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Archive for the ‘Coronavirus Gene Expression’ Category


Cryo-EM disclosed how the D614G mutation changes SARS-CoV-2 spike protein structure.

Reporter: Dr. Premalata Pati, Ph.D., Postdoc

SARS-CoV-2, the virus that causes COVID-19, has had a major impact on human health globally; infecting a massive quantity of people [ADD HERE the Global Number from John Hopkins University https://coronavirus.jhu.edu/data]; causing severe disease and associated long-term health sequelae; resulting in death and excess mortality, especially among older and prone populations; interrupting altering routine healthcare services; disruptions to travel, trade, education, and many other societal functions; and more broadly having a negative impact on peoples physical and mental health.

It’s need of the hour to answer the questions like what allows the variants of SARS-CoV-2 first detected in the UK, South Africa, and Brazil to spread so quickly? How can current COVID-19 vaccines better protect against them?

Scientists from the Harvard Medical School and the Boston Children’s Hospital help answer these urgent questions. The team reports its findings in the journal “Science a paper entitled Structural impact on SARS-CoV-2 spike protein by D614G substitution. The mutation rate of the SARS-CoV-2 virus has rapidly evolved over the past few months, especially at the Spike (S) protein region of the virus, where the maximum number of mutations have been observed by the virologists.

Bing Chen, HMS professor of pediatrics at Boston Children’s, and colleagues analyzed the changes in the structure of the spike proteins with the genetic change by D614G mutation by all three variants. Hence they assessed the structure of the coronavirus spike protein down to the atomic level and revealed the reason for the quick spreading of these variants.


This model shows the structure of the spike protein in its closed configuration, in its original D614 form (left) and its mutant form (G614). In the mutant spike protein, the 630 loop (in red) stabilizes the spike, preventing it from flipping open prematurely and rendering SARS-CoV-2 more infectious.

Fig. 2 Cryo-EM structures of the full-length SARS-CoV-2 S protein carrying G614.

(A) Three structures of the G614 S trimer, representing a closed, three RBD-down conformation, an RBD-intermediate conformation and a one RBD-up conformation, were modeled based on corresponding cryo-EM density maps at 3.1-3.5Å resolution. Three protomers (a, b, c) are colored in red, blue and green, respectively. RBD locations are indicated. (B) Top views of superposition of three structures of the G614 S in (A) in ribbon representation with the structure of the prefusion trimer of the D614 S (PDB ID: 6XR8), shown in yellow. NTD and RBD of each protomer are indicated. Side views of the superposition are shown in fig. S8.

IMAGE SOURCE: Bing Chen, Ph.D., Boston Children’s Hospital, https://science.sciencemag.org/content/early/2021/03/16/science.abf2303

The work

The mutant spikes were imaged by Cryo-Electron microscopy (cryo-EM), which has resolution down to the atomic level. They found that the D614G mutation (substitution of in a single amino acid “letter” in the genetic code for the spike protein) makes the spike more stable as compared with the original SARS-CoV-2 virus. As a result, more functional spikes are available to bind to our cells’ ACE2 receptors, making the virus more contagious.


Cryo-EM revealed how the D614G mutation changes SARS-CoV-2 spike protein structure.

IMAGE SOURCE:  Zhang J, et al., Science

Say the original virus has 100 spikes,” Chen explained. “Because of the shape instability, you may have just 50 percent of them functional. In the G614 variants, you may have 90 percent that is functional. So even though they don’t bind as well, the chances are greater and you will have an infection

Forthcoming directions by Bing Chen and Team

The findings suggest the current approved COVID-19 vaccines and any vaccines in the works should include the genetic code for this mutation. Chen has quoted:

Since most of the vaccines so far—including the Moderna, Pfizer–BioNTech, Johnson & Johnson, and AstraZeneca vaccines are based on the original spike protein, adding the D614G mutation could make the vaccines better able to elicit protective neutralizing antibodies against the viral variants

Chen proposes that redesigned vaccines incorporate the code for this mutant spike protein. He believes the more stable spike shape should make any vaccine based on the spike more likely to elicit protective antibodies. Chen also has his sights set on therapeutics. He and his colleagues are further applying structural biology to better understand how SARS-CoV-2 binds to the ACE2 receptor. That could point the way to drugs that would block the virus from gaining entry to our cells.

