Archive for the ‘immunology’ Category

Reporter and Curator: Dr. Sudipta Saha, Ph.D.

During pregnancy, the baby is mostly protected from harmful microorganisms by the amniotic sac, but recent research suggests the baby could be exposed to small quantities of microbes from the placenta, amniotic fluid, umbilical cord blood and fetal membranes. One theory is that any possible prenatal exposure could ‘pre-seed’ the infant microbiome. In other words, to set the right conditions for the ‘main seeding event’ for founding the infant microbiome.

When a mother gives birth vaginally and if she breastfeeds, she passes on colonies of essential microbes to her baby. This continues a chain of maternal heritage that stretches through female ancestry for thousands of generations, if all have been vaginally born and breastfed. This means a child’s microbiome, that is the trillions of microorganisms that live on and in him or her, will resemble the microbiome of his/her mother, the grandmother, the great-grandmother and so on, if all have been vaginally born and breastfed.

As soon as the mother’s waters break, suddenly the baby is exposed to a wave of the mother’s vaginal microbes that wash over the baby in the birth canal. They coat the baby’s skin, and enter the baby’s eyes, ears, nose and some are swallowed to be sent down into the gut. More microbes form of the mother’s gut microbes join the colonization through contact with the mother’s faecal matter. Many more microbes come from every breath, from every touch including skin-to-skin contact with the mother and of course, from breastfeeding.

With formula feeding, the baby won’t receive the 700 species of microbes found in breast milk. Inside breast milk, there are special sugars called human milk oligosaccharides (HMO’s) that are indigestible by the baby. These sugars are designed to feed the mother’s microbes newly arrived in the baby’s gut. By multiplying quickly, the ‘good’ bacteria crowd out any potentially harmful pathogens. These ‘good’ bacteria help train the baby’s naive immune system, teaching it to identify what is to be tolerated and what is pathogen to be attacked. This leads to the optimal training of the infant immune system resulting in a child’s best possible lifelong health.

With C-section birth and formula feeding, the baby is not likely to acquire the full complement of the mother’s vaginal, gut and breast milk microbes. Therefore, the baby’s microbiome is not likely to closely resemble the mother’s microbiome. A baby born by C-section is likely to have a different microbiome from its mother, its grandmother, its great-grandmother and so on. C-section breaks the chain of maternal heritage and this break can never be restored.

The long term effect of an altered microbiome for a child’s lifelong health is still to be proven, but many studies link C-section with a significantly increased risk for developing asthma, Type 1 diabetes, celiac disease and obesity. Scientists might not yet have all the answers, but the picture that is forming is that C-section and formula feeding could be significantly impacting the health of the next generation. Through the transgenerational aspect to birth, it could even be impacting the health of future generations.



















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The Strategy of Precision Editing the Cancer Cell Glycocalyx using an “antibody–enzyme conjugate” for Cancer Immunotherapy: Research Beyond “augment the activator or remove inhibitor, or both”

Reporter: Aviva Lev-Ari, PhD, RN


Successful tumors are able to evade the immune system, which is otherwise capable of killing transformed cells. Therapies that prevent this evasion have become revolutionary treatments for incurable cancers. One mechanism of evasion is the presentation of sugars, called sialic acids, within the cell surface’s sugar coating, or glycocalyx. Here, we designed biotherapeutic molecules, termed “antibody–enzyme conjugates,” that selectively remove sialic acids from tumor cells. The antibody directs the enzyme to the cancer cells, the enzyme cleaves the sugars, and then the antibody directs immune cells to kill the desialylated cancer cells. The conjugate increased tumor cell killing compared with the antibody alone. Editing the cancer cell glycocalyx with an antibody–enzyme conjugate represents a promising approach to cancer immune therapy.



AUGUST 22, 2016

Stanford chemists develop a new method of cancer immunotherapy

A team of Stanford ChEM-H scientists has discovered a novel form of cancer immunotherapy, which works by removing certain sugars from the surface of cancer cells and making those cells visible to the immune system.

“All of the world of immune therapy is now thinking about the immune system as calculating pluses and minuses. If you want to tilt the scale toward immune activation, you can either augment the activator or remove inhibitor, or both,” said Bertozzi, who is also an investigator with the Howard Hughes Medical Institute.

Current immunotherapies on the market work by blocking one of the inhibitory signals that are recognized by the adaptive immune system. Block those and the balance tilts in such a way that the immune system will attack the now recognizable cancer.

Bertozzi’s approach provides a second way of tiling the balance in favor of attack, this time for the innate immune system. She said this study shows just one example of how it could work, but her sugar-removing lawnmower could be used on a wide variety of cell types, not just those expressing HER2, and on different types of sugars.

“It’s almost always the case that you need a component of both the adaptive and innate immunity to get a robust reaction against infectious pathogens, such as during vaccination,” said Bertozzi. “The smart money suggests that the same will be true with tumors.”

