-19, AI and the Future of Medicine, Featuring Harvard and Industry Leader Insights – MGH & BWH, Virtual Event: Monday, May 11, 8:15 a.m. – 5:15 p.m. ET
Actemra, immunosuppressive which was designed to treat rheumatoid arthritis but also approved in 2017 to treat cytokine storms in cancer patients SAVED the sickest of all COVID-19 patients
Reporter: Aviva Lev-Ari, PhD, RN
Emergency room doctor, near death with coronavirus, saved with experimental treatment
Soon after being admitted to his own hospital with a fever, cough and difficulty breathing, he was placed on a ventilator. Five days after that, his lungs and kidneys were failing, his heart was in trouble, and doctors figured he had a day or so to live.
He owes his survival to an elite team of doctors who tried an experimental treatment pioneered in China and used on the sickest of all COVID-19 patients.
Lessons from his dramatic recovery could help doctors worldwide treat other extremely ill COVID-19 patients.
Based on the astronomical level of inflammation in his body and reports written by Chinese and Italian physicians who had treated the sickest COVID-19 patients, the doctors came to believe that it was not the disease itself killing him but his own immune system.
It had gone haywire and began to attack itself — a syndrome known as a “cytokine storm.”
The immune system normally uses proteins called cytokines as weapons in fighting a disease. For unknown reasons in some COVID-19 patients, the immune system first fails to respond quickly enough and then floods the body with cytokines, destroying blood vessels and filling the lungs with fluid.
Dr. Matt Hartman, a cardiologist, said that after four days on the immunosuppressive drug, supplemented by high-dose vitamin C and other therapies, the level of oxygen in Padgett’s blood improved dramatically. On March 23, doctors were able to take him off life support.
Four days later, they removed his breathing tube. He slowly came out of his sedated coma, at first imagining that he was in the top floor of the Space Needle converted to a COVID ward.
4.1.8 Newly Found Functions of B Cell, Volume 2 (Volume Two: Latest in Genomics Methodologies for Therapeutics: Gene Editing, NGS and BioInformatics, Simulations and the Genome Ontology), Part 4: Single Cell Genomics
The importance of B cells to human health is more than what is already known. Vaccines capable of eradicating disease activate B cells, cancer checkpoint blockade therapies are produced using B cells, and B cell deficiencies have devastating impacts. B cells have been a subject of fascination since at least the 1800s. The notion of a humoral branch to immunity emerged from the work of and contemporaries studying B cells in the early 1900s.
Efforts to understand how we could make antibodies from B cells against almost any foreign surface while usually avoiding making them against self, led to Burnet’s clonal selection theory. This was followed by the molecular definition of how a diversity of immunoglobulins can arise by gene rearrangement in developing B cells. Recombination activating gene (RAG)-dependent processes of V-(D)-J rearrangement of immunoglobulin (Ig) gene segments in developing B cells are now known to be able to generate an enormous amount of antibody diversity (theoretically at least 1016 possible variants).
With so much already known, B cell biology might be considered ‘‘done’’ with only incremental advances still to be made, but instead, there is great activity in the field today with numerous major challenges that remain. For example, efforts are underway to develop vaccines that induce broadly neutralizing antibody responses, to understand how autoantigen- and allergen-reactive antibodies arise, and to harness B cell-depletion therapies to correct non-autoantibody-mediated diseases, making it evident that there is still an enormous amount we do not know about B cells and much work to be done.
Multiple self-tolerance checkpoints exist to remove autoreactive specificities from the B cell repertoire or to limit the ability of such cells to secrete autoantigen-binding antibody. These include receptor editing and deletion in immature B cells, competitive elimination of chronically autoantigen binding B cells in the periphery, and a state of anergy that disfavors PC (plasma cell) differentiation. Autoantibody production can occur due to failures in these checkpoints or in T cell self-tolerance mechanisms. Variants in multiple genes are implicated in increasing the likelihood of checkpoint failure and of autoantibody production occurring.
Autoantibodies are pathogenic in a number of human diseases including SLE (Systemic lupus erythematosus), pemphigus vulgaris, Grave’s disease, and myasthenia gravis. B cell depletion therapy using anti-CD20 antibody has been protective in some of these diseases such as pemphigus vulgaris, but not others such as SLE and this appears to reflect the contribution of SLPC (Short lived plasma cells) versus LLPC (Long lived plasma cells) to autoantibody production and the inability of even prolonged anti-CD20 treatment to eliminate the later. These clinical findings have added to the importance of understanding what factors drive SLPC versus LLPC development and what the requirements are to support LLPCs.
B cell depletion therapy has also been efficacious in several other autoimmune diseases, including multiple sclerosis (MS), type 1 diabetes, and rheumatoid arthritis (RA). While the potential contributions of autoantibodies to the pathology of these diseases are still being explored, autoantigen presentation has been posited as another mechanism for B cell disease-promoting activity.
In addition to autoimmunity, B cells play an important role in allergic diseases. IgE antibodies specific for allergen components sensitize mast cells and basophils for rapid degranulation in response to allergen exposures at various sites, such as in the intestine (food allergy), nose (allergic rhinitis), and lung (allergic asthma). IgE production may thus be favored under conditions that induce weak B cell responses and minimal GC (Germinal center) activity, thereby enabling IgE+ B cells and/or PCs to avoid being outcompeted by IgG+ cells. Aside from IgE antibodies, B cells may also contribute to allergic inflammation through their interactions with T cells.
B cells have also emerged as an important source of the immunosuppressive cytokine IL-10. Mouse studies revealed that B cell-derived IL-10 can promote recovery from EAE (Experimental autoimmune encephalomyelitis) and can be protective in models of RA and type 1 diabetes. Moreover, IL-10 production from B cells restrains T cell responses during some viral and bacterial infections. These findings indicate that the influence of B cells on the cytokine milieu will be context dependent.
The presence of B cells in a variety of solid tumor types, including breast cancer, ovarian cancer, and melanoma, has been associated in some studies with a positive prognosis. The mechanism involved is unclear but could include antigen presentation to CD4 and CD8 T cells, antibody production and subsequent enhancement of presentation, or by promoting tertiary lymphoid tissue formation and local T cell accumulation. It is also noteworthy that B cells frequently make antibody responses to cancer antigens and this has led to efforts to use antibodies from cancer patients as biomarkers of disease and to identify immunotherapy targets.
Malignancies of B cells themselves are a common form of hematopoietic cancer. This predilection arises because the gene modifications that B cells undergo during development and in immune responses are not perfect in their fidelity, and antibody responses require extensive B cell proliferation. The study of B cell lymphomas and their associated genetic derangements continues to be illuminating about requirements for normal B cell differentiation and signaling while also leading to the development of targeted therapies.
Overall this study attempted to capture some of the advances in the understanding of B cell biology that have occurred since the turn of the century. These include important steps forward in understanding how B cells encounter antigens, the co-stimulatory and cytokine requirements for their proliferation and differentiation, and how properties of the B cell receptor, the antigen, and helper T cells influence B cell responses. Many advances continue to transform the field including the impact of deep sequencing technologies on understanding B cell repertoires, the IgA-inducing microbiome, and the genetic defects in humans that compromise or exaggerate B cell responses or give rise to B cell malignancies.
Other advances that are providing insight include:
single-cell approaches to define B cell heterogeneity,
glycomic approaches to study effector sugars on antibodies,
new methods to study human B cell responses including CRISPR-based manipulation, and
the use of systems biology to study changes at the whole organism level.
With the recognition that B cells and antibodies are involved in most types of immune response and the realization that inflammatory processes contribute to a wider range of diseases than previously believed, including, for example, metabolic syndrome and neurodegeneration, it is expected that further
basic research-driven discovery about B cell biology will lead to more and improved approaches to maintain health and fight disease in the future.
TWEETS by @pharma_BI and @AVIVA1950 at #IESYMPOSIUM – @kochinstitute 2019 #Immune #Engineering #Symposium, 1/28/2019 – 1/29/2019
Real Time Press Coverage: Aviva Lev-Ari, PhD, RN
2.1.3.4 TWEETS by @pharma_BI and @AVIVA1950 at #IESYMPOSIUM – @kochinstitute 2019 #Immune #Engineering #Symposium, 1/28/2019 – 1/29/2019, Volume 2 (Volume Two: Latest in Genomics Methodologies for Therapeutics: Gene Editing, NGS and BioInformatics, Simulations and the Genome Ontology), Part 2: CRISPR for Gene Editing and DNA Repair
eProceedings for Day 1 and Day 2
LIVE Day One – Koch Institute 2019 Immune Engineering Symposium, January 28, 2019, Kresge Auditorium, MIT
#IESYMPOSIUM@pharma_BI@AVIVA1950 Aviv Regev @kochinstitute Melanoma: malignant cells with resistance in cold niches in situ cells express the resistance program pre-treatment: resistance UP – cold Predict checkpoint immunotherapy outcomes CDK4/6 abemaciclib in cell lines
#IESYMPOSIUM@pharma_BI@AVIVA1950 Diane Mathis @HMS Age-dependent Treg and mSC changes – Linear with increase in age Sex-dependent Treg and mSC changes – Female Treg loss in cases of Obesity leading to fibrosis Treg keep IL-33-Producing mSCs under rein Lean tissue/Obese tissue
#IESYMPOSIUM@pharma_BI@AVIVA1950 Martin LaFleur @HMS Loss of Ptpn2 enhances CD8+ T cell responses to LCMV and Tumors PTpn2 deletion in the immune system enhanced tumor immunity CHIME enables in vivo screening
#IESYMPOSIUM@pharma_BI@AVIVA1950 Alex Shalek @MIT@kochinstitute Identifying and rationally modulating cellular drivers of enhanced immunity T Cells, Clusters Expression of Peak and Memory Immunotherapy- Identifying Dendritic cells enhanced in HIV-1 Elite Controllers