In January, the team showed that a structurally engineered “decoy” ACE2 protein binds to SARS-CoV-2 200 times more strongly than the body’s own ACE2. The decoy potently inhibited the virus in cell culture, suggesting it could be an anti-COVID-19 treatment. Chen is now working to advance this research into animal models.

Main Source:

Abstract

Substitution for aspartic acid by glycine at position 614 in the spike (S) protein of severe acute respiratory syndrome coronavirus 2 appears to facilitate rapid viral spread. The G614 strain and its recent variants are now the dominant circulating forms. We report here cryo-EM structures of a full-length G614 S trimer, which adopts three distinct prefusion conformations differing primarily by the position of one receptor-binding domain. A loop disordered in the D614 S trimer wedges between domains within a protomer in the G614 spike. This added interaction appears to prevent premature dissociation of the G614 trimer, effectively increasing the number of functional spikes and enhancing infectivity, and to modulate structural rearrangements for membrane fusion. These findings extend our understanding of viral entry and suggest an improved immunogen for vaccine development.

https://science.sciencemag.org/content/early/2021/03/16/science.abf2303?rss=1

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COVID-19-vaccine rollout risks and challenges

Reporter : Irina Robu, PhD

https://pharmaceuticalintelligence.com/2021/02/17/covid-19-vaccine-rollout-risks-and-challenges/

COVID-19 Sequel: Neurological Impact of Social isolation been linked to poorer physical and mental health

Reporter: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2021/03/30/covid-19-sequel-neurological-impact-of-social-isolation-been-linked-to-poorer-physical-and-mental-health/

Comparing COVID-19 Vaccine Schedule Combinations, or “Com-COV” – First-of-its-Kind Study will explore the Impact of using eight different Combinations of Doses and Dosing Intervals for Different COVID-19 Vaccines

Reporter: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2021/02/08/comparing-covid-19-vaccine-schedule-combinations-or-com-cov-first-of-its-kind-study-will-explore-the-impact-of-using-eight-different-combinations-of-doses-and-dosing-intervals-for-diffe/

COVID-19 T-cell immune response map, immunoSEQ T-MAP COVID for research of T-cell response to SARS-CoV-2 infection

Reporter: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2020/11/20/covid-19-t-cell-immune-response-map-immunoseq-t-map-covid-for-research-of-t-cell-response-to-sars-cov-2-infection/

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

Reporter : Irina Robu, PhD

https://pharmaceuticalintelligence.com/2020/10/11/tiny-biologic-drug-to-fight-covid-19-show-promise-in-animal-models/

Miniproteins against the COVID-19 Spike protein may be therapeutic

Reporter: Stephen J. Williams, PhD

https://pharmaceuticalintelligence.com/2020/09/30/miniproteins-against-the-covid-19-spike-protein-may-be-therapeutic/

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T cells recognize recent SARS-CoV-2 variants

Reporter: Aviva Lev-Ari, PhD, RN

CD8+ T cell responses in COVID-19 convalescent individuals target conserved epitopes from multiple prominent SARS-CoV-2 circulating variants 

Andrew D ReddAlessandra NardinHassen KaredEvan M BlochAndrew PekoszOliver LaeyendeckerBrian AbelMichael FehlingsThomas C QuinnAaron A R TobianOpen Forum Infectious Diseases, ofab143, https://doi.org/10.1093/ofid/ofab143Published: 30 March 2021 Article history

Abstract

This study examined whether CD8+ T-cell responses from COVID-19 convalescent individuals (n=30) potentially maintain recognition of the major SARS-CoV-2 variants (n=45 mutations assessed). Only one mutation found in B.1.351-Spike overlapped with a previously identified epitope (1/52), suggesting that virtually all anti-SARS-CoV-2 CD8+ T-cell responses should recognize these newly described variants.

