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Posts Tagged ‘COVID-19’


Tiny biologic drug to fight COVID-19 show promise in animal models

Reporter : Irina Robu, PhD

A research team at University of Pittsburg School of Medicine identified an antibody component that is 10 times smaller than a full-sized antibody. Their research published in Cell, indicates that the drug, Ab8 based on it is effective in mice and hamsters. The research was started by screening a library of about 100 billion antibody fragments to identify candidates that bound tightly to the spike protein on SARS-CoV-2’s surface, which the virus uses to enter and infect human cells.

A typical antibody consists of two heavy chains and two light chains. The chosen molecule is the variable domain of the heavy chain of an immunoglobulin, which is a type of antibody. The heavy chain variable domain is essential for binding with an antigen. Ab8 was created by fusing the variable, heavy chain domain with part of the immunoglobulin tail region, giving it immune functions but doing so with a molecule that’s about half the size of a full immunoglobulin.

The smaller size of the antibody can improve the therapeutic efficacy for infectious diseases and can be delivered through inhalation. Their research showed that Ab8 completely neutralized SARS-CoV-2 in lab dishes. The drug developed showed that inhibited the virus in lung tissue in animal body even at the lowest dose 2 mg/kg as compared to untreated controls.

The research team is looking to determine the drug effect in hamsters, which were reported to have better clinical signatures of COVID-19. And the hamsters that got the drug display less severe pneumonia that did the control animals. Drugs with alternative administration routers could provide additions to the first wave of COVID-19 therapies and vaccines.

What is more important, Ab8 does not appear to bind to human cells which is a good sign that it won’t have negative side effects.

SOURCE

https://www.fiercebiotech.com/research/small-sized-biologic-against-covid-19-shows-promise-animal-models

 

 

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Llama inspired “AeroNabs” to strangle COVID-19 with an inhaler 

Reporter : Irina Robu, PhD

Llama and other camelids fight off pathogens like viruses with tiny antibodies called nanobodies. A USCF team used protein engineering to make a synthetic nanobody that prevents the spike protein on the surface of SARS-CoV-2 from binding to healthy cells and infecting them. The team indicates promising preclinical results for aerosol formulation and can be used as a self-administered form of protein against the virus.

According to the UCSF team, an aerosolized form of nanobody exhibit SARS-CoV-2 incapable of binding to the ACE2 receptor on healthy cells that line airways. The synthetic nanobody stays functional after it was freeze-dried, exposed to heat and aerosolized.

The researchers ongoing screening a library of synthetic nanobodies, ultimately landing on 21 that banned the spike-ACE2 interaction. The scientists decided that in order to be truly efficient, a nanobody based treatment with interact with all three of the receptor binding domains on the spike protein that attaches to ACE2.  Their solution was to engineer a molecular chain that connects three nanobodies together, which would ensure that when one of the nanobodies attached to RBD, the others would link to the two remaining RBD. This molecular chain resulted in a drug candidate proved to be 200,000 times more potent than a single antibody.

At the same time, ExeVir Bio is also developing an aerosolized COVID-19 treatment inspired by llamas and is currently trying to advance its candidate into clinical trials by the end of the year. Their main candidate, VHH-72Fc was considered to bind to an epitope that is found both in SARS-CoV-2 and SARS-CoV. Yet, the llama inspired treatments are still behind antibody efforts like that of Regeneron.

Even though, there are multiple vaccines in development, researchers at UCSF believe that AeroNabs can be used as a sort of personal protective equipment until vaccines become available. The same researchers are planning human trials and are in discussion with partners who can provide manufacturing and distribution backing.

SOURCE

https://www.fiercebiotech.com/research/ucsf-engineers-develop-llama-inspired-aeronabs-to-strangle-covid-19-inhaler

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FDA Authorizes Convalescent Plasma for COVID-19 Patients

Reporter: Irina Robu, PhD

The U.S. Food and Drug Administration authorized convalescent plasma therapy in August 2020 for people with coronavirus disease 2019. The convalescent plasma shows promising efficacy in hospitalized patients with COVID-19 and the benefits outweighs the risk  and FDA gave emergency use authorization. The approval is not  for any particular convalescent plasma product, but for preparation collected by FDA registered blood establishments from individuals whose plasma contains anti-SARS-CoV-2 antibodies, and who meet all donor eligibility requirements.