#IESYMPOSIUM@pharma_BI@AVIVA1950 Glenn Dranoff @Novartis Adenosine level in blood or tissue very difficult to measure in blood even more than in tissue – NIR178 + PDR 001 Monotherapy (NIR178) combine with PD receptor blockage (PDR) show benefit A alone vs A+B in Clinical trial
#IESYMPOSIUM@pharma_BI@AVIVA1950 Glenn Dranoff @Novartis PD-L1 blockade elicits responses in some patients: soft part sarcoma LAG-3 combined with PD-1 – human peripheral blood tumor TIM-3 key regulator of T cell and Myeloid cell function: correlates in the TCGA DB myeloid
#IESYMPOSIUM@pharma_BI@AVIVA1950 Yvonne Chen @UCLA Activation of t Cell use CAR t Engineer CAR-T to respond to soluble form of antigens: CD19 CAR Responds to soluble CD19 GFP MCAR responds to Dimeric GFP “Tumor microenvironment is a scary place”
#IESYMPOSIUM@pharma_BI@AVIVA1950 Yvonne Chen @UCLA “Engineering smarter and stronger T cells for cancer immunotherapy” OR-Gate cause no relapse – Probing limits of modularity in CAR Design Bispecific CARs are superior to DualCAR: One vs DualCAR (some remained single CAR)
Ending the 1st session is Cathy Wu of @DanaFarber detailing some amazing work on vaccination strategies for melanoma and glioblastoma patients. They use long peptides engineered from tumor sequencing data. #iesymposium
Some fancy imaging: Duggan gives a nice demo of how dSTORM imaging works using a micropatterend image of Kennedy Institute for Rheumatology! yay! #iesymposium
Lots of interesting talks in the second session of the #iesymposium – effects of lymphoangiogenesis on anti-tumor immune responses, nanoparticle based strategies to improve bNAbs titers/affinity for HIV therapy, and IAPi cancer immunotherapy
Looking forward to another day of the #iesymposium. One more highlight from yesterday – @nm0min from our own lab showcased her work developing cytokine fusions that bind to collagen, boosting efficacy while drastically reducing toxicities
#IESYMPOSIUM@pharma_BI@AVIVA1950 Preeti Sharma, U Illinois T cell receptor and CAR-T engineering TCR engineering for Targeting glycosylated cancer antigens Nornal glycosylation vs Aberrant Engineering 237-CARs libraries with conjugated (Tn-OTS8) against Tn-antigend In vitro
#IESYMPOSIUM@pharma_BI@AVIVA1950 Bryan Bryson @MIT Loss of polarization potential: scRNAseq reveals transcriptional differences Thioredoxin facilitates immune response to Mtb is a marker of an inflammatory macrophage state functional spectrum of human microphages
#IESYMPOSIUM@pharma_BI@AVIVA1950 Bryan Bryson @MIT macrophage axis in Mycobacterium tuberculosis Building “libraries” – surface marker analysis of Microphages Polarized macrophages are functionally different quant and qual differences History of GM-CSF suppresses IL-10
#IESYMPOSIUM@pharma_BI@AVIVA1950 Jamie Spangler John Hopkins University “Reprogramming anti-cancer immunity RESPONSE through molecular engineering” De novo IL-2 potetiator in therapeutic superior to the natural cytokine by molecular engineering mimicking other cytokines
#IESYMPOSIUM@pharma_BI@AVIVA1950 Michael Dustin @UniofOxford ESCRT pathway associated with synaptic ectosomes Locatization, Microscopy Cytotoxic T cell granules CTLs release extracellular vescicles similar to T Helper with perforin and granzyme – CTL vesicles kill targets
#IESYMPOSIUM@pharma_BI@AVIVA1950 Michael Dustin @Oxford Delivery of T cell Effector function through extracellular vesicles Synaptic ectosome biogenisis Model: T cells: DOpamine cascade in germinal cell delivered to synaptic cleft – Effector CD40 – Transfer is cooperative
#IESYMPOSIUM@pharma_BI@AVIVA1950 Michael Dustin @Oxford Delivery of T cell Effector function through extracellular vesicles Laterally mobile ligands track receptor interaction ICAM-1 Signaling of synapse – Sustain signaling by transient in microclusters TCR related Invadipodia
#IESYMPOSIUM@pharma_BI@AVIVA1950 Mikael Pittet @MGH Myeloid Cells in Cancer Indirect mechanism AFTER a-PD-1 Treatment IFN-gamma Sensing Fosters IL-12 & therapeutic Responses aPD-1-Mediated Activation of Tumor Immunity – Direct activation and the ‘Licensing’ Model
#IESYMPOSIUM@pharma_BI@AVIVA1950 Stefani Spranger @MIT KI Response to checkpoint blockade Non-T cell-inflamed – is LACK OF T CELL INFILTRATION Tumor CD103 dendritic cells – Tumor-residing Batf3-drivenCD103 Tumor-intrinsic Beta-catenin mediates lack of T cell infiltration
#IESYMPOSIUM@pharma_BI@AVIVA1950 Max Krummel @UCSF Gene expression association between two genes: #NK and #cDC1 numbers are tightly linked to response to checkpoint blockage IMMUNE “ACCOMODATION” ARCHYTYPES: MYELOID TUNING OF ARCHITYPES Myeloid function and composition
#IESYMPOSIUM@pharma_BI@AVIVA1950 Noor Momin, MIT Lumican-cytokines improve control of distant lesions – Lumican-fusion potentiates systemic anti-tumor immunity
#IESYMPOSIUM@pharma_BI@AVIVA1950 Noor Momin, MIT Lumican fusion to IL-2 improves treatment efficacy reduce toxicity – Anti-TAA mAb – TA99 vs IL-2 Best efficacy and least toxicity in Lumican-MSA-IL-2 vs MSA-IL2 Lumican synergy with CAR-T
excited to attend the @kochinstitute@MIT immune engineering symposium #iesymposium this week! find me there to chat about @CellCellPress and whether your paper could be a good fit for us!
April Pawluk added,
Koch Institute at MITVerified account@kochinstitute
Join leading immunology researchers at our Immune Engineering Symposium on Jan. 28 & 29. Register now: http://bit.ly/2AOUWH6#iesymposium
Bob Schreiber and Tyler Jacks kicked off the #iesymposium with 2 great talks on the role of Class I and Class II neo-Ag in tumor immunogenicity and how the tumor microenvironment alters T cell responsiveness to tumors in vivo
Scott Wilson from @UChicago gave a fantastic talk on glycopolymer conjugation to antigens to improve trafficking to HAPCs and enhanced tolerization in autoimmunity models. Excited to learn more about his work at his @MITChemE faculty talk! #iesymposium
Spending the (literal) first day of my fellowship at the @kochinstitute#iesymposium! @DanaFarber Cathy Wu talking about the use of neoantigen targeting cancer vaccines for the treatment of ‘cold’ glioblastoma tumors in pts
Tyler Jacks talk was outstanding, Needs be delivered A@TED TALKs, needs become contents in the curriculum of Cell Biology graduate seminar as an Online class. BRAVO @pharma_BI@AVIVA1950
Aviva Lev-Ari added,
Anne E Deconinck@AEDeconinck
My boss, @kochinstitute director Tyler Jacks, presenting beautiful, unpublished work at our 3rd #iesymposium.
#IESYMPOSIUM@pharma_BI@AVIVA1950 Stephanie Dougan (Dana-Farber Cancer Institute) Dept. Virology IAPi outperforms checkpoint blockade in T cell cold tumors reduction of tumor burden gencitabine cross-presenting DCs and CD8 T cells – T cell low 6694c2
#IESYMPOSIUM@pharma_BI@AVIVA1950 Melody Swartz (University of Chicago) Lymphangiogenesis attractive to Native T cells, in VEGF-C tumors T cell homing inhibitors vs block T cell egress inhibitors – Immunotherapy induces T cell killing
#IESYMPOSIUM@pharma_BI@AVIVA1950 Cathy Wu @MGH breakthrough for Brain Tumor #vaccine based neoantigen-specific T cell at intracranial site Single cells brain tissue vs single cells from neoantigen specific T cells – intratumoral neoantigen-specific T cells: mutARGAP35-spacific
#IESYMPOSIUM@pharma_BI@AVIVA1950 Cathy Wu (Massachusetts General Hospital) – CoFounder of NEON Enduring complete radiographic responses after #Neovax + alpha-PD-1 treatment (anti-PD-1) NeoVax vs IVAC Mutanome for melanoma and Glioblastoma clinical trials
#IESYMPOSIUM@pharma_BI@AVIVA1950@TylerJacks@MIT Interrogating markers of T cell dysfunction – chance biology of cells by CRISPR – EGR2 at 2 weeks dysfuntioning is reduced presence of EDR2 mutant class plays role in cell metabolism cell becomes functional regulator CD8 T cell
MISSION The mission of the Koch Institute (KI) is to apply the tools of science and technology to improve the way cancer is detected, monitored, treated and prevented.
APPROACH We bring together scientists and engineers – in collaboration with clinicians and industry partners – to solve the most intractable problems in cancer. Leveraging MIT’s strengths in technology, the life sciences and interdisciplinary research, the KI is pursuing scientific excellence while also directly promoting innovative ways to diagnose, monitor, and treat cancer through advanced technology.
HISTORY The Koch Institute facility was made possible through a $100 million gift from MIT alumnus David H. Koch. Our new building opened in March 2011, coinciding with MIT’s 150th anniversary. Our community has grown out of the MIT Center for Cancer Research (CCR), which was founded in 1974 by Nobel Laureate and MIT Professor Salvador Luria, and is one of seven National Cancer Institute-designated basic (non-clinical) research centers in the U.S.
Biological, chemical, and materials engineers are engaged at the forefront of immunology research. At their disposal is an analytical toolkit honed to solve problems in the petrochemical and materials industries, which share the presence of complex reaction networks, and convective and diffusive molecular transport. Powerful synthetic capabilities have also been crafted: binding proteins can be engineered with effectively arbitrary specificity and affinity, and multifunctional nanoparticles and gels have been designed to interact in highly specific fashions with cells and tissues. Fearless pursuit of knowledge and solutions across disciplinary boundaries characterizes this nascent discipline of immune engineering, synergizing with immunologists and clinicians to put immunotherapy into practice.
The 2019 symposium will include two poster sessions and four abstract-selected talks. Abstracts should be uploaded on the registration page. Abstract submission deadline is November 15, 2018. Registration closes December 14.
Featuring on Day 2, 1/29, 2019:
Session IV
Moderator: Michael Birnbaum, Koch Institute, MIT
Jamie Spangler (John Hopkins University)
“Reprogramming anti-cancer immunity through molecular engineering”
Reprogramming anti-cancer immunity response through molecular engineering”
Cytokines induce receptor dimerization
Clinical Use of cytokines: Pleiotropy, expression and stability isssues
poor pharmacological properties
cytokine therapy: New de novo protein using computational methods
IL-2 signals through a dimeric nad a trimeric receptor complex
IL-2 pleiotropy hinders its therapeutic efficacy
IL-2 activate immunosuppression
potentiation of cytokine activity by anti-IL-2 antibody selectivity
Cytokine binding – Antibodies compete with IL-2 receptor subunits
IL-2Ralpha, IL-2 Rbeta: S4B6 mimickry of alpha allosterically enhances beta
Affinity – molecular eng De Novo design of a hyper-stable, effector biased IL-2
De novo IL-2 poteniator in therapeutic superior to the natural cytokine by molecular engineering
Bryan Bryson (MIT, Department of Biological Engineering)
“Exploiting the macrophage axis in Mycobacterium tuberculosis (Mtb) infection”
TB – who develop Active and why?