Key words:

CD8+ T cellSARS-CoV-2COVID-19Convalescent patients

Topic: 

SOURCE

https://academic.oup.com/ofid/advance-article/doi/10.1093/ofid/ofab143/6189113

Original paper:

Andrew D Redd, Alessandra Nardin, Hassen Kared, Evan M Bloch, Andrew Pekosz, Oliver Laeyendecker, Brian Abel, Michael Fehlings, Thomas C Quinn, Aaron A R Tobian, CD8+ T cell responses in COVID-19 convalescent individuals target conserved epitopes from multiple prominent SARS-CoV-2 circulating variants, Open Forum Infectious Diseases, 2021;, ofab143, https://doi.org/10.1093/ofid/ofab143

Tuesday, March 30, 2021

T cells recognize recent SARS-CoV-2 variants

Healthy Human T CellScanning electron micrograph of a human T lymphocyte (also called a T cell) from the immune system of a healthy donor. NIAID

What

When variants of SARS-CoV-2 (the virus that causes COVID-19) emerged in late 2020, concern arose that they might elude protective immune responses generated by prior infection or vaccination, potentially making re-infection more likely or vaccination less effective. To investigate this possibility, researchers from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, and colleagues analyzed blood cell samples from 30 people who had contracted and recovered from COVID-19 prior to the emergence of virus variants. They found that one key player in the immune response to SARS-CoV-2—the CD8+ T cell—remained active against the virus.

The research team was led by NIAID’s Andrew Redd, Ph.D., and included scientists from Johns Hopkins University School of Medicine, Johns Hopkins Bloomberg School of Public Health and the Immunomics-focused company, ImmunoScape.

The investigators asked whether CD8+ T cells in the blood of recovered COVID-19 patients, infected with the initial virus, could still recognize three SARS-CoV-2 variants: B.1.1.7, which was first detected in the United Kingdom; B.1.351, originally found in the Republic of South Africa; and B.1.1.248, first seen in Brazil. Each variant has mutations throughout the virus, and, in particular, in the region of the virus’ spike protein that it uses to attach to and enter cells. Mutations in this spike protein region could make it less recognizable to T cells and neutralizing antibodies, which are made by the immune system’s B cells following infection or vaccination.

Although details about the exact levels and composition of antibody and T-cell responses needed to achieve immunity to SARS-CoV-2 are still unknown, scientists assume that strong and broad responses from both antibodies and T cells are required to mount an effective immune response.  CD8+ T cells limit infection by recognizing parts of the virus protein presented on the surface of infected cells and killing those cells.

In their study of recovered COVID-19 patients, the researchers determined that SARS-CoV-2-specific CD8+ T-cell responses remained largely intact and could recognize virtually all mutations in the variants studied. While larger studies are needed, the researchers note that their findings suggest that the T cell response in convalescent individuals, and most likely in vaccinees, are largely not affected by the mutations found in these three variants, and should offer protection against emerging variants.   

Optimal immunity to SARS-Cov-2 likely requires strong multivalent T-cell responses in addition to neutralizing antibodies and other responses to protect against current SARS-CoV-2 strains and emerging variants, the authors indicate. They stress the importance of monitoring the breadth, magnitude and durability of the anti-SARS-CoV-2 T-cell responses in recovered and vaccinated individuals as part of any assessment to determine if booster vaccinations are needed. 

SOURCE

https://www.nih.gov/news-events/news-releases/t-cells-recognize-recent-sars-cov-2-variants

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Glycosylation and its Role in SARS-CoV-2 Viral Pathogenesis

Author: Meg Baker, PhD

 

N-Glycosylation and COVID19

Glycobiology

N-linked glycosylation (NLG) is a complex biosynthetic process that regulates proper folding of proteins through and intracellular transport of proteins to the secretory pathway. This co- and post-translational modification occurs by a series of enzymatic reactions, which results in the transfer of a core glycan from the lipid carrier to a protein substrate and the possibility for further remodeling of the glycan. The enzymes are located in the cytosolic and the luminal side of the ER membrane. The study of NLG and related effects of glycans is called glycobiology.

NLG takes place at sites specified in the protein sequence itself. N-linked oligosaccharides are attached via a GlcNAc linked to the side chain nitrogen of Asn found in the consensus sequence NXT/S (X ≠ P) known as the ‘glycosylation sequon’. Formation of a precursor branched carbohydrate chain, the lipid-linked oligosaccharide (LLO) structure, takes place in the endoplasmic reticulum. The LLO consists of a Glc3Man9GlcNAc2 molecule (three glucose, nine mannose, and two N-acetylglucosamine sugars) linked to a dolichol pyrophosphate. The enzyme oligosaccharyltransferase then moves it to an Asn in the polypeptide.