What exactly is convalescent plasma ? It is blood donated from patients who have recovered from COVID-19 has antibodies to the virus that causes it. The donated blood is processed by removing blood cells, leaving behind plasma and antibodies, which can be given to people with COVID-19 to boost their ability to fight the virus. According to FDA, COVID-19 covalescent plasma with high antibody titer can be effective in reducing mortality in hospitalized patients, but low antibody titer can be used based on health care provider discretion.  FDA also indicated that COVID-19 convalescent plasma may be effective in lessening the severity or shortening the length of COVID-19 illness in some hospitalized patients.

To confirm the results, the FDA recommended randomized trialsas COVID-19 convalescent plasma does not yet describe a new standard of care based on the current available evidence.

SOURCE

https://www.medpagetoday.com/infectiousdisease/covid19/88225?xid=NL_breakingnewsalert_2020-08-23

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Miniproteins against the COVID-19 Spike protein may be therapeutic

Reporter: Stephen J. Williams, PhD

Computer-designed proteins may protect against coronavirus

At a Glance

  • Researchers designed “miniproteins” that bound tightly to the SARS-CoV-2 spike protein and prevented the virus from infecting human cells in the lab.
  • More research is underway to test the most promising of the antiviral proteins.

 

 

 

 

 

 

 

An artist’s conception of computer-designed miniproteins (white) binding coronavirus spikes. UW Institute for Protein Design

The surface of SARS-CoV-2, the virus that causes COVID-19, is covered with spike proteins. These proteins latch onto human cells, allowing the virus to enter and infect them. The spike binds to ACE2 receptors on the cell surface. It then undergoes a structural change that allows it to fuse with the cell. Once inside, the virus can copy itself and produce more viruses.

Blocking entry of SARS-CoV-2 into human cells can prevent infection. Researchers are testing monoclonal antibody therapies that bind to the spike protein and neutralize the virus. But these antibodies, which are derived from immune system molecules, are large and not ideal for delivery through the nose. They’re also often not stable for long periods and usually require refrigeration.

Researchers led by Dr. David Baker of the University of Washington set out to design synthetic “miniproteins” that bind tightly to the coronavirus spike protein. Their study was funded in part by NIH’s National Institute of General Medical Sciences (NIGMS) and National Institute of Allergy and Infectious Diseases (NIAID). Findings appeared in Science on September 9, 2020.

The team used two strategies to create the antiviral miniproteins. First, they incorporated a segment of the ACE2 receptor into the small proteins. The researchers used a protein design tool they developed called Rosetta blueprint builder. This technology allowed them to custom build proteins and predict how they would bind to the receptor.

The second approach was to design miniproteins from scratch, which allowed for a greater range of possibilities. Using a large library of miniproteins, they identified designs that could potentially bind within a key part of the coronavirus spike called the receptor binding domain (RBD). In total, the team produced more than 100,000 miniproteins.

Next, the researchers tested how well the miniproteins bound to the RBD. The most promising candidates then underwent further testing and tweaking to improve binding.

Using cryo-electron microscopy, the team was able to build detailed pictures of how two of the miniproteins bound to the spike protein. The binding closely matched the predictions of the computational models.

Finally, the researchers tested whether three of the miniproteins could neutralize SARS-CoV-2. All protected lab-grown human cells from infection. Candidates LCB1 and LCB3 showed potent neutralizing ability. These were among the designs created from the miniprotein library. Tests suggested that these miniproteins may be more potent than the most effective antibody treatments reported to date.

“Although extensive clinical testing is still needed, we believe the best of these computer-generated antivirals are quite promising,” says Dr. Longxing Cao, the study’s first author. “They appear to block SARS-CoV-2 infection at least as well as monoclonal antibodies but are much easier to produce and far more stable, potentially eliminating the need for refrigeration.”

Notably, this study demonstrates the potential of computational models to quickly respond to future viral threats. With further development, researchers may be able to generate neutralizing designs within weeks of obtaining the genome of a new virus.