Bertozzi said the approach also highlights the importance of paying attention to the much ignored glycocalyx.


Stanford chemists develop a new method of cancer immunotherapy




A symbolic representation of a glycocalyx chain attached to a cytoskeleton.

IMAGE SOURCE: google images



image glycocalyx

IMAGE SOURCE: google images


Glycocalyx – www.futura-sciences.us576 × 284Search by image

The carbohydrates, glycoproteins and proteoglycans making up the glycocalyx

IMAGE SOURCE: google images

PNAS – Original Article

Precision glycocalyx editing as a strategy for cancer immunotherapy

  1. Han Xiaoa,b,1,
  2. Elliot C. Woodsa,b,1,
  3. Petar Vukojicica,b, and
  4. Carolyn R. Bertozzia,b,2
  1. Edited by Laura L. Kiessling, University of Wisconsin-Madison, Madison, WI, and approved July 11, 2016 (received for review May 24, 2016)


Cell surface sialosides constitute a central axis of immune modulation that is exploited by tumors to evade both innate and adaptive immune destruction. Therapeutic strategies that target tumor-associated sialosides may therefore potentiate antitumor immunity. Here, we report the development of antibody–sialidase conjugates that enhance tumor cell susceptibility to antibody-dependent cell-mediated cytotoxicity (ADCC) by selective desialylation of the tumor cell glycocalyx. We chemically fused a recombinant sialidase to the human epidermal growth factor receptor 2 (HER2)-specific antibody trastuzumab through a C-terminal aldehyde tag. The antibody–sialidase conjugate desialylated tumor cells in a HER2-dependent manner, reduced binding by natural killer (NK) cell inhibitory sialic acid-binding Ig-like lectin (Siglec) receptors, and enhanced binding to the NK-activating receptor natural killer group 2D (NKG2D). Sialidase conjugation to trastuzumab enhanced ADCC against tumor cells expressing moderate levels of HER2, suggesting a therapeutic strategy for cancer patients with lower HER2 levels or inherent trastuzumab resistance. Precision glycocalyx editing with antibody–enzyme conjugates is therefore a promising avenue for cancer immune therapy.


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Inotuzumab Ozogamicin: Success in relapsed/refractory Acute Lymphoblastic Leukemia (ALL)

Reporter: Aviva Lev-Ari, PhD, RN


About Inotuzumab Ozogamicin

Inotuzumab ozogamicin is an investigational antibody-drug conjugate (ADC) comprised of a monoclonal antibody (mAb) targeting CD22,9 a cell surface antigen expressed on approximately 90 percent of B-cell malignancies,10 linked to a cytotoxic agent. When inotuzumab ozogamicin binds to the CD22 antigen on malignant B-cells, it is internalized into the cell, where the cytotoxic agent calicheamicin is released to destroy the cell.11

Inotuzumab ozogamicin originates from a collaboration between Pfizer and Celltech, now UCB. Pfizer has sole responsibility for all manufacturing, clinical development and commercialization activities for this molecule.

Acute lymphoblastic leukemia (ALL)

is an aggressive type of leukemia with high unmet need and a poor prognosis in adults.4The current standard treatment is intensive, long-term chemotherapy.5 In 2015, it is estimated that 6,250 cases of ALL will be diagnosed in the United States6, with about 1 in 3 cases in adults. Only approximately 20 to 40 percent of newly diagnosed adults with ALL are cured with current treatment regimens.7 For patients with relapsed or refractory adult ALL, the five-year overall survival rate is less than 10 percent.8


1 Fielding A. et al. Outcome of 609 adults after relapse of acute lymphoblastic leukemia (ALL); an MRC UKALL12/ECOG 2993 study. Blood. 2006; 944-950.

2 U.S. Food and Drug Administration Safety and Innovation Act. Available at: http://www.gpo.gov/fdsys/pkg/PLAW-112publ144/pdf/PLAW-112publ144.pdf(link is external).Accessed July 11, 2015.

3 U.S. Food and Drug Administration Frequently Asked Questions: Breakthrough Therapies. Available at:http://www.fda.gov/RegulatoryInformation/Legislation/FederalFoodDrugandCosmeticActFDCAct/SignificantAmendmentstotheFDCAct/FDASIA/ucm341027.htm(link is external). Accessed July 11, 2015.

4 National Cancer Institute: Adult Acute Lymphoblastic Leukemia Treatment (PDQ®) – General Information About Adult Acute Lymphoblastic Leukemia (ALL). Available at:http://www.cancer.gov/cancertopics/pdq/treatment/adultALL/HealthProfessional/page1(link is external). Accessed July 11, 2015.