The removal of the three glucose sugars from the new N-linked glycan signals that the structure is ready for transport to the Golgi where mannose is removed yielding a carbohydrate chain containing five–nine mannose sugars. Further removal of mannose residues can lead to the core structure containing three mannose and two N-acetylglucosamine residues, which may then be elongated with a variety of different monosaccharides including galactose, N-acetylglucosamine (aka NAG or GlcNac), N-acetylgalactosamine, fucose, and sialic acid, many of which can also exist in sulfated form.

The enzymes involved in this essential process are evolutionarily conserved. However, the genes and their specific functions, have evolved uniquely for each selected organism. Therefore, each organism and each individual cell, depending on genetic background and influenced by nutritional and such things as disease status, will decorate secreted proteins in a unique manner.

The advent of biologic medicines (protein based therapeutics) presents the challenge of making sure that the primary protein sequence is specified but also that the manufacture of the protein – typically in a eukaryotic cell host capable of glycosylation – will take place with some degree of reproducibility. The large number of monoclonal antibody therapeutics absolutely require glycosylation for proper structural integrity but are generally made in rodent or other nonhuman cells. Thus, the term “biosimilar” rather than generic is the term being used to connote the variation which will necessarily result due to different manufacturing process even of the same genetic sequence.

 

Viral Glycoproteins

It should be obvious that the viral genome is not large enough to encompass the collection of enzymes required for glycosylation of any type and viral glycoproteins are formed by the host cell in which the virus is replicating. The study of the impact of glycan content and composition on viral infectivity and, more importantly, vaccine development is a subject which has been late to be addressed largely due to the technical difficulty and lack of methods for analyzing protein glycan composition. However, progress is being made. Raska et al. (J Biol Chem 2010 Jul 2; 285(27): 20860–20869. Glycosylation Patterns of HIV-1 gp120 Depend on the Type of Expressing Cells and Affect Antibody Recognition)  was able to perform such an analysis on the HIV-1 virus albeit almost 30 years after its emergence in human populations. The findings of this study may explain, in part, the difficulty in developing a vaccine against HIV.

 

SARS-CoV-2 spike protein (P0DTC2 uniprot.org) – as so popularly depicted – is a trimer poking out of the lipid coat that protects it’s genome. The spike protein, like gp120 in HIV, is the point of contact with the human cell ACE2 receptor it uses to gain entry. The spike protein contains two functional external subunits, designated S1 and S2. S1 separated by a furin cleavage site from S2, forms the apex of the trimeric spike structure, is responsible for attachment to the ACE2 receptor. S2 is responsible for fusion to the cell membrane. (PDB: 6VSB shows a 3D image of the protein structure, including glycan positions). There are 22 glycans per polypeptide or 66 per spike trimer protein (Watanabe et al. 2021 Site-specific glycan analysis of the SARS-CoV-2 spike. Science 17 Jul 2020:Vol. 369, Issue 6501, pp. 330-333 ).

Although shielding of receptor binding sites by glycans is a common feature of viral glycoproteins, Watanabe (ibid) note the low mutation rate of SARS-CoV-2 and that as yet, there have been no observed mutations to N-linked glycosylation sites.

The development of a vaccine or individual antibodies or antibody cocktails with neutralizing (viral entry blocking or virocidal activity) is also influenced by the presence or absence of glycans and how well they target the natural conformation of the spike protein. Papageorgiou et al. The SARS-CoV-2 Spike Glycoprotein as a Drug and Vaccine Target: Structural Insights into Its Complexes with ACE2 and Antibodies. Cells 2020 Oct 22;9(11):2343. doi: 10.3390/cells9112343. SARS-CoV-2 Spike – Stanford Coronavirus Antiviral Research Database It should be noted that the mRNA vaccines (or other nucleic acid formats) may obviate these analysis because the immune response is to a spike protein made and glycosylated in the human host’s own body and therefore will be customized to each individual in some sense.