Immunological life cycle of Mtb
Global disease Mtb infection outcome varies within individual host
lesion are found by single bacteria
What are the cellular players in immune success
MACROPHAGES – molecular signals enhancing Mtb control of macrophages
modeling the host- macrophages are plastic and polarize
Building “libraries” – surface marker analysis of Microphages
Polarized macrophages are functionally different
quant and qual differences
History of GM-CSF suppresses IL-10
Loss of polarization potential: scRNAseq reveals transcriptional differences Thioredoxin facilitates immune response to Mtb is a marker of an inflammatory macrophage state
functional spectrum of human microphages
Facundo Batista (Ragon Institute (HIV Research) @MGH, MIT and Harvard)
“Vaccine evaluation in rapidly produced custom humanized mouse models”
Effective B cell activation requires 2 signals Antigen and binding to T cell
VDJ UCA (Unmutated common Ancestor)
B Cell Receptor (BCR) co-receptors and cytoskeleton
44% in Women age 24-44
Prototype HIV broadly neutralizing Antibodies (bnAb) do not bind to Env protein – Immunogen design and validation
Human Ig Knock-ins [Light variable 5′ chain length vs 7′ length] decisive to inform immunogenicity – One-Step CRISPR approach does not require ES cell work
Proof of principle with BG18 Germline Heavy Chain (BG18-gH) High-mannose patch – mice exhibit normal B cell development
B cells from naive human germline BG18-gH bind to GT2 immunogen
Interrogate immune response for HIV, Malaria, Zika, Flu
Session V
Moderator: Dane Wittrup, Koch Institute, MIT
Yvonne Chen (University of California, Los Angeles)
“Engineering smarter and stronger T cells for cancer immunotherapy”
Adoptive T-Cell Therapy
Tx for Leukemia – Tumor Antigen escape fro CAR T-cell therapy, CD19/CD20 OR-Gate CARs for prevention of antigen escape – 15 month of development
reduce probability of antigen escape due to two antigen CD19/CD20: Probing limits of modularity in CAR design
In vivo model: 75% wild type & 25% CD19 – relapse occur in the long term, early vs late vs no relapse: Tx with CAR t had no relapse
OR-Gate cause no relapse – Probing limits of modularity in CAR Design
Bispecific CARs are superior to DualCAR: One vs DualCAR (some remained single CAR)
Bispecific CARs exhibit superior antigen-stimulation capacity – OR-Gate CAR Outperforms Single-Input CARs
Lymphoma and Leukemia are 10% of all Cancers
TGF-gamma Rewiring T Cell Response
Activation of t Cell use CAR t
Engineer CAR-T to respond to soluble form of antigens: CD19 CAR Responds to soluble CD19
GFP MCAR responds to Dimeric GFP
“Tumor microenvironment is a scary place”
Michael Birnbaum, MIT, Koch Institute
“A repertoire of protective tumor immunity”
Decoding T and NK cell recognition – understanding immune recognition and signaling function for reprogramming the Immune system – Neoantigen vaccine pipeline
Personal neoantigen vax improve immunotherapy
CLASS I and CLASS II epitomes: MHC prediction performance – more accurate for CLASS I HLA polymorphisms
Immune Epitope DB and Analysis Resources 448,630 Peptide Epitomes
PD-L1 blockade elicits responses in some patients: soft part sarcoma
LAG-3 combined with PD-1 – human peripheral blood tumor
TIM-3 key regulator of T cell and Myeloid cell function: correlates in the TCGA DB with myeloid
Adenosine level in blood or tissue very difficult to measure in blood even more than in tissue – NIR178 + PDR 001 Mono-therapy (NIR178) combine with PD receptor blockage (PDR) – shows benefit
A alone vs A+B in Clinical trial
Session VI
Moderator: Stefani Spranger, Koch Institute, MIT
Tim Springer, Boston Children’s Hospital, HMS
The Milieu Model for TGF-Betta Activation”
Protein Science – Genomics with Protein
Antibody Initiative – new type of antibodies not a monoclonal antibody – a different type
Pro TGF-beta
TGF-beta – not a typical cytokine it is a prodamine for Mature growth factor — 33 genes mono and heterogeneous dimers
Latent TGF-Beta1 crystal structure: prodomaine shields the Growth Factor
Mechanism od activation of pro-TGF-beta – integrin alphaVBeta 6: pro-beta1:2
Simulation in vivo: actin cytoskeleton cytoplasmic domain
blocking antibodies LRRC33 mitigate toxicity on PD-L1 treatment
Alex Shalek, MIT, Department of Chemistry, Koch Institute
“Identifying and rationally modulating cellular drivers of enhanced immunity”
Balance in the Immune system
Profiling Granulomas using Seq-Well 2.0
lung tissue in South Africa of TB patients
Granulomas, linking cell type abundance with burden
Exploring T cells Phenotypes
Cytotoxic & Effector ST@+ Regulatory
Vaccine against TB – 19% effective, only 0 IV BCG vaccination can elicit sterilizing Immunity
Profiling cellular response to vaccination
T cell gene modules across vaccine routes
T Cells, Clusters
Expression of Peak and Memory
Immunotherapy- Identifying Dendritic cells enhanced in HIV-1 Elite Controllers
moving from Observing to Engineering
Cellular signature: NK-kB Signaling
Identifying and testing Cellular Correlates of TB Protection
Beyond Biology: Translation research: Data sets: dosen
Session VII
Moderator: Stefani Spranger, Koch Institute, MIT
Diane Mathis, Harvard Medical School
“Tissue T-regs”
T reg populations in Lymphoid Non–lymphoid Tissues
2009 – Treg tissue homeostasis status – sensitivity to insulin, 5-15% CD4+ T compartment
transcriptome
expanded repertoires TCRs
viceral adipose tissue (VAT) – Insulin
Dependencies: Taget IL-33 its I/1r/1 – encoded Receptor ST2
VAT up-regulate I/1r/1:ST2 Signaling
IL-33 – CD45 negative CD31 negative
mSC Production of IL-33 is Important to Treg
The mesenchyme develops into the tissues of the lymphatic and circulatory systems, as well as the musculoskeletal system. This latter system is characterized as connective tissues throughout the body, such as bone, muscle and cartilage. A malignant cancer of mesenchymal cells is a type of sarcoma.
Age-dependent Treg and mSC changes – Linear with increase in age
Sex-dependent Treg and mSC changes – Female
Treg loss in cases of Obesity leading to fibrosis
Treg keep IL-33-Producing mSCs under rein
Lean tissue vs Obese tissue
Aged mice show poor skeletal muscle repair – it is reverses by IL-33 Injection
Immuno-response: target tissues systemic T reg
Treg and mSC
Aviv Regev, Broad Institute; Koch Institute
“Cell atlases as roadmaps to understand Cancer”
Colon disease UC – genetic underlining risk, – A single cell atlas of healthy and UC colonic mucosa inflammed and non-inflammed: Epithelial, stromal, Immune – fibroblast not observed in UC colon IAFs; IL13RA2 + IL11
Anti TNF responders – epithelial cells
Anti TNF non-responders – inflammatory monocytes fibroblasts
RESISTANCE to anti-cancer therapy: OSM (Inflammatory monocytes-OSMR (IAF)
cell-cell interactions from variations across individuals
Most UC-risk genes are cell type specific
Variation within a cell type helps predict GWAS gene functions – epithelial cell signature – organize US GWAS into cell type specific – genes in associated regions: UC and IBD
Melanoma
malignant cells with resistance in cold niches in situ
cells express the resistance program pre-treatment: resistance UP – cold
Predict checkpoint immunotherapy outcomes
CDK4/6 – computational search predict as program regulators: abemaciclib in cell lines
Poster Presenters
Preeti Sharma, University of Illinois
T cell receptor and CAR-T engineering – T cell therapy
TCR Complex: Vbeta Cbeta P2A Valpha Calpha
CAR-T Aga2 HA scTCR/scFv c-myc
Directed elovution to isolate optimal TCR or CAR
Eng TCR and CARt cell therapy
Use of TCRs against pep/MHC allows targeting a n array of cancer antigens
TCRs are isolated from T cell clones
Conventional TCR identification method vs In Vitro TCR Eng directed evolution
T1 and RD1 TCRs drive activity against MART-1 in CD4+ T cells
CD8+
TCR engineering for Targeting glycosylated cancer antigens
Normal glycosylation vs Aberrant glycosylation
Engineering 237-CARs libraries with conjugated (Tn-OTS8) against multiple human Tn-antigend
In vitro engineering: broaden specificity to multiple peptide backbone
CAR engineering collaborations with U Chicago, U Wash, UPenn, Copenhagen, Germany
Martin LaFleur, HMS
CRISPR- Cas9 Bone marrow stem cells for Cancer Immunotherapy
CHIME: CHimeric IMmune Editing system
sgRNA-Vex
CHIME can be used to KO genes in multiple immune lineages
identify T cell intrinsic effects in the LCMV model Spleen-depleted, Spleen enhanced
Loss of Ptpn2 enhances CD8+ T cell responses to LCMV and Tumors
Ptpn2 deletion in the immune system enhanced tumor immunity
The Immune System, Stress Signaling, Infectious Diseases and Therapeutic Implications: VOLUME 2: Infectious Diseases and Therapeutics and VOLUME 3: The Immune System and Therapeutics (Series D: BioMedicine & Immunology) Kindle Edition – on Amazon.com since September 4, 2017
8:30 – 9:45 Session V Moderator: Stefani Spranger | MIT, Koch Institute
K. Christopher Garcia – Stanford University Exploiting T Cell and Cytokine Receptor Structure and Mechanism to Develop New Immunotherapeutic Strategies
T Cell Receptor, peptide-MHC, 10 to the power of 10 is combinatorics – Library for selection to determine enrichment possibilities
Ligand identification for orphan TCRs
Industrializing process
use pMHC
IL-2 – Receptor Signaling Complex
Effector cells (NK, T)
Engineered T Cell – Tunable expansion, ligand-Receptor interface
Randomize IL-2RBeta interface: Orthogonal receptor vs wild type
In Vivo adoptive transfer model: to quantify orthogonality ratio
CD4, CD8, Treg,C57BL/6J
Ligand discovery
Orthogonal IL-2
Stefani Spranger – MIT, Koch Institute Batf3-DC as Mediators of the T Cell-Inflamed Tumor Microenvironment
Melanoma – solid cancer and other types, Immune inhibitory regulatory pathway patient with Immune response present
T cell-inflamed Tumor vs Non-T cell-inflamed Tumor
identify oncogenic pathways differentially activated between T cell-inflamed and non-Tcell-inflamed infiltration
If on Tumor:
Braf/PTEN
Braf/CAT
Braf/PTEN/CAT
The role of T cell priming – lack of initial
Beta-catenin-expressing tumors fail to prime 2C TCR-transgenic T cells
Deficiency in number of CD8+ and CD103+ dendritic cells
CD103+ DC are essential for T cell Priming and T cell-inflammation #StefaniSpranger
Adoptive transfer of effector 2C T cells fails to control Beta-catenin+ tumors
Vaccination induced anti-gen specific T cell memory fails to control Beta-catenin+ tumors
What cell type in tumor microenvironment effect monilization of T cell
CD103+ Dendritic cellsare source chymokine
Recruitment of effector T cells: Reconstitution od Beta-catenin-expressing SIY+
Are Batf3-DC within the tumor required for the recruitment of effector T cells?