5 American Cancer Society: Typical treatment of acute lymphocytic leukemia. Available at:http://www.cancer.org/cancer/leukemia-acutelymphocyticallinadults/detailedguide/leukemia-acute-lymphocytic-treating-typical-treatment(link is external). Accessed July 11, 2015.

6 American Cancer Society: What are the key statistics about acute lymphocytic leukemia? Available at:http://www.cancer.org/cancer/leukemia-acutelymphocyticallinadults/detailedguide/leukemia-acute-lymphocytic-key-statistics(link is external). Accessed February 18, 2015.

7 Manal Basyouni A. et al. Prognostic significance of survivin and tumor necrosis factor-alpha in adult acute lymphoblastic leukemia. doi:10.1016/j.clinbiochem.2011.08.1147.

8 Fielding A. et al. Outcome of 609 adults after relapse of acute lymphoblastic leukemia (ALL); an MRC UKALL12/ECOG 2993 study. Blood. 2006; 944-950.

9 Clinicaltrials.gov. A Study of Inotuzumab Ozogamicin versus Investigator’s Choice of Chemotherapy in Patients with Relapsed or Refractory Acute Lymphoblastic Leukemia. Available at: http://www.clinicaltrials.gov/ct2/show/NCT01564784?term=inotuzumab&rank=7(link is external). Accessed July 11, 2015.

10 Leonard J et al. Epratuzumab, a Humanized Anti-CD22 Antibody, in Aggressive Non-Hodgkin’s Lymphoma: a Phase I/II Clinical Trial Results. Clinical Cancer Research. 2004; 10: 5327-5334.

11 DiJoseph JF. Antitumor Efficacy of a Combination of CMC-544 (Inotuzumab Ozogamicin), a CD22-Targeted Cytotoxic Immunoconjugate of Calicheamicin, and Rituximab against Non-Hodgkin’s B-Cell Lymphoma. Clin Cancer Res. 2006; 12: 242-250.



Other related article Published on this Open Access Online Scientific Journal include the following:


Nicole L. Gularte, MBA



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Pathophysiology in Hypertension: Opposing Roles of Human Adaptive Immunity

Reporter: Aviva Lev-Ari, PhD, RN

T regulatory lymphocytes counteract hypertensive effects by suppressing innate and adaptive immune responses and T effector lymphocytes promote differentiation towards pro-inflammatory T helper cells


Dual opposing roles of adaptive immunity in hypertension

, , ,

DOI: http://dx.doi.org/10.1093/eurheartj/ehu119 1238-1244 First published online: 30 March 2014


Hypertension involves remodelling and inflammation of the arterial wall. Interactions between vascular and inflammatory cells play a critical role in disease initiation and progression. T effector and regulatory lymphocytes, members of the adaptive immune system, play contrasting roles in hypertension. Signals from the central nervous system and the innate immune system antigen-presenting cells activate T effector lymphocytes and promote their differentiation towards pro-inflammatory T helper (Th) 1 and Th17 phenotypes. Th1 and Th17 effector cells, via production of pro-inflammatory mediators, participate in the low-grade inflammation that leads to blood pressure elevation and end-organ damage. T regulatory lymphocytes, on the other hand, counteract hypertensive effects by suppressing innate and adaptive immune responses. The present review summarizes and discusses the adaptive immune mechanisms that participate in the pathophysiology in hypertension.

  • Blood pressure
  • Adaptive immunity
  • Inflammation
  • T effector lymphocytes
  • T regulatory lymphocytes
  • Cytokines


Experimental and clinical evidence discussed in this review strongly suggests that adaptive immunity, represented by T effector and regulatory lymphocyte subsets, plays a dual role in hypertension (Figure 2). Increased sympathetic outflow as a consequence of stimulation of the CNS by hypertensive stimuli may result in mild blood pressure elevation, causing tissue injury and formation of neoantigens2 and/or damage-associated molecular patterns (DAMPs).80 Activation of innate APCs by DAMPs, or by pathogen-associated molecular patterns (PAMPs) generated in response to low-grade infection,80,81 and direct stimulation by CNS, may be the cause of activation of CD4+, and perhaps CD8+, T effector lymphocytes, and differentiation of CD4+ T cells towards pro-inflammatory Th1/Th17 phenotypes.41 Th1/Th17 effector lymphocytes contribute to the progression of hypertension by producing pro-inflammatory mediators, including ROS, IFN-γ, TNF-α, and IL-17, to promote low-grade inflammation.24,41,42,51,52 T regulatory lymphocytes, on the other hand, counteract hypertensive abnormalities by suppressing innate and adaptive immune responses, perhaps by secreting IL-10.6571 As such, circulating levels of Tregs or their immune-suppressive activity may be affected in hypertension.