Glycans may themselves represent drug targets. Casolino et al. suggest an essential structural role of N-glycans at sites N165 and N234 in modulating the conformational dynamics of the spike’s receptor binding domain (RBD), which is responsible for ACE2 recognition (Casolino et al. 2020. Beyond Shielding: The Roles of Glycans in the SARS-CoV-2 Spike Protein ACS Cent Sci. 2020 Oct 28; 6(10): 1722–1734),

 

COVID19 Variants

SARS-CoV-2 lineage B.1.1.7 likely arose in the United Kingdom in September 2019 and is characterized by 17 mutations, including 8 in the spike protein (Rambaut et al., 2020). Other lineages, including B.1.351, initially detected in South Africa (Tegally et al., 2020), and most recently lineage P.1, first documented in the Amazonia region of Brazil (Faria et al., 2020), carry additional mutations. All three lineages are characterised by a N501Y (Asn to Tyr) mutation in the spike protein, while both B.1.351 and P.1 also carry the spike mutation E484K. In addition, both B.1.1.7 and B.1.351, but not P.1, have acquired short sequence deletions in the spike protein. N501Y is in the receptor-binding domain (RBD) but is not a glycosylation site.

Reference

See the CDC Emerging SARS-CoV-2 Variants | CDC

 

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Need for Global Response to SARS-CoV-2 Viral Variants

Reporter: Aviva Lev-Ari, PhD, RN

NIH experts discuss SARS-CoV-2 viral variants

Editorial emphasizes need for global response.

 

The rise of several significant variants of SARS-CoV-2, the virus that causes COVID-19, has attracted the attention of health and science experts worldwide. In an editorial published today in JAMA: The Journal of the American Medical Association, experts from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, outline how these variants have arisen, concerns about whether vaccines currently authorized for use will continue to protect against new variants, and the need for a global approach to fighting SARS-CoV-2 as it spreads and acquires additional mutations.

The article was written by NIAID Director Anthony S. Fauci, M.D.; John R. Mascola, M.D., director of NIAID’s Vaccine Research Center (VRC); and Barney S. Graham, M.D., Ph.D., deputy director of NIAID’s VRC.

The authors note that the overlapping discovery of several SARS-CoV-2 variants has led to confusing terms used to name them. The appearance of SARS-CoV-2 variants is so recent that the World Health Organization and other groups are still developing appropriate nomenclature for the different variants.

Numerous SARS-CoV-2 variants have emerged over the last several months. The authors note that the variants known as B.1.1.7 (first identified in the United Kingdom) and B.1.351 (first identified in South Africa) concern scientists because of emerging data suggesting their increased transmissibility.

Variants can carry several different mutations, but changes in the spike protein of the virus, used to enter cells and infect them, are especially concerning. Changes to this protein may cause a vaccine to be less effective against a particular variant. The authors note that the B.1.351 variant may be partially or fully resistant to certain SARS-CoV-2 monoclonal antibodies currently authorized for use as therapeutics in the United States.

The recognition of all new variants, including a novel emergent strain (20C/S:452R) in California, requires systematic evaluation, according to the authors. The rise of these variants is a reminder that as long as SARS-CoV-2 continues to spread, it has the potential to evolve into new variants, the authors stress. Therefore, the fight against SARS-CoV-2 and COVID-19 will require robust surveillance, tracking, and vaccine deployment worldwide.

The authors also note the need for a pan-coronavirus vaccine. Once researchers know more about how the virus changes as it spreads, it may be possible to develop a vaccine that protects against most or all variants. While similar research programs are already in place for other diseases, such as influenza, the changing nature of SARS-CoV-2 indicates that they will be necessary for this virus.

SOURCE

https://www.nih.gov/news-events/news-releases/nih-experts-discuss-sars-cov-2-viral-variants

 

Editorial
February 11, 2021

SARS-CoV-2 Viral Variants—Tackling a Moving Target

JAMAPublished online February 11, 2021. doi:10.1001/jama.2021.2088

In this issue of JAMA, Zhang and colleagues1 report the emergence of a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant in Southern California that accounted for 44% (37 of 85) of samples collected and studied in January 2021. The terminology of viral variation can be confusing because the media and even scientific communications often use the terms variantstrain, and lineage interchangeably. The terminology reflects the basic replication biology of RNA viruses that results in the introduction of mutations throughout the viral genome. When specific mutations, or sets of mutations, are selected through numerous rounds of viral replication, a new variant can emerge. If the sequence variation produces a virus with distinctly different phenotypic characteristics, the variant is co-termed a strain. When through genetic sequencing and phylogenetic analysis a new variant is detected as a distinct branch on a phylogenetic tree, a new lineage is born.