—by Erin Bryant

Source: https://www.nih.gov/news-events/nih-research-matters/computer-designed-proteins-may-protect-against-coronavirus

Original article in Science

De novo design of picomolar SARS-CoV-2 miniprotein inhibitors

 

  1. View ORCID ProfileLongxing Cao1,2
  2. Inna Goreshnik1,2
  3. View ORCID ProfileBrian Coventry1,2,3
  4. View ORCID ProfileJames Brett Case4
  5. View ORCID ProfileLauren Miller1,2
  6. Lisa Kozodoy1,2
  7. Rita E. Chen4,5
  8. View ORCID ProfileLauren Carter1,2
  9. View ORCID ProfileAlexandra C. Walls1
  10. Young-Jun Park1
  11. View ORCID ProfileEva-Maria Strauch6
  12. View ORCID ProfileLance Stewart1,2
  13. View ORCID ProfileMichael S. Diamond4,7
  14. View ORCID ProfileDavid Veesler1
  15. View ORCID ProfileDavid Baker1,2,8,*

See all authors and affiliations

Science  09 Sep 2020:
eabd9909
DOI: 10.1126/science.abd9909

Abstract

Targeting the interaction between the SARS-CoV-2 Spike protein and the human ACE2 receptor is a promising therapeutic strategy. We designed inhibitors using two de novo design approaches. Computer generated scaffolds were either built around an ACE2 helix that interacts with the Spike receptor binding domain (RBD), or docked against the RBD to identify new binding modes, and their amino acid sequences designed to optimize target binding, folding and stability. Ten designs bound the RBD with affinities ranging from 100pM to 10nM, and blocked ARS-CoV-2 infection of Vero E6 cells with IC 50 values between 24 pM and 35 nM; The most potent, with new binding modes, are 56 and 64 residue proteins (IC 50 ~ 0.16 ng/ml). Cryo-electron microscopy structures of these minibinders in complex with the SARS-CoV-2 spike ectodomain trimer with all three RBDs bound are nearly identical to the computational models. These hyperstable minibinders provide starting points for SARS-CoV-2 therapeutics.

 

RESEARCH ARTICLE

De novo design of picomolar SARS-CoV-2 miniprotein inhibitors

  1. View ORCID ProfileLongxing Cao1,2
  2. Inna Goreshnik1,2
  3. View ORCID ProfileBrian Coventry1,2,3
  4. View ORCID ProfileJames Brett Case4
  5. View ORCID ProfileLauren Miller1,2
  6. Lisa Kozodoy1,2
  7. Rita E. Chen4,5
  8. View ORCID ProfileLauren Carter1,2
  9. View ORCID ProfileAlexandra C. Walls1
  10. Young-Jun Park1
  11. View ORCID ProfileEva-Maria Strauch6
  12. View ORCID ProfileLance Stewart1,2
  13. View ORCID ProfileMichael S. Diamond4,7
  14. View ORCID ProfileDavid Veesler1
  15. View ORCID ProfileDavid Baker1,2,8,*

See all authors and affiliations

Science  09 Sep 2020:
eabd9909
DOI: 10.1126/science.abd9909

Abstract

Targeting the interaction between the SARS-CoV-2 Spike protein and the human ACE2 receptor is a promising therapeutic strategy. We designed inhibitors using two de novo design approaches. Computer generated scaffolds were either built around an ACE2 helix that interacts with the Spike receptor binding domain (RBD), or docked against the RBD to identify new binding modes, and their amino acid sequences designed to optimize target binding, folding and stability. Ten designs bound the RBD with affinities ranging from 100pM to 10nM, and blocked ARS-CoV-2 infection of Vero E6 cells with IC 50 values between 24 pM and 35 nM; The most potent, with new binding modes, are 56 and 64 residue proteins (IC 50 ~ 0.16 ng/ml). Cryo-electron microscopy structures of these minibinders in complex with the SARS-CoV-2 spike ectodomain trimer with all three RBDs bound are nearly identical to the computational models. These hyperstable minibinders provide starting points for SARS-CoV-2 therapeutics.

 

SARS-CoV-2 infection generally begins in the nasal cavity, with virus replicating there for several days before spreading to the lower respiratory tract (1). Delivery of a high concentration of a viral inhibitor into the nose and into the respiratory system generally might therefore provide prophylactic protection and/or therapeutic benefit for treatment of early infection, and could be particularly useful for healthcare workers and others coming into frequent contact with infected individuals. A number of monoclonal antibodies are in development as systemic treatments for COVID-19 (26), but these proteins are not ideal for intranasal delivery as antibodies are large and often not extremely stable molecules and the density of binding sites is low (two per 150 KDa. antibody); antibody-dependent disease enhancement (79) is also a potential issue. High-affinity Spike protein binders that block the interaction with the human cellular receptor angiotensin-converting enzyme 2 (ACE2) (10) with enhanced stability and smaller sizes to maximize the density of inhibitory domains could have advantages over antibodies for direct delivery into the respiratory system through intranasal administration, nebulization or dry powder aerosol. We found previously that intranasal delivery of small proteins designed to bind tightly to the influenza hemagglutinin can provide both prophylactic and therapeutic protection in rodent models of lethal influenza infection (11).