Idris-Khodja et al. (2014) Dual opposing roles of adaptive immunity in hypertension. European Heart Journal (doi: 10.1093/eurheartj/ehu119)


Adaptive Immunity

Figure 1

Differentiation of naïve T lymphocytes into various subsets in a normal immune response. Antigen-presenting cells (dendritic cells and monocyte/macrophages) present antigens on major histocompatibility complex (MHC)-II to naïve T cells (Th0) in secondary lymphoid tissues, leading to T-cell clonal expansion and differentiation into effector T cells, such as T helper (Th)1, Th2, and Th17 or T regulatory (Treg) cells according to combined stimulation by different cytokines. Th effector lymphocytes and Tregs migrate into tissues such as the vasculature, particularly at the level of the adventitia and perivascular fat. The effector lymphocytes (Th1 and Th17) cells activate other immune cells and participate in inflammation by producing pro-inflammatory cytokines such as interferon-γ, interleukin (IL)-6, and IL-17. T regulatory lymphocytes suppress innate and adaptive responses via production of anti-inflammatory cytokines IL-10 and transforming growth factor-β. CD, cluster of differentiation; DC, dendritic cell; MΦ, macrophage; NK cell, natural killer cell; Tc, cytotoxic T cell; TCR, T-cell receptor.








Figure 2

Proposed role of T effector and regulatory lymphocytes in hypertension. Slight elevation in blood pressure (BP) in response to hypertensive stimuli (angiotensin II, aldosterone, endothelin-1, salt and genetic susceptibility) occurs due to increased central signalling, perhaps causing mild tissue injury and formation of damage-associated molecular patterns (DAMPs) and neoantigens. This may lead to activation of innate antigen-presenting cells (APCs) and, subsequently, activation and polarization of naïve CD4+ T effector lymphocytes (Th0) towards pro-inflammatory T helper (Th)1/Th17 phenotypes. Th1/Th17 may contribute to vascular and kidney damage via production of reactive oxygen species (ROS), interferon (IFN)-γ and interleukin (IL)-17 and lead to maintenance of hypertension and progression of end-organ damage. T regulatory lymphocytes counteract hypertension and associated injury by producing IL-10 or by other mechanisms, and suppression of innate and adaptive immune responses. CD, cluster of differentiation; CNS, central nervous system; MHC-II, major histocompatibility complex-II; PAMPs, pathogen-associated molecular patterns; TCR, T-cell receptor.

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CHI’s NK Cell-Based Cancer Immunotherapy Symposium, September 19 in Boston

Reporter: Aviva Lev-Ari, PhD, RN


Announcement from LPBI Group: key code LPBI16 for Exclusive Discount to attend Boston’s Discovery on Target (September 2016)





Natural killer (NK) cells have been known to have advantages over T cells, yet their therapeutic potential in the clinic has been largely unexplored.

Cambridge Healthtech Institute’s NK Cell-Based Cancer Immunotherapy Symposium, September 19 in Boston, is dedicated to the exploration of utilizing NK cells for new adoptive cell therapies, including updates from ongoing clinical studies.


Harnessing Adaptive NK Cells in Cancer Therapy

Karl-Johan Malmberg, M.D., Ph.D., Professor, Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital

  • We have recently completed a Phase I/II clinical trial with transfer of haploidentical NK cells to patients with high-risk myelodysplastic syndrome. Six of the 16 treated patients achieved morphological complete remission and five of these underwent allogeneic stem cell transplantation resulting in long-term survival in four patients. The quality and number of infused NK cells as well as their transient engraftment in the recipient correlated with decrease in mutational burden and clinical outcomes. These results suggest that adoptive transfer of allogeneic NK cells may hold utility as a bridge to transplant in patients who are refractory to induction therapy. Current efforts to selectively expand metabolically optimized adaptive NK cells for the next generation NK cell cancer immunotherapy will be discussed.

Update on Systemic and Locoregional Cancer Immunotherapy with IL-21-Expanded NK Cells

Dean Anthony Lee, M.D., Ph.D., Professor, Pediatrics; Director, Cellular Therapy and Cancer Immunotherapy Program, Nationwide Children’s Hospital; James Comprehensive Cancer Center/Solove Research Institute, The Ohio State University

  • The ability to generate clinical-grade NK cell products of sufficient purity, number, and function has enabled broader application of adoptive NK cell therapy in clinical trials. We translated our IL-21-based NK cell expansion platform to clinical grade and scale and initiated 7 clinical trials that administer NK cell immunotherapy with high cell doses or repeated dosing in transplant, adjuvant, or stand-alone settings. These trials have collectively delivered approximately 150 infusions to over 60 patients at doses of up to 10e8/kg. We will discuss the importance of STAT3 signaling in this setting, describe early outcome and correlative data from these studies, and present preclinical data supporting future clinical trials that build on this platform.