New variants become predominant through a process of evolutionary selection that is not well understood. Once identified, several questions arise regarding the potential clinical consequences of a new variant: Is it more readily transmitted; is it more virulent or pathogenic; and can it evade immunity induced by vaccination or prior infection? For these reasons, new viral variants are studied, leading to the terms variant under investigation or variant of concern.

To communicate effectively about new SARS-CoV-2 variants, a common nomenclature is needed, which like the virus, is evolving. Fortunately, the World Health Organization (WHO) is working on a systematic nomenclature that does not require a geographic reference, since viral variants can spread rapidly and globally. Currently, the terminology is overlapping, as reflected in the report by Zhang et al.1 This new variant (CAL.20C) is termed lineage 20C/S:452R in Nextstrain nomenclature,2 referring to the parent clade 20C and spike alteration 452R. Similarly, using a distinct PANGO nomenclature,3 this variant derives from lineage B (B.1.429 and B.1.427). While alterations in any viral genes can have implications for pathogenesis, those arising in the spike protein that mediates viral entry into host cells and is a key target of vaccines and monoclonal antibodies are of particular interest. The new variant, identified in California and termed 20C/S:452R, has 3 amino acid changes in the spike protein, represented using the single-letter amino acid nomenclature: S13I, W152C, and L452R. To interpret this new set of alterations, it is useful to review what is known about recent variants that have become predominant in other regions of the world.

During the early phase of the SARS-CoV-2 pandemic, there were only modest levels of genetic evolution; however, more recent information indicates that even a single amino acid substitution can have biological implications. Starting in April 2020, the original SARS-CoV-2 strain was replaced in many regions of the world by a variant called D614G, which was subsequently shown to increase the efficiency of viral replication in humans and was more transmissible in animal models.46 The D614G strain appears to position its receptor binding domain to interact more efficiently with the ACE2 receptor, and it is associated with higher nasopharyngeal viral RNA loads, which may explain its rise to dominance.

In October 2020, sequencing analysis in the UK detected an emerging variant, later termed B.1.1.7 or 20I/501Y.V1, which is now present and rapidly spreading in many countries.7 B.1.1.7 contains 8 mutations in the spike protein and maintains the D614G mutation. One of these, N501Y, appears to further increase the spike protein interaction with the ACE2 receptor. Epidemiological studies indicate that the B.1.1.7/20I/501Y.V1 strain is 30% to 80% more effectively transmitted and results in higher nasopharyngeal viral loads than the wild-type strain of SARS-CoV. Also of concern are retrospective observational studies suggesting an approximately 30% increased risk of death associated with this variant.8

Another notable variant, 20H/501Y.V2 or B.1.351, was first identified is South Africa, where it has rapidly become the predominant strain.9 Cases attributed to this strain have been detected in multiple countries outside of South Africa, including recent cases in the US. B.1.351 shares the D614G and N501Y mutations with B.1.1.1.7; thus, it is thought to also have a high potential for transmission. There are no data yet to suggest an increased risk of death due to this variant. Importantly, this constellation of mutations—9 total in the spike protein—add yet another dimension of concern. B.1.351 strains are less effectively neutralized by convalescent plasma from patients with coronavirus disease 2019 (COVID-19) and by sera from those vaccinated with several vaccines in development.1012 The decrement in neutralization can be more than 10-fold with convalescent plasma and averages 5- to 6-fold less with sera from vaccinated individuals. Fortunately, neutralization titers induced by vaccination are high, and even with a 6-fold decrease, serum can still effectively neutralize the virus.

Nonetheless, these data are concerning because they indicate that viral variation can result in antigenic changes that alter antibody-mediated immunity. This is highlighted by in vitro studies showing the B.1.351 strain to be partially or fully resistant to neutralization by certain monoclonal antibodies, including some authorized for therapeutic use in the US.12 The prevalent strains in the US appear to remain sensitive to therapeutic monoclonal antibodies; however, recent evolutionary history raises the concern that the virus could be only a few mutations away from more substantive resistance.