Design strategy

We set out to design high-affinity protein minibinders to the SARS-CoV-2 Spike RBD that compete with ACE2 binding. We explored two strategies: first we incorporated the alpha-helix from ACE2 which makes the majority of the interactions with the RBD into small designed proteins that make additional interactions with the RBD to attain higher affinity (Fig. 1A). Second, we designed binders completely from scratch without relying on known RBD-binding interactions (Fig. 1B). An advantage of the second approach is that the range of possibilities for design is much larger, and so potentially a greater diversity of high-affinity binding modes can be identified. For the first approach, we used the Rosetta blueprint builder to generate miniproteins which incorporate the ACE2 helix (human ACE2 residues 23 to 46). For the second approach, we used RIF docking (12) and design using large miniprotein libraries (11) to generate binders to distinct regions of the RBD surface surrounding the ACE2 binding site (Fig. 1 and fig. S1).

 

 

 

 

 

 

 

 

 

 

 

Download high-res image

Fig. 1 Overview of the computational design approaches.

(A) Design of helical proteins incorporating ACE2 helix. (B) Large scale de novo design of small helical scaffolds (top) followed by rotamer interaction field (RIF) docking to identify shape and chemically complementary binding modes.

For full article please  go to Science at https://science.sciencemag.org/content/early/2020/09/08/science.abd9909

 

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Black doctors’ group creates panel to vet Covid-19 vaccines

Reporter : Irina Robu, PhD

A group of black physicians have been working on creating their own expert task force to vet regulators’ decisions about COVID-19 drugs and vaccines, due to the fact that the trust in federal agencies has weakened over the last few months.

According to the president of NMA, Leon McDougle, the new task force will address the suspicion around COVID-19 vaccines. The fear is that the vaccines might not be safe or properly tested before they are approved which makes it the reason some patients of color are wary about taking part in the clinical trials.  The task force will evaluate how well the clinical trials participants characterize demographic breakdown of American population and the fairness of the federal plans to distribute a vaccine to Black, Latino and Native American communities.

The leaders of the black community task force are still figuring out how it will work and what happens if FDA authorizes the use of product without releasing the full data to support it. As past president of the NMA, Dr. Rodney Hood knows that the organization has in its ranks the kind of expertise that could analyze clinical trial data along with expertise in epidemiology and infectious disease.

The black community task force hopes that they are able to tell their patients about the scientific findings regarding COVID-19 vaccine with full transparency and disclosure.

SOURCE

https://www.statnews.com/2020/09/21/black-doctors-group-creates-panel-to-vet-covid19-vaccines/?utm_source=STAT+NewslettersTop of Form

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Toaster Sized Machine Detects COVID-19

Reporter: Irina Robu, PhD

DnaNudge, a small UK-based DNA testing company designed a toaster sized machine that can detect COVID-19 in 90 min without lab analysis. The machine invented by Christofer Toumazou, professor at Imperial College was designed to aid people tailor their diet based on heredity, but changed the design due to the pandemic. The machine needs a nose swab or some saliva to detect traces of coronavirus. It can even spot other diseases such as the flu and a common virus infection called Respiratory Syncytial Virus (RSV). It will also notify the operator if a proper sample has been taken or if a test needs to be retaken.

Currently, the UK National Health Service ordered 5,000 of the machines, as well as cartridges to start testing coronavirus patients, as part of a $211 million contract. They are hoping that the machine designed by DNANudge states that can prove helpful in triaging potential COVID patients.

SOURCE

 https://futurism.com/neoscope/machine-covid-90-minutes?mc_eid=8eae667eea

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Is SARS-COV2 Hijacking the Complement and Coagulation Systems?