Suggested Event Package


NK Cell-Based Cancer Immunotherapy

SEPT. 19


Antibodies Against Membrane Protein Targets (Part One)

SEPT. 20-21


Antibodies Against Membrane Protein Targets (Part Two)

SEPT. 21-22

The exhibit hall was sold out in 2015, so please contact us early to reserve your place. To customize your sponsorship or exhibit package for 2016, contact:

Jon Stroup

Sr. Business Development Manager

P: 781-972-5483

E: jstroup@healthtech.com

Sponsorship/Exhibitor Information >>


DiscoveryOnTarget.com | Register by August 12 to SAVE up to $200 | Download PDF Agenda

Cambridge Healthtech Institute | 250 First Avenue, Suite 300, Needham, MA 02494 | www.healthtech.com | 781-972-5400


From: NK Cell Symposium <heidio@healthtech.com>

Date: Tuesday, August 9, 2016 at 1:40 PM

To: Aviva Lev-Ari <AvivaLev-Ari@alum.berkeley.edu>

Subject: NK Cells for Adoptive Therapies: The Future of Cancer Immunotherapy?

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Another Promise for Immune Oncology

Curator: Larry H. Berstein, MD, FCAP



Preclinical Data Presented at ASCO 2016 Annual Meeting Demonstrate that Single-Agent NKTR-214 Produces a Large Increase in Tumor-Infiltrating Lymphocytes to Provide Durable Anti-Tumor Activity


SAN FRANCISCO, June 6, 2016 /PRNewswire/ — Nektar Therapeutics (NASDAQ: NKTR) today announced new preclinical data for NKTR-214, an immuno-stimulatory CD-122 biased cytokine currently being evaluated in cancer patients with solid tumors in a Phase 1/2 clinical trial being conducted at MD Anderson Cancer Center and Yale Cancer Center. The new preclinical data presented demonstrate that treatment with single-agent NKTR-214 mobilizes tumor-killing T cells into colon cancer tumors.  In addition, mouse pharmacodynamics data demonstrated that a single dose of NKTR-214 can increase and sustain STAT5 phosphorylation (a marker of IL-2 pathway activation) through one week post-dose. These data were presented at the American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, IL from June 3-7, 2016.

“These latest data build upon our growing body of preclinical evidence demonstrating the unique mechanism of NKTR-214,” added Jonathan Zalevsky, PhD, Vice President, Biology and Preclinical Development at Nektar Therapeutics. “The studies presented at ASCO show that NKTR-214 promotes tumor-killing immune cell accumulation directly in the tumor, providing a mechanistic basis for its significant anti-tumor activity in multiple preclinical tumor models.  The ability to grow TILs1 in vivo and replenish the immune system is exceptionally important. We’ve now learned that many human tumors lack sufficient TIL populations and the addition of the NKTR-214 TIL-enhancing MOA could improve the success of many checkpoint inhibitors and other agents, and allow more patients to benefit from immuno-therapy.”

In studies previously published for NKTR-214, when mice bearing established breast cancer tumors are treated with NKTR-214 and anti-CTLA4 (a checkpoint inhibitor therapy known as ipilimumab for human treatment), a large proportion of mice become tumor-free. Anti-tumor immune memory was demonstrated when tumor-free mice were re-challenged by implant with a new breast cancer tumor and then found to clear the new tumor, without further therapy.  The new data presented at ASCO demonstrate that upon re-challenge, there is a rapid expansion of newly proliferative CD8 T cells and particularly CD8 effector memory T cells. Both cell populations were readily detectable in multiple tissues (blood, spleen, and lymph nodes) and likely contribute to the anti-tumor effect observed in these animals. Adoptive transfer studies confirmed the immune-memory effect as transplant of splenocytes from tumor-free mice into naïve recipients provided the ability to resist tumor growth.

“NKTR-214 provides a highly unique immune activation profile that allows it to access the IL-2 pathway without pushing the immune system into pathological overdrive,” said Dr. Steve Doberstein, Senior Vice President and Chief Scientific Officer. “NKTR-214’s unique immune-stimulatory profile and antibody-like dosing schedule positions it as a potentially important medicine within the immuno-oncology landscape.”

The data presentation at ASCO entitled, “Immune memory in nonclinical models after treatment with NKTR-214, an engineered cytokine biased towards expansion of CD8+ T cells in tumor,” can be accessed at http://www.nektar.com/2016_NKTR-214_ASCO_poster.pdf

NKTR-214 is a CD122-biased agonist designed to stimulate the patient’s own immune system to kill tumor cells by preferentially activating production of specific immune cells which promote tumor killing, including CD8-positive T cells and Natural Killer (NK) cells, within the tumor micro-environment.  CD122, which is also known as the Interleukin-2 receptor beta subunit, is a key signaling receptor that is known to increase proliferation of these types of T cells.2