Tumor-residing Batf3-drive CD103+ DC are required for the recruitment of effector T cells
Gene spore for correlation with recturment of effector cells
T cell Priming – CD103+ DC are essential for effector T cells
George Georgiou – University of Texas at Austin The Human Circulating Antibody Repertoire in Infection, Vaccination or Cancer
Serological Antibody Repertoire: in blood or in secretions
Antibody in serum – is difficult sequence identity
Serum IgG – 7-17 mg/ml if less immune deficient if more hyper globular
antibodies produced in long lived plasma cells in the bone marrow — experimentally inaccessible
Discovery of antibodies from the serological repertoire – not B cells
BM-PCs
Serum antibodies function via Fc effector mechanism – complement activation
Ig-SEQ – BCR-SEQ
Repertoire-wide computational modelling of antibody structures
En masse analysis & Mining of the Human Native Antibody Repertoire
hypervariable – High-Throughput Single B Cell VH:VL (or TCRalpha, beta) sequencing
HuNoV causes 800 death in the US per year of immune deficient
Influenza Trivalent Vaccine: Antibodies to hemaggiutinin: H1, H3, and B COmponenet
Abundant H1 +H3 Serum IgGs do not neutralize but confer Protection toInfluenza challenge with Live Virus #GeorgeGeorgiou
Non-Neutralizing Antibodies: The role of Complement in Protection
9:45 – 10:15 Break
10:15 – 11:30 Session VI Moderator: K. Dane Wittrup | MIT, Koch Institute
Harvey Lodish – Whitehead Institute and Koch Institute Engineered Erythrocytes Covalently Linked to Antigenic Peptides Can Protect Against Autoimmune Disease
Modified Red blood cells are microparticles for introducing therapeutics & diagnostics into the human body
Bool transfusion is widely used therapeutics
Covalently linking unique functional modalities to mouse or human red cells produced in cell culture:
PRODUCTION OF HUMAN RED BLOD CELLS EXPRESSING A FOREIN PROTEIN: CD34+ stem/progenitor cells that generates normal enucleated RBC.
PPAR-alpha and glucocorticoticoid receptor
Norman morphology: Sortase A is a bactrial transpeptidase that covalently links a “donor”
Engineering Normal Human RBC biotin-LPETG
Covelantely – Glycophorin A with camelid VHHs specific for Botulinum toxin A or B
HLA-DR4 library design and selection to enrich HLA-DM: Amino Acid vs Peptide position: Depleted vs Enriched – relative to expected for NNK codon
6852 _ predicted to bind vs 220 Non-binding peptides
HLA polymorphism: repertoire differences caused by
Antigen – T cell-driven antigen discovery: engaging Innate and Adaptive Immune response
Sorting TIL and select: FOcus of T cell-driven antigen discovery
T cell-driven antigen discovery: TCR
Jennifer R. Cochran – Stanford University Innate and Adaptive Integrin-targeted Combination Immunotherapy
alpa-TAA
TargetingIntegrin = universal targetinvolved in binding to several receptors: brest, lung, pancreatic, brain tumors arising by mutations – used as a handle for binding to agents
NOD201 Peptide-Fc Fusion: A Psudo Ab
Handle the therapeutics: NOD201 + alphaPD1
NOD201 effectively combines with alphaPD-L1, alphaCTLA-4, and alpha4-1BB/CD137
Corresponding monotherapies vs ComboTherapy invoking Innate and Adaptive Immune System
Microphages, CD8+ are critical vs CD4+ Neutrophils, NK cells, B cells #JenniferR. Cochran
Macrophages activation is critical – Day 4, 4 and 5
NOD201 + alphaPD1 combo increases M1 macrophages
Who are the best responders to PD1 – genes that are differentially expressed
NOD201 deives T cells reaponses through a “vaccinal” effect
CAncer Immune CYcle
Integrin – localization
Prelim NOD201 toxicity studies: no significant effects
Targeting multiple integrins vs antibodies RJ9 – minimal effect
NOD201 – manufacturability – NEW AGENT in Preclinical stage
2:15 – 2:45 Break
2:45 – 3:35 Session VIII Moderator: Jianzhu Chen | MIT, Koch Institute
Jennifer Wargo – MD Anderson Cancer Center Understanding Responses to Cancer Therapy: The Tissue is the Issue, but the Scoop is in the Poop
Optimize Targeted Treatment response
Translational research in patients on targeted therapy revealed molecular and immune mechanisms of response and resistance
Molecular mechanisms – T cell infiltrate after one week of therapy
Role of tumor stroma in mediating resistance to targeted therapy
Tumor microenvironment
Intra-tumoral bacteria identified in patients with Pancreatic Cancer
Translational research in patients on immune checkpoint blockade revealed molecualr and immune mechanism of response and resistance
Biomarkers not found
SYstemic Immunity and environment (temperature) on response to checkpoint blockade – what is the role?
Role of mIcrobiome in shaping response to checkpoint blockade in Melanoma
Microbime and GI Cancer
Diversity of the gut microbiome is associated with differential outcomes in the setting of stem cell transplant in AML
Oral and gut fecal microbiome in large cohort patient with metastatic melanoma undergoing systemic therapy
Repeat oral & gut AFTER chemo
WGSeq – Diversity of microbiome and response (responders vs non-responders to anti PD-1 – High diversity of microbiome have prolonged survival to PD-1 blockade
Anti tumor Immunity and composition of gut microbiome in patient on anti-PD-1 favorable AND higher survival #JenniferWargo
Enhance therapeutic responses in lang and renal carcinoma: If on antibiotic – poorer survival
sharing data important across institutions
Jianzhu Chen – MIT, Koch Institute Modulating Macrophages in Cancer Immunotherapy
Humanized mouth vs de novo human cancer
B cell hyperplasia
double hit lymphoma
AML
Overexpression of Bcl-2 & Myc in B cells leads to double-hit lymphoma
antiCD52 – CLL
Spleen, Bone marrow, Brain
Microphages are required to kill Ab-bound lymphoma cells in vivo #JianzhuChen
COmbinatorial chemo-Immunotherapy works for solid tumors: treating breast cancer in humanized mice
Infiltration of monocytic cells in the bone marrow
Cyclophosphophamide-antibody synergy extending to solid tumor and different antibodies #JianzhuChen
Polarization of macrophages it is dosage-dependent M1 and M2
Antibiotic induces expression of M1 polarizing supresses development and function of tumor-associated macrophages (TAM)
Antibiotic inhibits melanoma growth by activating macrophages in vivo #JianzhuChen
Outsource a part of the T cell’s immune value chain, propose cancer immunotherapy researchers, from patient T cells to donor T cells. The novel allogeneic approach could rely on T-cell receptor gene transfer to generate broad and tumor-specific T-cell immune responses. [NIAID]
A new cancer immunotherapy approach could essentially outsource a crucial T-cell function. This function, T-cell reactivity to specific cancer antigens, is sometimes lacking in cancer patients. Yet, according to a new proof-of-principle study, these patients could benefit from T cells provided by healthy donors. Specifically, the healthy donors’ T cells could be used to broaden the T-cell receptor repertoires of the cancer patients’ T cells.
Ultimately, this approach relies on a cancer immunotherapy technique called T-cell receptor (TCR) transfer, or the genetic transfer of TCR chains. TCR transfer can be used to outsource the T cell’s learning function, the process by which a T cell acquires the ability to recognize foreign antigens—in this case, the sort of proteins that can be expressed on the surface of cancer cells. Because cancer cells harbor faulty proteins, they can also display foreign protein fragments, also known as neoantigens, on their surface, much in the way virus-infected cells express fragments of viral proteins.
The approach was detailed in a paper that appeared May 19 in the journal Science, in an article entitled, “Targeting of Cancer Neoantigens with Donor-Derived T Cell Receptor Repertoires.” This article, by scientists based at the Netherlands Cancer Institute and the University of Oslo, describes a novel strategy to broaden neoantigen-specific T-cell responses. Such a strategy would be useful in overcoming a common limitation seen in the immune response to cancer: Neoantigen-specific T-cell reactivity is generally limited to just a few mutant epitopes, even though the number of predicted epitopes is large.
“We demonstrate that T cell repertoires from healthy donors provide a rich source of T cells that specifically recognize neoantigens present on human tumors,” the study’s authors wrote. “Responses to 11 epitopes were observed, and for the majority of evaluated epitopes, potent and specific recognition of tumor cells endogenously presenting the neoantigens was detected.”
First, the researchers mapped all possible neoantigens on the surface of melanoma cells from three different patients. In all three patients, the cancer cells seemed to display a large number of different neoantigens. But when the researchers tried to match these to the T cells derived from within the patient’s tumors, most of these aberrant protein fragments on the tumor cells went unnoticed.
Next, the researchers tested whether the same neoantigens could be seen by T cells derived from healthy volunteers. Strikingly, these donor-derived T cells could detect a significant number of neoantigens that had not been seen by the patients’ T cells.
“Many of the T cell reactivities [among donor T cells] involved epitopes that in vivo were neglected by patient autologous tumor-infiltrating lymphocytes,” the authors of the Science article continued. “T cells re-directed with T cell receptors identified from donor-derived T cells efficiently recognized patient-derived melanoma cells harboring the relevant mutations, providing a rationale for the use of such ‘outsourced’ immune responses in cancer immunotherapy.”
“In a way, our findings show that the immune response in cancer patients can be strengthened; there is more on the cancer cells that makes them foreign that we can exploit. One way we consider doing this is finding the right donor T cells to match these neoantigens,” said Ton Schumacher, Ph.D., a principal investigator at the Netherlands Cancer Institute. “The receptor that is used by these donor T cells can then be used to genetically modify the patient’s own T cells so these will be able to detect the cancer cells.”
“Our study shows that the principle of outsourcing cancer immunity to a donor is sound,” added Johanna Olweus, M.D., Ph.D., who heads a research group at the University of Oslo. “However, more work needs to be done before patients can benefit from this discovery. Thus, we need to find ways to enhance the throughput.”
“We are currently exploring high-throughput methods to identify the neoantigens that the T cells can ‘see’ on the cancer and isolate the responding cells. But the results showing that we can obtain cancer-specific immunity from the blood of healthy individuals are already very promising.”
Targeting of cancer neoantigens with donor-derived T cell receptor repertoires
Accumulating evidence suggests that clinically efficacious cancer immunotherapies are driven by T cell reactivity against DNA mutation-derived neoantigens. However, among the large number of predicted neoantigens, only a minority is recognized by autologous patient T cells, and strategies to broaden neoantigen specific T cell responses are therefore attractive. Here, we demonstrate that naïve T cell repertoires of healthy blood donors provide a source of neoantigen-specific T cells, responding to 11/57 predicted HLA-A2-binding epitopes from three patients. Many of the T cell reactivities involved epitopes that in vivo were neglected by patient autologous tumor-infiltrating lymphocytes. Finally, T cells re-directed with T cell receptors identified from donor-derived T cells efficiently recognized patient-derived melanoma cells harboring the relevant mutations, providing a rationale for the use of such “outsourced” immune responses in cancer immunotherapy.
Metabolic maintenance of cell asymmetry following division in activated T lymphocytes.
Asymmetric cell division, the partitioning of cellular components in response to polarizing cues during mitosis, has roles in differentiation and development. It is important for the self-renewal of fertilized zygotes in Caenorhabditis elegans and neuroblasts in Drosophila, and in the development of mammalian nervous and digestive systems. T lymphocytes, upon activation by antigen-presenting cells (APCs), can undergo asymmetric cell division, wherein the daughter cell proximal to the APC is more likely to differentiate into an effector-like T cell and the distal daughter is more likely to differentiate into a memory-like T cell. Upon activation and before cell division, expression of the transcription factor c-Myc drives metabolic reprogramming, necessary for the subsequent proliferative burst. Here we find that during the first division of an activated T cell in mice, c-Myc can sort asymmetrically. Asymmetric distribution of amino acid transporters, amino acid content, and activity of mammalian target of rapamycin complex 1 (mTORC1) is correlated with c-Myc expression, and both amino acids and mTORC1 activity sustain the differences in c-Myc expression in one daughter cell compared to the other. Asymmetric c-Myc levels in daughter T cells affect proliferation, metabolism, and differentiation, and these effects are altered by experimental manipulation of mTORC1 activity or c-Myc expression. Therefore, metabolic signalling pathways cooperate with transcription programs to maintain differential cell fates following asymmetric T-cell division.
T cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy associated with Notch pathway mutations. While both normal activated and leukemic T cells can utilize aerobic glycolysis to support proliferation, it is unclear to what extent these cell populations are metabolically similar and if differences reveal T-ALL vulnerabilities. Here we show that aerobic glycolysis is surprisingly less active in T-ALL cells than proliferating normal T cells and that T-ALL cells are metabolically distinct. Oncogenic Notch promoted glycolysis but also induced metabolic stress that activated 5′ AMP-activated kinase (AMPK). Unlike stimulated T cells, AMPK actively restrained aerobic glycolysis in T-ALL cells through inhibition of mTORC1 while promoting oxidative metabolism and mitochondrial Complex I activity. Importantly, AMPK deficiency or inhibition of Complex I led to T-ALL cell death and reduced disease burden. Thus, AMPK simultaneously inhibits anabolic growth signaling and is essential to promote mitochondrial pathways that mitigate metabolic stress and apoptosis in T-ALL.
Obesity and diabetes are associated with excessive inflammation and impaired wound healing. Increasing evidence suggests that macrophage dysfunction is responsible for these inflammatory defects. In the setting of excess nutrients, particularly dietary saturated fatty acids (SFAs), activated macrophages develop lysosome dysfunction, which triggers activation of the NLRP3 inflammasome and cell death. The molecular pathways that connect lipid stress to lysosome pathology are not well understood, but may represent a viable target for therapy. Glutamine uptake is increased in activated macrophages leading us to hypothesize that in the context of excess lipids glutamine metabolism could overwhelm the mitochondria and promote the accumulation of toxic metabolites. To investigate this question we assessed macrophage lipotoxicity in the absence of glutamine using LPS-activated peritoneal macrophages exposed to the SFA palmitate. We found that glutamine deficiency reduced lipid induced lysosome dysfunction, inflammasome activation, and cell death. Under glutamine deficient conditions mTOR activation was decreased and autophagy was enhanced; however, autophagy was dispensable for the rescue phenotype. Rather, glutamine deficiency prevented the suppressive effect of the SFA palmitate on mitochondrial respiration and this phenotype was associated with protection from macrophage cell death. Together, these findings reveal that crosstalk between activation-induced metabolic reprogramming and the nutrient microenvironment can dramatically alter macrophage responses to inflammatory stimuli.
Immunoregulatory Protein B7-H3 Reprograms Glucose Metabolism in Cancer Cells by ROS-Mediated Stabilization of HIF1α
CD8(+) T cells can respond to unrelated infections in an Ag-independent manner. This rapid innate-like immune response allows Ag-experienced T cells to alert other immune cell types to pathogenic intruders. In this study, we show that murine CD8(+) T cells can sense TLR2 and TLR7 ligands, resulting in rapid production of IFN-γ but not of TNF-α and IL-2. Importantly, Ag-experienced T cells activated by TLR ligands produce sufficient IFN-γ to augment the activation of macrophages. In contrast to Ag-specific reactivation, TLR-dependent production of IFN-γ by CD8(+) T cells relies exclusively on newly synthesized transcripts without inducing mRNA stability. Furthermore, transcription of IFN-γ upon TLR triggering depends on the activation of PI3K and serine-threonine kinase Akt, and protein synthesis relies on the activation of the mechanistic target of rapamycin. We next investigated which energy source drives the TLR-induced production of IFN-γ. Although Ag-specific cytokine production requires a glycolytic switch for optimal cytokine release, glucose availability does not alter the rate of IFN-γ production upon TLR-mediated activation. Rather, mitochondrial respiration provides sufficient energy for TLR-induced IFN-γ production. To our knowledge, this is the first report describing that TLR-mediated bystander activation elicits a helper phenotype of CD8(+) T cells. It induces a short boost of IFN-γ production that leads to a significant but limited activation of Ag-experienced CD8(+) T cells. This activation suffices to prime macrophages but keeps T cell responses limited to unrelated infections.
The bidirectional interaction between the immune system and whole-body metabolism has been well recognized for many years. Via effects on adipocytes and hepatocytes, immune cells can modulate whole-body metabolism (in metabolic syndromes such as type 2 diabetes and obesity) and, reciprocally, host nutrition and commensal-microbiota-derived metabolites modulate immunological homeostasis. Studies demonstrating the metabolic similarities of proliferating immune cells and cancer cells have helped give birth to the new field of immunometabolism, which focuses on how the cell-intrinsic metabolic properties of lymphocytes and macrophages can themselves dictate the fate and function of the cells and eventually shape an immune response. We focus on this aspect here, particularly as it relates to regulatory T cells.
Figure 1: Proposed model for the metabolic signatures of various Treg cell subsets.
(a) Activated CD4+ T cells that differentiate into the Teff cell lineage (green) (TH1 or TH17 cells) are dependent mainly on carbon substrates such as glucose and glutamine for their anabolic metabolism. In contrast to that, pTreg cells…
T-bet is a key modulator of IL-23-driven pathogenic CD4+ T cell responses in the intestine
IL-23 is a key driver of pathogenic Th17 cell responses. It has been suggested that the transcription factor T-bet is required to facilitate IL-23-driven pathogenic effector functions; however, the precise role of T-bet in intestinal T cell responses remains elusive. Here, we show that T-bet expression by T cells is not required for the induction of colitis or the differentiation of pathogenic Th17 cells but modifies qualitative features of the IL-23-driven colitogenic response by negatively regulating IL-23R expression. Consequently, absence of T-bet leads to unrestrained Th17 cell differentiation and activation characterized by high amounts of IL-17A and IL-22. The combined increase in IL-17A/IL-22 results in enhanced epithelial cell activation and inhibition of either IL-17A or IL-22 leads to disease amelioration. Our study identifies T-bet as a key modulator of IL-23-driven colitogenic responses in the intestine and has important implications for understanding of heterogeneity among inflammatory bowel disease patients.
Th17 cells are enriched at mucosal sites, produce high amounts of IL-17A, IL-17F and IL-22, and have an essential role in mediating host protective immunity against a variety of extracellular pathogens1. However, on the dark side, Th17 cells have also been implicated in a variety of autoimmune and chronic inflammatory conditions, including inflammatory bowel disease (IBD)2. Despite intense interest, the cellular and molecular cues that drive Th17 cells into a pathogenic state in distinct tissue settings remain poorly defined.
The Th17 cell programme is driven by the transcription factor retinoid-related orphan receptor gamma-t (RORγt) (ref. 3), which is also required for the induction and maintenance of the receptor for IL-23 (refs 4, 5). The pro-inflammatory cytokine IL-23, composed of IL-23p19 and IL-12p40 (ref. 6), has been shown to be a key driver of pathology in various murine models of autoimmune and chronic inflammatory disease such as experimental autoimmune encephalomyelitis (EAE)7, collagen induced arthritis8 and intestinal inflammation9, 10, 11, 12. Several lines of evidence, predominantly derived from EAE, suggest that IL-23 promotes the transition of Th17 cells to pathogenic effector cells9, 10, 11, 12. Elegant fate mapping experiments of IL-17A-producing cells during EAE have shown that the majority of IL-17A+IFN-γ+ and IL-17A−IFN-γ+ effector cells arise from Th17 cell progeny13. This transition of Th17 cells into IFN-γ-producing ‘ex’ Th17 cells required IL-23 and correlated with increased expression of T-bet. The T-box transcription factor T-bet drives the Th1 cell differentiation programme14 and directly transactivates the Ifng gene by binding to its promoter as well as multiple enhancer elements15. Indeed, epigenetic analyses have revealed that the loci for T-bet and IFN-γ are associated with permissive histone modifications in Th17 cells suggesting that Th17 cells are poised to express T-bet which could subsequently drive IFN-γ production16, 17.
A similar picture is emerging in the intestine where IL-23 drives T-cell-mediated intestinal pathology which is thought to be dependent on expression of T-bet18 and RORγt (ref. 19) by T cells. In support of this we have recently shown that IL-23 signalling in T cells drives the emergence of IFN-γ producing Th17 cells in the intestine during chronic inflammation20. Collectively these studies suggest a model whereby RORγt drives differentiation of Th17 cells expressing high amounts of IL-23R, and subsequently, induction of T-bet downstream of IL-23 signalling generates IL-17A+IFN-γ+ T cells that are highly pathogenic. Indeed, acquisition of IFN-γ production by Th17 cells has been linked to their pathogenicity in several models of chronic disease13, 21, 22, 23, 24 and a population of T cells capable of producing both IL-17A and IFN-γ has also been described in intestinal biopsies of IBD patients25, 26.
However, in the context of intestinal inflammation, it remains poorly defined whether the requirement for RORγt and T-bet reflects a contribution of Th17 and Th1 cells to disease progression or whether Th17 cells require T-bet co-expression to exert their pathogenic effector functions. Here, we use two distinct models of chronic intestinal inflammation and make the unexpected finding that T-bet is dispensable for IL-23-driven colitis. Rather the presence of T-bet serves to modify the colitogenic response restraining IL-17 and IL-22 driven pathology. These data identify T-bet as a key modulator of IL–23-driven colitogenic effector responses in the intestine and have important implications for understanding of heterogeneous immune pathogenic mechanisms in IBD patients.
Figure 1: IL-23 signalling is required for bacteria-driven T-cell-dependent colitis and the emergence of IL-17A+IFN-γ+ T cells.
C57BL/6 WT and Il23r−/− mice were infected orally with Hh and received weekly i.p. injections of IL-10R blocking antibody. Mice were killed at 4 weeks post infection and assessed for intestinal inflammation. (a) Colitis scores. (b) Typhlitis sores. (c) Representative photomicrographs of colon and caecum (× 10 magnification; scale bars, 200μM). (d) Representative flow cytometry plots of colonic lamina propria gated on viable CD4+ T cells. (e) Frequencies of IL-17A+ and/or IFN-γ+ CD4+ T cells present in the colon. Data represent pooled results from two independent experiments (n=12 for WT, n=10 for Il23r−/−). Bars are the mean and each symbol represents an individual mouse. *P<0.05, ***P<0.001 as calculated by Mann–Whitney U test.
C57BL/6 Rag1−/− mice were injected i.p. with 4 × 105 CD4+CD25−CD45RBhi T cells from C57BL/6 WT,Rorc−/− or Tbx21−/− donors. Mice were killed when recipients of Tbx21−/− T cells developed clinical signs of disease (4–6 weeks) and assessed for intestinal inflammation. (a) Colitis scores. (b) Representative photomicrographs of proximal colon sections (× 10 magnification; scale bars, 200μM). (c) Concentration of cytokines released from colon explants into the medium after overnight culture. Data represent pooled results from two independent experiments (n=14 for WT, n=11 for Rorc−/−, n=14 forTbx21−/−). Bars are the mean and each symbol represents an individual mouse. Bars are the mean and error bars represent s.e.m. *P<0.05, **P<0.01, ***P<0.001 as calculated by Kruskal–Wallis one-way ANOVA with Dunn’s post-test.