Reporter: Stephen J. Williams, PhD

In a recent Nature Medicine paper “Immune complement and coagulation dysfunction in adverse outcomes of SARS-CoV-2 infection” Ramlall et al. demonstrate, in a retrospective study, that a significant number of patients presenting SARS-CoV2 complications had prior incidences of macular degeneration and coagulation disorders and these previous indications are risk factors for COVID-related complications.

 

Abstract

Understanding the pathophysiology of SARS-CoV-2 infection is critical for therapeutic and public health strategies. Viral–host interactions can guide discovery of disease regulators, and protein structure function analysis points to several immune pathways, including complement and coagulation, as targets of coronaviruses. To determine whether conditions associated with dysregulated complement or coagulation systems impact disease, we performed a retrospective observational study and found that history of macular degeneration (a proxy for complement-activation disorders) and history of coagulation disorders (thrombocytopenia, thrombosis and hemorrhage) are risk factors for SARS-CoV-2-associated morbidity and mortality—effects that are independent of age, sex or history of smoking. Transcriptional profiling of nasopharyngeal swabs demonstrated that in addition to type-I interferon and interleukin-6-dependent inflammatory responses, infection results in robust engagement of the complement and coagulation pathways. Finally, in a candidate-driven genetic association study of severe SARS-CoV-2 disease, we identified putative complement and coagulation-associated loci including missense, eQTL and sQTL variants of critical complement and coagulation regulators. In addition to providing evidence that complement function modulates SARS-CoV-2 infection outcome, the data point to putative transcriptional genetic markers of susceptibility. The results highlight the value of using a multimodal analytical approach to reveal determinants and predictors of immunity, susceptibility and clinical outcome associated with infection.

Introduction

As part of a separate study, the authors mapped over 140 cellular proteins that are structurally mimicked by coronaviruses (CoVs) and identified complement and coagulation pathways as targets of this strategy across all CoV strains4. The complement system is a critical defense against pathogens, including viruses5 and when dysregulated (by germline variants or acquired through age-related effects or excessive tissue damage) can contribute to pathologies mediated by inflammation5,6,7.

“So, virally encoded structural mimics of complement and coagulation factors may contribute to CoV-associated immune-mediated pathology and indicate sensitivities in antiviral defenses.”

 

Methods and Results

  • Between 1 February 2020 and 25 April 2020, 11,116 patients presented to New York-Presbyterian/Columbia University Irving Medical Center with suspected SARS-CoV-2 infection, of which 6,398 tested positive
  • Electronic health records (EHRs) were used to define sex, age and smoking history status as well as histories of macular degeneration, coagulatory disorders (thrombocytopenia, thrombosis and hemorrhage), hypertension, type 2 diabetes (T2D), coronary artery disease (CAD) and obesity (see Methods). A Python algorithm was used to analyze all confounders.
  • identified 88 patients with history of macular degeneration, 4 with complement deficiency disorders and 1,179 with coagulatory disorders).
  • observed a 35% mortality rate among patients that were put on mechanical ventilation and that 31% of deceased patients had been on mechanical respiration.
  • patients with AMD (a proxy for complement activation disorders) and coagulation disorders (thrombocytopenia, thrombosis and hemorrhage) were at significantly increased risk of adverse clinical outcomes (including mechanical respiration and death) following SARS-CoV-2 infection
  • 650 NP swabs from control and SARS-CoV-2-infected patients who presented to Weill-Cornell Medical Center were evaluated by RNA-Seq. Gene set enrichment analysis (GSEA) of Hallmark gene sets found that SARS-CoV-2 infection (as defined by presence of SARS-CoV-2 RNA and stratified into ‘positive’, ‘low’, ‘medium’ or ‘high’ based on viral load; induces genes related to pathways with known immune modulatory functions (Fig. 2a). Moreover, among the most enriched gene sets, SARS-CoV-2 infection induces robust activation of the complement cascade (false discovery rate (FDR) P < 0.001), with increasing enrichment and significance with viral load (FDR P < 0.0001).
  • KEGG Pathway Analysis revealed KEGG_Complement_and_Coagulation_Cascades’, ‘GO_Coagulation’ and ‘Reactome_initial_triggering_of_complement’ to be significantly enriched in expression profiles of SARS-CoV-2-infected samples
  • conducted a candidate-driven study to evaluate whether genetic variation within a 60-Kb window around 102 genes with known roles in regulating complement or coagulation cascades (2,888 genetic variants fulfill this criteria of the 805,426 profiled in the UK Biobank) is associated with poor SARS-CoV-2 clinical outcome
  • identified 11 loci representing seven genes with study-wide significance. A variant of coagulation factor III (F3), variant rs72729504, was found to be associated with increased risk of adverse clinical outcome associated with SARS-CoV-2 infection. The analysis also identified that four variants previously reported to be associated with AMD (rs45574833, rs61821114, rs61821041 and rs12064775)15predispose carriers to hospitalization following SARS-CoV-2 infection