In preclinical studies, NKTR-214 demonstrated a highly favorable mean ratio of 450:1 within the tumor micro-environment of CD8-positive effector T cells relative to regulatory T cells.3 Furthermore, the pro-drug design of NKTR-214 enables an antibody-like dosing regimen for an immuno-stimulatory cytokine.4

About the NKTR-214 Phase 1/2 Clinical Study
A Phase 1/2 clinical study is underway to evaluate NKTR-214 in patients with advanced solid tumors, including melanoma, renal cell carcinoma and non-small cell lung cancer. The first stage of this study, which is expected to be complete in the second half of 2016, is evaluating escalating doses of single-agent NKTR-214 treatment in approximately 20 patients with solid tumors. The primary objective of the first stage of the study is to evaluate the safety and efficacy of NKTR-214 and to identify a recommended Phase 2 dose. In addition, the study will also assess the immunologic effect of NKTR-214 on TILs and other immune cells in both blood and tumor tissue, and it will also include TCR repertoire profiling. Dose expansion cohorts are planned to evaluate NKTR-214 in specific tumor types, including melanoma, renal cell carcinoma and non-small cell lung cancer.

The NKTR-214 clinical study is being conducted initially at two primary investigator sites: MD Anderson Cancer Center under Drs. Patrick Hwu and Adi Diab; and Yale Cancer Center, under Drs. Mario Sznol and Michael Hurwitz.  Patients and physicians interested in the ongoing NKTR-214 study can visit the “Clinical Trials” section of www.mdanderson.org using identifier 2015-0573 or visit https://medicine.yale.edu/cancer/research/trials/active/858.trial.

About Nektar
Nektar Therapeutics has a robust R&D pipeline and portfolio of approved partnered medicines in oncology, pain, immunology and other therapeutic areas. In the area of oncology, Nektar is developing NKTR-214, an immuno-stimulatory CD122-biased agonist, that is in Phase 1/2 clinical development for patients with solid tumors. ONZEALD™ (etirinotecan pegol), a long-acting topoisomerase I inhibitor, is being developed for patients with advanced breast cancer and brain metastases and is partnered with Daiichi Sankyo in Europe.  In the area of pain, Nektar has an exclusive worldwide license agreement with AstraZeneca for MOVANTIK™ (naloxegol), the first FDA-approved once-daily oral peripherally-acting mu-opioid receptor antagonist (PAMORA) medication for the treatment of opioid-induced constipation (OIC), in adult patients with chronic, non-cancer pain. The product is also approved in the European Union as MOVENTIG® (naloxegol) and is indicated for adult patients with OIC who have had an inadequate response to laxatives. The AstraZeneca agreement also includes NKTR-119, an earlier stage development program that is a co-formulation of MOVANTIK and an opioid. NKTR-181, a wholly owned mu-opioid analgesic molecule for chronic pain conditions, is in Phase 3 development. In hemophilia, Nektar has a collaboration agreement with Baxalta for ADYNOVATE™ [Antihemophilic Factor (Recombinant)], a longer-acting PEGylated Factor VIII therapeutic approved in the U.S. and Japan for patients over 12 with hemophilia A. In anti-infectives, the company has two collaborations with Bayer Healthcare, Cipro Inhale in Phase 3 for non-cystic fibrosis bronchiectasis and Amikacin Inhale in Phase 3 for patients with Gram-negative pneumonia.

Immune memory in nonclinical models after treatment with NKTR-214, an engineered cytokine biased towards expansion of CD8+ T cells in tumor

Deborah H. Charych, Vidula Dixit, Peiwen Kuo, Werner Rubas, Janet Cetz, Rhoneil Pena, John L. Langowski, Ute Hoch, Murali Addepalli, Stephen K. Doberstein, Jonathan Zalevsky | Nektar Therapeutics, San Francisco, CA


• Recombinant human IL-2 (aldesleukin) is an effective immunotherapy for metastatic melanoma and renal cell carcinoma with durable responses in ~ 10% of patients, but side effects limit its use

• IL-2 has pleiotropic immune modulatory effects[1] which may limit its anti-tumor activity

• Binding to the heterodimeric receptor IL-2Rβγ leads to expansion of tumor-killing CD8+ memory effector T cells and NK cells

• Binding to the heterotrimeric IL-2Rαβγ leads to expansion of suppressive Treg which antagonizes anti-tumor immunity

• NKTR-214 delivers a controlled, sustained and biased signal through the IL-2 receptor pathway.

• The prodrug design of NKTR-214 comprises recombinant human IL-2 chemically conjugated with multiple releasable chains of polyethylene glycol (PEG)

• Slow release of PEG chains over time generates active PEG-conjugated IL-2 metabolites of increasing bioactivity, improving pharmacokinetics and tolerability compared to aldesleukin

• Active NKTR-214 metabolites bias IL-2R activation towards CD8 T cells over Treg[2]


NKTR-214 was engineered to release PEG at physiological pH with predictable kinetics.