COVID-19 vaccine development has been an extraordinary success; however, it is unclear how effective these vaccines will be against the new variants. The interim data from 2 randomized placebo-controlled vaccine studies, the rAd26 from Janssen and a recombinant protein from Novavax, offer some insight. The Janssen study included sites in the US, Brazil, and South Africa with efficacy against COVID-19 at 72%, 66%, and 57%, respectively.13 Novavax reported efficacy from studies in the UK and South Africa with overall efficacy of 89% and 60%, respectively.14 Viral sequence data from infected patients showed that the B.1.351 strain was responsible for the majority of infections in South Africa. Lower vaccine efficacy in the South Africa cohort could be related to antigenic variation or to geographic or population differences. Despite the reduced efficacy, the rAd26 vaccine was 85% effective overall in preventing severe COVID-19, and protection was similar in all regions.

These data suggest that current vaccines could retain the ability to prevent hospitalizations and deaths, even in the face of decreased overall efficacy due to antigenic variation. It is unclear whether changes in vaccine composition will be needed to effectively control the COVID-19 pandemic; however, it is prudent to be prepared. Some companies have indicated plans to manufacture and test vaccines based on emerging variants, and such studies will provide important information on the potential to broaden the immune response.

The recognition of a novel emergent variant, 20C/S:452R, in the most populous US state necessitates further investigation for implications of enhanced transmission. In particular, the L452R mutation in the spike protein could affect the binding of certain therapeutic monoclonal antibodies. The emergence of this and other new variants is likely to be a common occurrence until the spread of this virus is reduced. This emphasizes the importance of a global approach to surveillance, tracking, and vaccine deployment. The approach should be systematic and include in vitro assessment of sensitivity to neutralization by monoclonal antibodies and vaccinee sera, vaccine protection of animals against challenge with new strains, and field data defining viral sequences from breakthrough infections in vaccinees. The infrastructure and process used for tracking and updating influenza vaccines could be used to inform that process. Finally, SARS-CoV-2 will be with the global population for some time and has clearly shown its tendency toward rapid antigenic variation, providing a “wake-up call” that a sustained effort to develop a pan-SARS-CoV-2 vaccine is warranted.

SOURCE

https://jamanetwork.com/journals/jama/fullarticle/2776542

Other related articles published in this Open Access Online Scientific Journal include the following:

Rise of a trio of mutated viruses hints at an increase in transmissibility, speeding the virus’ leaps from one host to the next

Reporter: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2021/02/01/rise-of-a-trio-of-mutated-viruses-hints-at-an-increase-in-transmissibility-speeding-the-virus-leaps-from-one-host-to-the-next/

 

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Comparing COVID-19 Vaccine Schedule Combinations, or “Com-COV” – First-of-its-Kind Study will explore the Impact of using eight different Combinations of Doses and Dosing Intervals for Different COVID-19 Vaccines

Reporter: Aviva Lev-Ari, PhD, RN

 

The UK’s COVID-19 vaccine rollout commenced in December, and requires an individual to receive two doses of the same vaccine, either Pfizer/BioNTech’s BNT162b2 or AstraZeneca/Oxford’s ChAdOx1, with a maximum interval of 12 weeks between doses. As of February 3, 10 million first doses have been administered.

Com-COV has been classified as an “Urgent Public Health” study by the National Institutes for Health and Research (NIHR), and it’s hoped that the data produced may offer greater flexibility for vaccine delivery going forward.

“Given the inevitable challenges of immunizing large numbers of the population against COVID-19 and potential global supply constraints, there are definitely advantages to having data that could support a more flexible immunization program, if ever needed and approved by the medicines regulator,” Jonathan Van-Tam, deputy chief medical officer and senior responsible officer for the study, said in a press release.

The study will run for a 13-month period and will recruit over 800 patients across eight sites in the UK, including London – St George’s and UCL, Oxford, Southampton, Birmingham, Bristol, Nottingham and Liverpool.