As authors state:

“Among the implications, the data warrant heightened public health awareness for the most vulnerable individuals and further investigation into an existing menu of complement and coagulation targeting therapies that were recently shown to be beneficial in a small cohort of patients with SARS-CoV-2 infection.” 26,27.

 

References

Ramlall, V., Thangaraj, P.M., Meydan, C. et al. Immune complement and coagulation dysfunction in adverse outcomes of SARS-CoV-2 infection. Nat Med (2020). https://doi.org/10.1038/s41591-020-1021-2

 

4.

Lasso, G., Honig, B. & Shapira, S. D. A sweep of earth’s virome reveals host-guided viral protein structural mimicry; with implications for human disease. Preprint at bioRxiv https://doi.org/10.1101/2020.06.18.159467 (2020).

 

SUMMARY

Viruses deploy an array of genetically encoded strategies to coopt host machinery and support viral replicative cycles. Molecular mimicry, manifested by structural similarity between viral and endogenous host proteins, allow viruses to harness or disrupt cellular functions including nucleic acid metabolism and modulation of immune responses. Here, we use protein structure similarity to scan for virally encoded structure mimics across thousands of catalogued viruses and hosts spanning broad ecological niches and taxonomic range, including bacteria, plants and fungi, invertebrates and vertebrates. Our survey identified over 6,000,000 instances of structural mimicry, the vast majority of which (>70%) cannot be discerned through protein sequence. The results point to molecular mimicry as a pervasive strategy employed by viruses and indicate that the protein structure space used by a given virus is dictated by the host proteome. Interrogation of proteins mimicked by human-infecting viruses points to broad diversification of cellular pathways targeted via structural mimicry, identifies biological processes that may underly autoimmune disorders, and reveals virally encoded mimics that may be leveraged to engineer synthetic metabolic circuits or may serve as targets for therapeutics. Moreover, the manner and degree to which viruses exploit molecular mimicry varies by genome size and nucleic acid type, with ssRNA viruses circumventing limitations of their small genomes by mimicking human proteins to a greater extent than their large dsDNA counterparts. Finally, we identified over 140 cellular proteins that are mimicked by CoV, providing clues about cellular processes driving the pathogenesis of the ongoing COVID-19 pandemic.

 

26.

Risitano, A. M. Complement as a target in COVID-19?. Nat. Rev. Immunol. 20, 343–344 (2020).

 

27.

Mastaglio, S. et al. The first case of COVID-19 treated with the complement C3 inhibitor AMY-101. Clin. Immunol. 215, 108450 (2020).

 

28.

Polubriaginof, F. C. G. et al. Challenges with quality of race and ethnicity data in observational databases. J. Am. Med. Inf. Assoc. 26, 730–736 (2019).

 

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Novel SARS-CoV-2 sybodies

Reporter: Irina Robu, PhD

Absolute Antibody Ltd., a leader of the market in recombinant antibody products announced a partnership with University of Zurich to offer synthetic nanobodies against the receptor binding domain (RBD) of SARS-CoV-2. Under the partnership, the original nanobodies and recently engineered formats are now accessible to the global research community for use as serological controls and in COVID-19 therapeutic development. The synthetic nanobodies hold a particular potential for the development of inhalable drugs, which could suggest a convenient treatment option for the COVID-19 pandemic.

The laboratory of Markus Seeger at University of Zurich designs a rapid in vitro selection platform to generate synthetic nanobodies, sybodies, against the receptor binding domain (RBD) of SARS-CoV-2. Within a two-week timeframe, the lab had recognized more than 60 unique anti-RBD sybodies from combinatorial display libraries. The sybodies are “designed to mimic the natural shape diversity of camelid nanobodies, consequently allowing for an optimal surface complementarity to the limited hydrophilic epitopes on membrane proteins. Due to their high thermal stabilities and low production costs, sybodies demonstrate a promise for diagnostic and therapeutic applications.