The kinetics of PEG release was evaluated in vitro by quantifying free PEG over time using HPLC.

The release of PEG from IL-2 followed predictable kinetics. Symbols = measured data; Line = curve fit based on first order kinetic model. R2 =0.997


In mice, a single dose of NKTR-214 gradually builds and sustains pSTAT5 levels through seven days post-dose. In contrast, IL-2 produces a rapid burst of pSTAT5 that declines four hours post-dose

C57BL/6 mice were treated with either one dose of NKTR-214 (blue) or aldesleukin (red); blood samples were collected at various time points post-dose. pSTAT5 in peripheral blood CD3+ T cells was assessed using flow cytometry. Top graph is an inset showing the 0-4 hour time period. Bottom graph shows the full 10 day time course of the experiment. Histograms on right depict pSTAT5 MFI for IL-2 (red) and NKTR-214 (blue)


Mobilization of lymphocytes from the periphery into the tumor is an inherent property of NKTR-214

A. C57BL/6 mice bearing established subcutaneous B16F10 melanoma tumors were dosed with either NKTR-214 (2 mg/kg, i.v., q9d x2) or aldesleukin (3 mg/kg, i.p. bid x5, two cycles)

B. Tumor infiltrating lymphocytes were analyzed by flow cytometry from treated tumors (*, p<0.05 relative to vehicle; ‡, p<0.05 relative to aldesleukin)

C. Tumor growth inhibition from NKTR-214 was compromised when NKTR-214 was co-administered with Fingolimod, an agent that blocks lymphocyte trafficking.[3], (C57BL/6 mice, B16F10 subcutaneous mouse melanoma). Fingolimod was dosed qd p.o. 5 ug/animal. Lymphocyte count in blood was significantly reduced as expected, for study duration. Tumor growth inhibition (TGI) shown at study endpoint. (One-way ANOVA, Dunnets multiple comparison test ***=p<0.001, ****=p<0.0001 vs. vehicle; #=p<0.05 vs. NKTR-214)

D. Balb/c mice bearing established subcutaneous CT26 colon tumors were dosed with NKTR-214, 0.8 mg/kg i.v. q9dx3 or checkpoint inhibitors, 200 ug/mouse 2x/week. (*, p<0.05 relative to vehicle) E. T cell infiltration into mouse CT26 colon tumors was determined by TIL DNA fraction 7 days post-dose, Adaptive Biotechnologies, n=4 per group


The combination of NKTR-214 and anti-CTLA4 delivers durable anti-tumor activity and vigorous immune memory recall Durable treatment-induced immune memory demonstrated by:

A. Rejection of new tumors implanted into tumor-free mice without further therapy,

Durable anti-tumor immune memory demonstrated by rechallenging treated tumor-free mice with new tumors. New tumors can be eliminated without further treatment.

Balb/c mice initially were implanted with EMT6 murine breast tumors and treated with NKTR-214 0.8mg/kg q9dx3 and anti-CTLA4 200ug/mouse 2x/week. Several weeks later, tumor-free mice were rechallenged with tumor cells EMT6 (blue), CT26 (red) or vehicle (black). Tumor outgrowth occurred when non-related CT26 tumors were implanted. In contrast, tumors were rejected by up to 100% of mice when the same EMT6 tumors were implanted (2×106 EMT6 or CT26 cells)

B. Production of proliferating CD8 effector memory T cells in 3 tissues after tumor rechallenge and

Durable anti-tumor immune memory demonstrated by vigorous proliferative (Ki67+) CD8 T cell responses. The increased activity of these cells is greatest for mice previously treated with NKTR-214 and anti-CTLA4, rechallenged with the same tumor type (blue) compared to a different tumor (red) or mice who were never treated (brown, gray). Treated mice received therapy ~6 months prior. Top row shows total CD8+ cells, bottom row shows effector memory CD8+ in 3 tissues. The role of CD8 and NK cells in mediating the anti-tumor response was previously shown using depletion antibodies.[2]

Mice that became tumor-free from NKTR-214+anti-CTLA4 therapy and treatment naïve controls were rechallenged ~6 months later with either EMT6, CT26 or Sham buffer. No further treatment was given. Immune cells in spleen, lymph and blood were enumerated by flow cytometry, n=4/group. Graphs indicate proliferating Ki67+ total CD8 T cells (top) and effector memory CD8+ CD44hi CD67L-lo (bottom).

C. Transference of immune memory from tumor-free mice to recipient mice.

Durable anti-tumor immune memory demonstrated by adoptive spleen transfer from tumor-free mice to recipient mice. The recipients resist tumor growth without further treatment.