C57BL/6 Rag1−/− mice were injected i.p. with 4×105 CD4+CD25−CD45RBhi T cells from C57BL/6 WT,Rorc−/− or Tbx21−/− donors. Mice were killed when recipients of Tbx21−/−T cells developed clinical signs of disease (4–6 weeks). (a) Representative plots of IL-17A and IFN-γ expression in colonic CD4+ T cells. (b) Frequencies of IL-17A+ and/or IFN-γ+ cells among colonic CD4+ T cells. (c) Total numbers of IL-17A+and/or IFN-γ+ CD4+ T cells present in the colon. Data represent pooled results from three independent experiments (n=20 for WT, n=18 for Tbx21−/−, n=12 for Rorc−/−). Bars are the mean and each symbol represents an individual mouse. *P<0.05, **P<0.01, ***P<0.001 as calculated by Kruskal–Wallis one-way ANOVA with Dunn’s post-test.
T-bet deficiency promotes an exacerbated Th17-type response
Our transfer of Tbx21−/− T cells revealed a striking increase in the frequency of IL-17A+IFN-γ−cells (Fig. 3) and we reasoned that T-bet-deficiency could impact on Th17 cell cytokine production. Therefore, we transferred WT or Tbx21−/− CD4+ T cells into Rag1−/− recipients and measured the expression of RORγt, IL-17A, IL-17F and IL-22 by CD4+ T cells isolated from the colon. In agreement with our earlier findings, Tbx21−/− T cells gave rise to significantly increased frequencies of RORγt-expressing T cells capable of producing IL-17A (Fig. 4a). Furthermore, T-bet deficiency also led to a dramatic expansion of IL-17F and IL-22-expressing cells, which constituted only a minor fraction in WT T cells (Fig. 4a,b). By contrast, the frequency of granulocyte-macrophage colony-stimulating factor (GM-CSF) and IFN-γ producing cells was significantly reduced in T-bet-deficient T cells as compared with WT T cells. When analysed in more detail we noted that the production of IL-17A, IL-17F and IL-22 increased specifically in T-bet-deficient IL-17A+IFN-γ+ T cells as compared with WT T cells whereas IFN-γ production decreased overall in the absence of T-bet as expected (Supplementary Fig. 4A). Similarly, GM-CSF production was also generally reduced in Tbx21−/− CD4+ T cells further suggesting a shift in the qualitative nature of the T cell response.
Figure 4: T-bet-deficient CD4+ T cells promote an exacerbated Th17-type inflammatory response.
C57BL/6 Rag1−/− mice were injected i.p. with 4×105 CD4+CD25−CD45RBhi T cells from C57BL/6 WT orTbx21−/− donors. Mice were killed when recipients of Tbx21−/−T cells developed clinical signs of disease (4–6 weeks). (a) Representative plots of cytokines and transcription factors in WT or Tbx21−/− colonic CD4+ T cells. (b) Frequency of IL-17A+, IL-17F+, IL-22+, GM-CSF+ or IFN-γ+ colonic T cells in WT orTbx21−/−. (c) quantitative reverse transcription PCR (qRT-PCR) analysis of mRNA levels of indicated genes in colon tissue homogenates. (d) Total number of neutrophils (CD11b+ Gr1high) in the colon. (e) Primary epithelial cells were isolated from the colon of steady state C57BL/6 Rag1−/− mice and stimulated with 10ngml−1 cytokines for 4h after which cells were harvested and analysed by qRT-PCR for the indicated genes. Data in b–d represent pooled results from two independent experiments (n=14 for WT, n=11 for Tbx21−/−). Bars are the mean and error bars represent s.e.m. Data in e are pooled results from four independent experiments, bars are the mean and error bars represent s.e.m. *P<0.05, **P<0.01,***P<0.001 as calculated by Mann–Whitney U test.
T-bet-deficient colitis depends on IL-23, IL-17A and IL-22
In the present study we show that bacteria-driven colitis is associated with the IL-23-dependent emergence of IFN-γ-producing Th17 cells co-expressing RORγt and T-bet. Strikingly, while RORγt is required for the differentiation of IFN-γ-producing Th17 cells and induction of colitis, T-bet is dispensable for the emergence of IL-17A+IFN-γ+ T cells and intestinal pathology. Our results show that instead of a mandatory role in the colitogenic response, the presence of T-bet modulates the qualitative nature of the IL-23-driven intestinal inflammatory response. In the presence of T-bet, IL-23-driven colitis is multifunctional in nature and not functionally dependent on either IL-17A or IL-22. By contrast, in the absence of T-bet a highly polarized colitogenic Th17 cell response ensues which is functionally dependent on both IL-17A and IL-22. T-bet-deficient T cells are hyper-responsive to IL-23 resulting in enhanced STAT3 activation and downstream cytokine secretion providing a mechanistic basis for the functional changes. These data newly identify T-bet as a key modulator of IL-23-driven colitogenic CD4+ T cell responses.
Contrary to our expectations T-bet expression by CD4 T cells was not required for their pathogenicity. In keeping with the negative effect of T-bet on Th17 differentiation40, 41, 42, we observed highly polarized Th17 responses in T-bet-deficient intestinal T cells. Early studies demonstrated that IFN-γ could suppress the differentiation of Th17 cells40 and thus the reduced IFN-γ production by Tbx21−/−T cells could facilitate Th17 cell generation. However, our co-transfer studies revealed unrestrained Th17 differentiation of Tbx21−/− T cells even in the presence of WT T cells, suggesting a cell autonomous role for T-bet-mediated suppression of the Th17 programme. Indeed, the role of T-bet as a transcriptional repressor of the Th17 cell fate has been described recently. For example, T-bet physically interacts with and sequesters Runx1, thereby preventing Runx1-mediated induction of RORγt and Th17 cell differentiation43. In addition, T-bet binds directly to and negatively regulates expression of many Th17-related genes15, 34 and we identified IL23r to be repressed in a T-bet-dependent manner. In line with this we show here that T-bet-deficient intestinal T cells express higher amounts of Il23r as well as Rorc. This resulted in enhanced IL-23-mediated STAT3 activation and increased production of IL-17A and IL-22. It has also been suggested that T-bet activation downstream of IL-23R signalling is required for pathogenic IL-23-driven T cell responses43, 44. However, we did not find a role for IL-23 in the induction and/or maintenance of T-bet expression and colitis induced by T-bet-deficient T cells was IL-23 dependent. Collectively, these findings demonstrate that T-bet deficiency leads to unrestrained expansion of colitogenic Th17 cells, which is likely mediated through enhanced activation of the IL-23R-STAT3 pathway.
The observation that T-bet-deficient T cells retain their colitogenic potential is in stark contrast to earlier studies. Neurath et al.18 convincingly showed that adoptive transfer of Tbx21−/− CD4+ T cells into severe combined immunodeficiency (SCID) recipients failed to induce colitis and this correlated with reduced IFN-γ and increased IL-4 production. Another study revealed that IL-4 plays a functional role in inhibiting the colitogenic potential of Tbx21−/− T cells, as recipients ofStat6−/−Tbx21−/− T cells developed severe colitis37. Importantly, the intestinal inflammation that developed in recipients of Stat6−/−Tbx21−/− T cells could be blocked by administration of IL-17A neutralizing antibody, suggesting that the potent inhibitory effect of IL-4/STAT6 signals on Th17 differentiation normally prevent colitis induced by Tbx21−/− T cells37. Various explanations could account for the discrepancy between our study and those earlier findings. First, in contrast to the published reports, we used naïve Tbx21−/− CD4+ T cells from C57BL/6 mice instead of BALB/c mice. An important difference between Tbx21−/− CD4+ T cells from these genetic backgrounds appears to be their differential susceptibility to suppression by IL-4/STAT6 signals. We found that transfer of Tbx21−/− T cells induced IL-17A-dependent colitis despite increased frequencies of IL-4-expressing cells in the intestine. This discrepancy may be due to higher amounts of IL-4 produced by activated CD4+ T cells from BALB/c versus C57BL/6 mice45, leading to the well-described Th2-bias of the BALB/c strain45. Second, differences in the composition of the intestinal microbiota between animal facilities can have a substantial effect on skewing CD4+ T cells responses. In particular, the Clostridium-related segmented filamentous bacteria (SFB) have been shown to drive the emergence of IL-17 and IL-22 producing CD4+ T cells in the intestine46. Importantly, the ability of naïve CD4+ T cells to induce colitis is dependent on the presence of intestinal bacteria, as germ-free mice do not develop pathology upon T cell transfer47. In line with this, we previously described that colonization of germ-free mice with intestinal microbiota containing SFB was necessary to restore the development of colitis47. Since our Rag1−/− colony is SFB+ and the presence of SFB was not reported in the previous studies, it is possible that differences in SFB colonization status contributed to the observed differences in pathogenicity ofTbx21−/− T cells.
It is important to note that T-bet-deficient T cells did not induce more severe colitis than WT T cells but rather promoted a distinct mucosal inflammatory response. Colitis induced by WT T cells is characterized by a multifunctional response with high amounts of IFN-γ and GM-CSF and a lower IL-17A and IL-22 response. Consistent with this, we have shown that blockade of GM-CSF abrogates T cell transfer colitis48 as well as bacteria-driven intestinal inflammation49 in T-bet sufficiency whereas blockade of IL-17A or IL-22 fails to do so. By contrast T-bet deficiency leads to production of high amounts of IL-17A and IL-22 in the colon and neutralization of either was sufficient to reduce intestinal pathology. Our in vitro experiments suggest that IL-17A and IL-22 synergise to promote intestinal epithelial cell responses, which may in part explain the efficacy of blocking IL-17A or IL-22 in colitis induced by T-bet-deficient T cells. A similar synergistic interplay has been described in the lung where IL-22 served a tissue protective function in homeostasis but induced airway inflammation in the presence of IL-17A (ref. 50). This highlights the complexity of the system in health and disease, and the need for a controlled production of both cytokines. We describe here only one mechanism of how IL-17A/IL-22 induce a context-specific epithelial cell response that potentially impacts on the order or composition of immune cell infiltration. Overall, these results provide a new perspective on T-bet, revealing its role in shaping the qualitative nature of the IL-23-driven colitogenic T cell response.
We also describe here the unexpected finding that a substantial proportion of T-bet-deficient intestinal T cells retain the ability to express IFN-γ. To investigate the potential mechanisms responsible for T-bet-independent IFN-γ production by intestinal CD4+ T cells we focused on two transcription factors, Runx3 and Eomes. Runx3 has been shown to promote IFN-γ expression directly through binding to the Ifng promoter38 and Eomes is known to compensate for IFN-γproduction in T-bet-deficient Th1 cells37. We found IL-23-mediated induction of Runx3 protein in WT and Tbx21−/− T cells isolated from the intestine, thus identifying Runx3 downstream of IL-23R signalling. By contrast, we could only detect Eomes protein and its induction by IL-23 in T-bet-deficient but not WT T cells. Thus, Runx3 and Eomes are activated in response to IL-23 in T-bet-deficient cells and are likely to be drivers of T-bet-independent IFN-γ production. In support of this we found that the majority of T-bet-deficient IL-17A−IFN-γ+ T cells expressed Eomes. However, only a minor population of IL-17A+IFN-γ+ T cells stained positive for Eomes, suggesting the existence of alternative pathways for IFN-γ production by Th17 cells. Intriguingly, a recent study identified Runx3 and Runx1 as the transcriptional regulators critical for the differentiation of IFN-γ-producing Th17 cells51. The author’s demonstrated that ectopic expression of Runx transcription factors was sufficient to induce IFN-γ production by Th17 cells even in the absence of T-bet. These findings, combined with our data on Runx3 activation downstream of IL-23R signalling strongly suggest that Runx3 rather than Eomes is driving IFN-γ expression by intestinal Th17 cells.