Sybodies are perfectly suited to trap intrinsically flexible membrane proteins and thereby facilitate structure determination by X-ray crystallography and cryo-EM. Additional research indicate that six of the sybodies bound SARS-CoV-2 spike protein with very high affinity, while five of those also inhibited ACE2, the host cell receptor to which SARS-CoV-2 binds to initiate the COVID-19 infection. Furthermore, two of the sybodies can at the same time bind the RBD, which could permit the construction of a polyvalent antiviral drug. The SARS-CoV-2 sybodies are therefore valuable tools for coronavirus research, diagnostics and therapeutic development.

Moreover, Absolute Antibody has used antibody engineering to fuse the nanobodies to Fc domains in different species, isotypes and subtypes. Absolute Antibody also offers supporting coronavirus research such as the production of gram quantities of human antibodies sequenced from recovering COVID-19 patients.

SOURCE

https://www.biocompare.com/Life-Science-News/562900-SARS-CoV-2-COVID-19-Research-News-Latest-Updates

 

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Three Stages to COVID-19 Brain Damage

Reporter: Irina Robu, PhD

According to a review published by Majid Fotuhi, PhD in the Journal of Alzheimer’s Disease, the impact of COVID-19 on the nervous system can be classified in three stages. In stage 1, viral damage is limited to the epithelial cells of the nose and mouth; stage 2, blood clots that form in the lungs can travel to the brain and in stage 3, the virus crosses the blood brain barrier and invades the brain.

Dr. Fotuhi recognized that patients with COVID-19 should have a neurological evaluation and an MRI before leaving the hospital, to distinguish if there are any anomalies. It has become increasingly obvious that SARS-CoV-2 can cause neurologic manifestations, including anosmia, seizures, stroke, confusion, encephalopathy, and total paralysis, the authors write. As stated by authors of the review, the SARS-CoV-2 binds to angiotensin-converting enzyme 2 (ACE2) that facilitates the conversion of angiotensin II to angiotensin. Subsequently ACE2 binds to respiratory epithelial cells, and then to epithelial cells in blood vessels, SARS-CoV-2 triggers the formation of a “cytokine storm.” The cytokines, increase vascular permeability, edema and widespread inflammation which can cause small or large blood clots that affect multiple organs.

They concluded, that If SARS-CoV-2 crosses the blood–brain barrier, directly entering the brain, it can contribute to demyelination or neurodegeneration. Scientists have limited information published about it, so doctors/scientists are uncertain why a virus this small can cause so many neurological things.

SOURCE

https://www.medscape.com/viewarticle/933131

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Does CSF Antibody Testing Confirm Coronavirus in the Brain?

Reporter: Irina Robu, PhD

It is still uncertain how COVID-19 invades the brain, but testing for antibodies in the cerebrospinal fluid may give some indication.  COVID-19 is typic Is characterized by respiratory illness and viral pneumonia with fever, cough, shortness of breath, and in severe cases, progression to acute respiratory distress syndrome. Recently, there have been a few investigations on what neurological complications can COVID-19 produce.

A case series of three patients attending an inner-city US hospital who had severe, laboratory-confirmed COVID-19 and encephalitis indicated that while only one had abnormal white blood cells or protein present in cerebral spinal fluid, all had evidence of immunoglobulin (IgM) antibodies. The cases include a 31-year-old woman with sickle cell disease who had a recent pulmonary embolus, a 34-year-old woman with sign of fever, shortness of breath and hypertension and a 64-year-old with hypertension. Dr. Benameur, from Emory University assessed cerebrospinal fluid inflammatory proteins and completed testing for SARS-CoV-2 using reverse transcription polymerase chain reaction (PCR).

The results show that two of the patients had normal white blood cell counts and protein levels. Yet, according to Dr. Benameur, even though the PCR in cerebral spinal fluid is negative, it doesn’t mean that the virus didn’t make it into the brain. The PCR test is good for some viruses, but it is not as reliable for this new coronavirus. Even though, all patients had encephalitis, the female patients also developed encephalomyelitis as indicated by inflammation in her brain and spinal cord.

Altogether, patients had symptoms affecting cortical and brainstem function at the peak of neurologic illness.

SOURCE

https://www.medscape.com/viewarticle/931964?src=mkm_covid_update_200608_mscpedit

 

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