Mouse EMT6 breast tumors were implanted in recipient mice 1 day after receiving spleens from tumor-free mice or naïve mice; (****=p<0.0001 vs. normal control , two way ANOVA Tukey’s multiple comparison test, ns = non-significant)



• NKTR-214 mechanism of action delivers a controlled, sustained and biased signal to the IL-2 pathway, potentially mitigating systemic toxicities observed from bolus activation by IL-2 (aldesleukin)

• NKTR-214 provides marked efficacy in multiple tumor models, alone or in combination, using lower doses of reduced administration frequency

• Mobilization of T cells from the periphery into the tumor is an inherent property of NKTR-214

• NKTR-214 mechanism enables durable complete anti-tumor response with immune memory recall when combined with anti-CTLA4

• Treatment provides tumor-free mice that consistently eliminate new tumors even in the absence of further therapy • Mice becoming tumor-free from prior treatment reject new tumors by mounting a vigorous CD8+ effector memory response up to 6 months post-therapy

• Adoptive spleen transfer from tumor-free mice confers an anti-tumor response in recipient mice in the absence of further therapy

• NKTR-214 is being evaluated in an ongoing outpatient Phase 1/2 clinical trial for the treatment of solid tumors



[1] Boyman et al, Nature Reviews, 2012

[2] Charych et al, Clinical Cancer Research, 2016

[3] Spranger et al, J. Immunoth.. Cancer, 2014






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Signaling through the T Cell Receptor (TCR) Complex and the Co-stimulatory Receptor CD28

Curator: Larry H. Bernstein, MD, FCAP



New connections: T cell actin dynamics

Fluorescence microscopy is one of the most important tools in cell biology research because it provides spatial and temporal information to investigate regulatory systems inside cells. This technique can generate data in the form of signal intensities at thousands of positions resolved inside individual live cells. However, given extensive cell-to-cell variation, these data cannot be readily assembled into three- or four-dimensional maps of protein concentration that can be compared across different cells and conditions. We have developed a method to enable comparison of imaging data from many cells and applied it to investigate actin dynamics in T cell activation. Antigen recognition in T cells by the T cell receptor (TCR) is amplified by engagement of the costimulatory receptor CD28. We imaged actin and eight core actin regulators to generate over a thousand movies of T cells under conditions in which CD28 was either engaged or blocked in the context of a strong TCR signal. Our computational analysis showed that the primary effect of costimulation blockade was to decrease recruitment of the activator of actin nucleation WAVE2 (Wiskott-Aldrich syndrome protein family verprolin-homologous protein 2) and the actin-severing protein cofilin to F-actin. Reconstitution of WAVE2 and cofilin activity restored the defect in actin signaling dynamics caused by costimulation blockade. Thus, we have developed and validated an approach to quantify protein distributions in time and space for the analysis of complex regulatory systems.



Triple-Color FRET Analysis Reveals Conformational Changes in the WIP-WASp Actin-Regulating Complex



T cell activation by antigens involves the formation of a complex, highly dynamic, yet organized signaling complex at the site of the T cell receptors (TCRs). Srikanth et al. found that the lymphocyte-specific large guanosine triphosphatase of the Rab family CRACR2A-a associated with vesicles near the Golgi in unstimulated mouse and human CD4+ T cells. Upon TCR activation, these vesicles moved to the immunological synapse (the contact region between a T cell and an antigen-presenting cell). The guanine nucleotide exchange factor Vav1 at the TCR complex recruited CRACR2A-a to the complex. Without CRACR2A-a, T cell activation was compromised because of defective calcium and kinase signaling.

More than 60 members of the Rab family of guanosine triphosphatases (GTPases) exist in the human genome. Rab GTPases are small proteins that are primarily involved in the formation, trafficking, and fusion of vesicles. We showed that CRACR2A (Ca2+ release–activated Ca2+ channel regulator 2A) encodes a lymphocyte-specific large Rab GTPase that contains multiple functional domains, including EF-hand motifs, a proline-rich domain (PRD), and a Rab GTPase domain with an unconventional prenylation site. Through experiments involving gene silencing in cells and knockout mice, we demonstrated a role for CRACR2A in the activation of the Ca2+ and c-Jun N-terminal kinase signaling pathways in response to T cell receptor (TCR) stimulation. Vesicles containing this Rab GTPase translocated from near the Golgi to the immunological synapse formed between a T cell and a cognate antigen-presenting cell to activate these signaling pathways. The interaction between the PRD of CRACR2A and the guanidine nucleotide exchange factor Vav1 was required for the accumulation of these vesicles at the immunological synapse. Furthermore, we demonstrated that GTP binding and prenylation of CRACR2A were associated with its localization near the Golgi and its stability. Our findings reveal a previously uncharacterized function of a large Rab GTPase and vesicles near the Golgi in TCR signaling. Other GTPases with similar domain architectures may have similar functions in T cells.


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