We have not formally addressed the role of IFN-γ in colitis driven by T-bet-deficient T cells. A recent report by Zimmermann et al.52 found that antibody-mediated blockade of IFN-γ ameliorates colitis induced by WT or T-bet-deficient T cells suggesting IFN-γ also contributes to the colitogneic response mediated by T-bet-deficient T cells as originally described for WT T cells53, 54. By contrast with our results the Zimmerman study found that IL-17A blockade exacerbated colitis following transfer of Tbx21−/− T cells. The reason for the differential role of IL-17A in the two studies is not clear but it is notable that the Zimmerman study was performed in the presence of co-infection with SFB and Hh, and this strong inflammatory drive may alter the pathophysiological role of particular cytokines. Together the data indicate that T-bet deficiency in T cells does not impede their colitogenic activity but that the downstream effector cytokines of the response are context dependent.
In conclusion, our data further underline the essential role for IL-23 in intestinal inflammation and demonstrate that T-bet is an important modulator of the IL–23-driven effector T cell response. The colitogenic T cell response in a T-bet sufficient environment is multifunctional with a dominant GM-CSF and IFN-γ response. By contrast T-bet-deficient colitogenic responses are dominated by IL-17A and IL-22-mediated immune pathology. These results may have significant bearing on human IBD where it is now recognized that differential responsiveness to treatment may reflect considerable disease heterogeneity. As such, identification of suitable biomarkers such as immunological parameters, that allow stratification of patient groups, is becoming increasingly important55. Genome-wide association studies have identified polymorphisms in loci related to innate and adaptive immune arms that confer increased susceptibility to IBD. Among these are Th1 (STAT4, IFNG and STAT1) as well as Th17-related genes (RORC, IL23R and STAT3) (refs56, 57). Thus, detailed profiling of the T cell response in IBD patients may help identify appropriate patient groups that are most likely to benefit from therapeutic blockade of certain effector cytokines. Finally, our studies highlight the importance of IL-23 in the intestinal inflammatory hierarchy and suggest that IL-23 could be an effective therapeutic target across a variety of patient groups.
Yale study: How antibodies access neurons to fight infection
Yale scientists have solved a puzzle of the immune system: how antibodies enter the nervous system to control viral infections. Their finding may have implications for the prevention and treatment of a range of conditions, including herpes and Guillain-Barre syndrome, which has been linked to the Zika virus.
Many viruses — such as West Nile, Zika, and the herpes simplex virus — enter the nervous system, where they were thought to be beyond the reach of antibodies. Yale immunobiologists Akiko Iwasaki and Norifumi Iijima used mice models to investigate how antibodies could gain access to nerve tissue in order to control infection.
In mice infected with herpes, they observed a previously under-recognized role of CD4 T cells, a type of white blood cell that guards against infection by sending signals to activate the immune system. In response to herpes infection, CD4 T cells entered the nerve tissue, secreted signaling proteins, and allowed antibody access to infected sites. Combined, CD4 T cells and antibodies limited viral spread.
“This is a very elegant design of the immune system to allow antibodies to go to the sites of infection,” said Iwasaki. “The CD4 T cells will only go to the site where there is a virus. It’s a targeted delivery system for antibodies.”
Access of protective antiviral antibody to neuronal tissues requires CD4 T-cell help
Circulating antibodies can access most tissues to mediate surveillance and elimination of invading pathogens. Immunoprivileged tissues such as the brain and the peripheral nervous system are shielded from plasma proteins by the blood–brain barrier1 and blood–nerve barrier2, respectively. Yet, circulating antibodies must somehow gain access to these tissues to mediate their antimicrobial functions. Here we examine the mechanism by which antibodies gain access to neuronal tissues to control infection. Using a mouse model of genital herpes infection, we demonstrate that both antibodies and CD4 T cells are required to protect the host after immunization at a distal site. We show that memory CD4 T cells migrate to the dorsal root ganglia and spinal cord in response to infection with herpes simplex virus type 2. Once inside these neuronal tissues, CD4 T cells secrete interferon-γ and mediate local increase in vascular permeability, enabling antibody access for viral control. A similar requirement for CD4 T cells for antibody access to the brain is observed after intranasal challenge with vesicular stomatitis virus. Our results reveal a previously unappreciated role of CD4 T cells in mobilizing antibodies to the peripheral sites of infection where they help to limit viral spread.
T Cells Help Reverse Ovarian Cancer Drug Resistance
T cells (red) attack ovarian cancer cells (green). [University of Michigan Health System]
Researchers at the University of Michigan have recently published the results from a new study that they believe underscores why so many ovarian tumors develop resistance to chemotherapy. The tumor microenvironment is made up of an array of cell types, yet effector T cells and fibroblasts constitute the bulk of the tissue. The investigators believe that understanding the interplay between these two cell types holds the key to how ovarian cancer cells develop resistance.
The new study suggests that the fibroblasts surrounding the tumor work to block chemotherapy, which is why nearly every woman with ovarian cancer becomes resistant to treatment. Conversely, the scientists published evidence that T cells in the microenvironment can reverse the resistance phenotype—suggesting a whole different way of thinking about chemotherapy resistance and the potential to harness immunotherapy drugs to treat ovarian cancer.
“Ovarian cancer is often diagnosed at late stages, so chemotherapy is a key part of treatment,” explained co-senior study author J. Rebecca Liu, M.D., associate professor of obstetrics and gynecology at the University of Michigan. “Most patients will respond to it at first, but everybody develops chemoresistance. And that’s when ovarian cancer becomes deadly.”
Dr. Liu continued, stating that “in the past, we’ve thought the resistance was caused by genetic changes in tumor cells. But we found that’s not the whole story.”
The University of Michigan team looked at tissue samples from ovarian cancer patients and separated the cells by type to study the tumor microenvironment in vitro and in mice. More importantly, the scientists linked their findings back to actual patient outcomes.
The results of this study were published recently in Cell through an article entitled “Effector T Cells Abrogate Stroma-Mediated Chemoresistance in Ovarian Cancer.”
Ovarian cancer is typically treated with cisplatin, a platinum-based chemotherapy. The researchers found that fibroblasts blocked platinum. These cells prevented platinum from accumulating in the tumor and protected tumor cells from being killed off by cisplatin.
Diagram depicting how T cells can reverse chemotherapeutic resistance. [Cell, Volume 165, Issue 5, May 19, 2016]
“We show that fibroblasts diminish the nuclear accumulation of platinum in ovarian cancer cells, resulting in resistance to platinum-based chemotherapy,” the authors wrote. “We demonstrate that glutathione and cysteine released by fibroblasts contribute to this resistance.”
T cells, on the other hand, overruled the protection of the fibroblasts. When researchers added the T cells to the fibroblast population, the tumor cells began to die off.
“CD8+ T cells abolish the resistance by altering glutathione and cystine metabolism in fibroblasts,” the authors explained. “CD8+ T-cell-derived interferon (IFN)γ controls fibroblast glutathione and cysteine through upregulation of gamma-glutamyltransferases and transcriptional repression of system xc−cystine and glutamate antiporter via the JAK/STAT1 pathway.”
By boosting the effector T cell numbers, the researchers were able to overcome the chemotherapy resistance in mouse models. Moreover, the team used interferon, an immune cell-secreted cytokine, to manipulate the pathways involved in cisplatin.
“T cells are the soldiers of the immune system,” noted co-senior study author Weiping Zou, M.D., Ph.D., professor of surgery, immunology, and biology at the University of Michigan. “We already know that if you have a lot of T cells in a tumor, you have better outcomes. Now we see that the immune system can also impact chemotherapy resistance.”
The researchers suggest that combining chemotherapy with immunotherapy may be effective against ovarian cancer. Programmed death ligand 1 (PD-L1) and PD-1 pathway blockers are currently FDA-approved treatments for some cancers, although not ovarian cancer.
“We can imagine re-educating the fibroblasts and tumor cells with immune T cells after chemoresistance develops,” Dr. Zou remarked.
“Then we could potentially go back to the same chemotherapy drug that we thought the patient was resistant to. Only now we have reversed that, and it’s effective again,” Dr. Liu concluded.
Effector T Cells Abrogate Stroma-Mediated Chemoresistance in Ovarian Cancer
•Fibroblasts diminish platinum content in cancer cells, resulting in drug resistance
•GSH and cysteine released by fibroblasts contribute to platinum resistance
•T cells alter fibroblast GSH and cystine metabolism and abolish the resistance
•Fibroblasts and CD8+ T cells associate with patient chemotherapy response
Summary
Effector T cells and fibroblasts are major components in the tumor microenvironment. The means through which these cellular interactions affect chemoresistance is unclear. Here, we show that fibroblasts diminish nuclear accumulation of platinum in ovarian cancer cells, resulting in resistance to platinum-based chemotherapy. We demonstrate that glutathione and cysteine released by fibroblasts contribute to this resistance. CD8+ T cells abolish the resistance by altering glutathione and cystine metabolism in fibroblasts. CD8+ T-cell-derived interferon (IFN)γ controls fibroblast glutathione and cysteine through upregulation of gamma-glutamyltransferases and transcriptional repression of system xc− cystine and glutamate antiporter via the JAK/STAT1 pathway. The presence of stromal fibroblasts and CD8+ T cells is negatively and positively associated with ovarian cancer patient survival, respectively. Thus, our work uncovers a mode of action for effector T cells: they abrogate stromal-mediated chemoresistance. Capitalizing upon the interplay between chemotherapy and immunotherapy holds high potential for cancer treatment.
Activation of effect or T cells leads to increased glucose uptake, glycolysis, and lipid synthesis to support growth and proliferation. Activated T cells were identified with CD7, CD5, CD3, CD2, CD4, CD8 and CD45RO. Simultaneously, the expression of CD95 and its ligand causes apoptotic cells death by paracrine or autocrine mechanism, and during inflammation, IL1-β and interferon-1α.. The receptor glucose, Glut 1, is expressed at a low level in naive T cells, and rapidly induced by Myc following T cell receptor (TCR) activation. Glut1 trafficking is also highly regulated, with Glut1 protein remaining in intracellular vesicles until T cell activation. CD28 co-stimulation further activates the PI3K/Akt/mTOR pathway in particular, and provides a signal for Glut1 expression and cell surface localization. Mechanisms that control T cell metabolic reprogramming are now coming to light, and many of the same oncogenes importance in cancer metabolism are also crucial to drive T cell metabolic transformations, most notably Myc, hypoxia inducible factor (HIF)1a, estrogen-related receptor (ERR) a, and the mTOR pathway. The proto-oncogenic transcription factor, Myc, is known to promote transcription of genes for the cell cycle, as well as aerobic glycolysis and glutamine metabolism. Recently, Myc has been shown to play an essential role in inducing the expression of glycolytic and glutamine metabolism genes in the initial hours of T cell activation. In a similar fashion, the transcription factor (HIF)1a can up-regulate glycolytic genes to allow cancer cells to survive under hypoxic conditions
UPDATE 6/11/2021
Bispecific Antibodies Emerging as Effective Cancer Therapeutics
Science 28 May 2021: Vol. 372, Issue 6545, pp. 916-917 DOI: 10.1126/science.abg1209
Bispecific antibodies (bsAbs) bind two different epitopes on the same or different antigens. Through this dual specificity for soluble or cell-surface antigens, bsAbs exert activities beyond those of natural antibodies, offering numerous opportunities for therapeutic applications. Although initially developed for retargeting T cells to tumors, with a first bsAb approved in 2009 (catumaxomab, withdrawn in 2017), exploring new modes of action opened the door to many additional applications beyond those of simply combining the activity of two different antibodies within one molecule. Examples include agonistic “assembly activities” that mimic the activity of natural ligands and cofactors (for example, factor VIII replacement in hemophilia A), inactivation of receptors or ligands, and delivery of payloads to cells or tissues or across biological barriers. Over the past years, the bsAb field transformed from early research to clinical applications and drugs. New developments offer a glimpse into the future promise of this exciting and rapidly progressing field.
Monoclonal antibodies (mAbs) comprise antigen-binding sites formed by the variable domains of the heavy and light chain and an Fc region that mediates immune responses. BsAbs, produced through genetic engineering, combine the antigen-binding sites of two different antibodies within one molecule, with a plethora of formats available (1). Conceptually, one can discriminate between bsAbs with combinatorial modes of action where the antigen-binding sites act independently from each other, and bsAbs with obligate modes of action where activity needs binding of both, either in a sequential (temporal) way or dependent on the physical (spatial) linkage of both (see the figure) (2). BsAbs approved as drugs are so far in the obligate dual-binding category: A T cell recruiter (blinatumomab) against cancer and a factor VIIIa mimetic to treat hemophilia A (emicizumab). Most but not all of the more than 100 bsAbs in clinical development address cancers. Some are in late stage (such as amivantamab, epcoritamab, faricimab, and KNO46), but most are still in early stages (2). Most of these entities enable effector cell retargeting to induce target cell destruction.
An increasing number of programs also explore alternative modes of action. This includes bsAbs that target pathways involved in tumor proliferation (such as amivantamab), invasion, ocular angiogenesis (such as faricimab), or immune regulation by blocking receptors and/or ligands, mainly in a combinatorial manner. Challenges for all of these entities are potential adverse effects, toxicity in normal tissues, and overshooting and systemic immune responses, especially with T cell retargeting or immune-modulating or activating entities. Such issues need to be carefully addressed.
Most of the bispecific T cell engagers comprise a binding site for a tumor-associated antigen and CD3 [a component of the T cell receptor (TCR) activation complex] as trigger molecule on T cells. To prevent or ameliorate “on-target, off-tumor” effects of T cell recruiters, approaches currently investigated include the modulation of target affinities and mechanisms to allow conditional activation upon target cell binding. Thus, a reduced affinity for CD3 increased tolerability by reducing peripheral cytokine concentrations that are associated with nonspecific or overshooting immune reactions (3). Similarly, reduced affinity for the target antigen was shown to ameliorate cytokine release and damage of target-expressing tissues (4). Tumor selectivity can be further increased by implementing avidity effects—for example, by using 2+1 bsAb formats with two low-affinity binding sites for target antigens and monovalent binding to CD3 (4).
In further approaches, binders to CD3 were identified that efficiently trigger target cell destruction without inducing undesired release of cytokines, demonstrating the importance of epitope specificity to potentially uncouple efficacy from cytokine release (5). Complementing these T cell–recruiting principles, the nonclassical T cell subset of γ9d2 T cells with strong cytotoxic activity emerged as potent effectors, which can be retargeted with bsAbs binding to the γ9d2 TCR. Thereby, global activation of all T cells, including inhibitory regulatory T cells (Treg cells), through CD3 binding, may be avoided (6). However, even these approaches might result in a narrow therapeutic window to treat solid tumors because of T cell activation in normal tissues.
Consequently, there are several approaches to conditionally activate T cells within tumors, including a local liberation of the CD3-binding sites or triggering local assembly of CD3-binding sites from two half-molecules. For example, CD3-binding sites have been masked by fusing antigen binding or blocking moieties—such as peptides, aptamers, or anti-idiotypic antibody fragments—to one or both variable domains. These moieties are released within the tumor by tumor-associated proteases, or through biochemical responses to hypoxia or low pH (7). This approach can also be applied to confer specific binding of antibody therapeutics, including bsAbs, to antigens on tumor cells (8).
An on-target restoration of CD3-binding sites requires application of two target-binding entities, each comprising parts of the CD3-binding site, which assemble into functional binding sites upon close binding of both half-antibodies. The feasibility of this approach was recently shown, for example, for a split T cell–engaging antibody derivative (Hemibody) that targets a cell surface antigen (9). Such approaches can also be applied to half-antibodies that recognize two different targets expressed on the same cell, further increasing tumor selectivity.
Regarding T cell engagers, increasing efforts are made to target not only cell-surface antigens expressed on tumor cells but also human leukocyte antigen (HLA)–presented tumor-specific peptides. This expands the target space of bsAbs toward tumor-specific intracellular antigens and can be achieved by using either recombinant TCRs or antibodies with TCR-like specificities combined with, for example, CD3-binding arms to engage T cell responses. A first TCR–anti-CD3 bispecific molecule is in phase I and II trials to treat metastatic melanoma (10). A challenge of this approach is the identification of TCRs or TCR-like antibodies that bind the peptide in the context of HLA with high affinity and specificity, without cross-reacting with related peptides to reduce or avoid off-target activities. Comprehensive screening tools and implementation of computational approaches are being developed to achieve this task.
A rapidly growing area of bsAbs in cancer therapy is their use to foster antitumor immune responses. Here, they are especially applied for dual inhibition of checkpoints that prevent immune responses—for example, programmed cell death protein 1 (PD-1) and its ligand (PD-L1), cytotoxic T lymphocyte–associated antigen 4 (CTLA-4), or lymphocyte activation gene 3 (LAG-3; for example, KNO46). Tumor-targeted bsAbs can also target costimulatory factors such as CD28 or 4-1BB ligand (4-1BBL) to enhance T cell responses when combined with PD-1 blockade or to provide an activity-enhancing costimulatory signal in combination with CD3-based bsAbs (11). Furthermore, bsAbs are being developed for local effects by targeting one arm to antigens that are expressed by tumor cells or cells of the tumor microenvironment (2).
Clinical application of bsAbs now expands to other therapeutic areas, including chronic inflammatory, autoimmune, and neurodegenerative diseases; vascular, ocular, and hematologic disorders; and infections. In contrast to mAbs, bsAbs can inactivate the signaling of different cytokines with one molecule to treat inflammatory diseases (12). Simultaneous dual-target binding is not essential to elicit activity for bsAbs against combinations of proinflammatory cytokines, such as tumor necrosis factor (TNF), interleukin-1α (IL-1α), IL-1β, IL-4, IL-13, IL-17, inducible T cell costimulator ligand (ICOSL), or B cell–activating factor (BAFF). This presumably also applies to blockade of immune cell receptors, although dual targeting might confer increased efficacy due to avidity effects and increased selectivity through simultaneous binding of two different receptors.
A further application of combinatorial dual targeting is in ophthalmology. Loss of vision in wet age-related macular degeneration (AMD) results from abnormal proliferation and leakiness of blood vessels in the macula. This can be treated with antibodies that bind and inactivate factors that stimulate their proliferation (13). In contrast to mAbs or fragments that recognize individual factors, bsAbs bind two such factors. For example, faricimab that binds vascular endothelial growth factor A (VEGF-A) and angiopoietin-2 (ANG2), demonstrated dual efficacy in preclinical studies, and is currently in phase 3 trials.
BsAbs with obligate modes of action that mandate simultaneous dual-target binding are “assemblers” that replace the function of factors necessary to form functional protein complexes. One of these bsAbs with an assembly role (emicizumab, approved in 2018) replaces factor VIIIa in the clotting cascade. Deficiency of factor VIII causes hemophilia A, which can be overcome by substitution with recombinant factor VIII. However, a proportion of patients develop factor VIII–neutralizing immune responses and no longer respond to therapy. To overcome this, a bsAb was developed with binding sites that recognize and physically connect factors IXa and X, a process normally mediated by factor VIIIa. Extensive screening of a large set of bsAbs was required to identify those that combine suitable epitopes with optimized affinities and geometry to serve as functional factor VIIIa mimetics (14). This exemplifies the complexity of identifying the best bsAb for therapeutic applications.
A mode of action requiring sequential binding of two targets is the transport of bsAbs across the blood-brain barrier (BBB). This is a tight barrier of brain capillary endothelial cells that controls the transport of substances between the blood and the cerebrospinal fluid—the brain parenchyma. Passage of large molecules, including antibodies, across the BBB is thereby restricted. Some proteins, such as transferrin or insulin, pass through the BBB by way of transporters on endothelial cells. Antibodies that bind these shuttle molecules, such as the transferrin receptor (TfR), can hitchhike across the BBB. BsAbs that recognize brain targets (such as β-amyloid for Alzheimer’s disease) and TfR with optimized affinities, epitopes, and formats can thereby enter the brain. Such bsAbs are currently in clinical evaluation to treat neurodegenerative diseases (15).
In the past years, there has been a transition from a technology-driven phase, solving hurdles to generate bsAbs with defined composition, toward exploring and extending the modes of action for new therapeutic options. The challenge of generating bsAbs is not only to identify suitable antigen pairs to be targeted in a combined manner. It is now recognized that the molecular composition has a profound impact on bsAb functionality (13). That more than 30 different bsAb formats are in clinical trials proves that development is now driven by a “fit for purpose” or “format defines function” rationale. Many candidates differ in their composition, affecting valency, geometry, flexibility, size, and half-life (1). Not all members of this “zoo of bsAb formats” qualify to become drugs. Strong emphasis is therefore on identifying candidates that exhibit drug-like properties and fulfill safety, developability, and manufacturability criteria. There is likely to be an exciting new wave of bsAb therapeutics available in the coming years.
2012pharmaceutical
Amandeep Kaur
Aashir Awan, Phd
Abhisar Anand
Adina Hazan
Alan F. Kaul, PharmD., MS, MBA, FCCP
alexcrystal6
anamikasarkar
apreconasia
aptubman
Arav Gandhi
aviralvatsa
David Orchard-Webb, PhD
danutdaagmailcom
Demet Sag, Ph.D., CRA, GCP
Dror Nir
dsmolyar
Ethan Coomber
evelinacohn
FrasonKalapurackal
Gail S Thornton
Irina Robu
jayzmit48
jdpmd
jshertok
kellyperlman
Ed Kislauskis
larryhbern
Madison Davis
marzankhan
megbaker58
ofermar2020
Dr. Pati
pkandala
ritusaxena
Rick Mandahl
sjwilliamspa
Srinivas Sriram
stuartlpbi
Dr. Sudipta Saha
tildabarliya
zraviv06
zs2230489-X&id=fx1.jpg){kind=link}