Com-COV has eight different arms that will test eight different combinations of doses and dose intervals. This is tentative and subject to change should more COVID-19 vaccines be approved for use in the UK. The eight arms include the following dose combinations:

  • Pfizer/BioNTech and Pfizer/BioNTech – 28 days apart
  • Pfizer/BioNTech and Pfizer/BioNTech – 12 weeks apart – (control group)
  • Oxford/AstraZeneca and Oxford/AstraZeneca – 28 days apart
  • Oxford/AstraZeneca and Oxford/AstraZeneca – 12 weeks apart – (control group)
  • Oxford/AstraZeneca and Pfizer/BioNTech – 28 days apart
  • Oxford/AstraZeneca and Pfizer/BioNTech – 12 weeks apart
  • Pfizer/BioNTech and Oxford/AstraZeneca – 28 days apart
  • Pfizer/BioNTech and Oxford/AstraZeneca – 12 weeks apart

Aside from the logistical benefits of using alternative vaccines, there is scientific value to exploring how different vaccines and doses affect the human immune system.

Dr Peter English, consultant in communicable disease control, pointed out that the antigen used across the currently authorized COVID-19 vaccines is the same Spike protein. Therefore, the immune system can be expected to respond just as well if a different product is used for boosting. “It is also the case that many vaccines work better if a different vaccine is used for boosting – an approach described as heterologous boosting,” English said, referencing previously successful trials using Hepatitis B vaccines.

“It is also even possible that by combining vaccines, the immune response could be enhanced giving even higher antibody levels that last longer; unless this is evaluated in a clinical trial we just won’t know,” added Van-Tam.

If warranted by the study data, the Medicines and Healthcare products Regulatory Agency may consider reviewing and authorizing modifications to the UK’s vaccine regimen approach – but only time will tell.

“We need people from all backgrounds to take part in this trial, so that we can ensure we have vaccine options suitable for all. Signing up to volunteer for vaccine studies is quick and easy via the NHS Vaccine Research Registry,” Professor Andrew Ustianowski, national clinical lead for the NIHR COVID Vaccine Research Program, said

SOURCE

First-of-its-Kind Study Will Test Combination of Different COVID-19 Vaccines | Technology Networks

https://www.technologynetworks.com/biopharma/news/first-of-its-kind-study-will-test-combination-of-different-covid-19-vaccines-345245?utm_campaign=NEWSLETTER_TN_Biopharma

WATCH VIDEO

Different Types of COVID-19 Vaccines With Dr Seth Lederman Video | Technology Networks

https://www.technologynetworks.com/biopharma/videos/different-types-of-covid-19-vaccines-with-dr-seth-lederman-345207

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Rise of a trio of mutated viruses hints at an increase in transmissibility, speeding the virus’ leaps from one host to the next

Reporter: Aviva Lev-Ari, PhD, RN

“We have uncontrolled viral spread in much of the world,” says Adam Lauring, an infectious disease physician and virologist at the University of Michigan. “So the virus has a lot of opportunity to evolve.”

“The variants may be more transmissible, but physics has not changed,” says Müge Çevik, an infectious disease physician at the University of St. Andrews in Scotland.

Many changes don’t affect the virus’ function, and some even harm SARS-CoV-2’s ability to multiply, but they keep happening. “Viruses mutate; that’s what they do,” says Akiko Iwasaki, an immunologist at Yale School of Medicine in Connecticut.

U.K., Brazil, and South Africa. In the United Kingdom, variant B.1.1.7 likely drove the region’s record-setting spike of COVID-19 cases in January. The variant is now circulating in more than 60 countries, including the United States—and projections suggest it will become the most common virus variety in the U.S. by mid-March.

An independently arising lineage called P.1 might also be driving a wave of cases in Manaus, Brazil, where it accounted for nearly half of new COVID-19 infections in December. On January 26, Minnesotan officials reported the first U.S. case of P.1 in a resident who previously traveled to Brazil. And a third lineage raising alarms, known as B.1.351, was first spotted amid a December wave of infections in South Africa. On January 28, the first known U.S. cases of the variant were reported in South Carolina.

One specific mutation, known as N501Y, popped up independently in all three variants, suggesting it could provide an advantage to the virus. “That’s a sign that there is natural selection going on,” Lauring says. The N501Y mutation affects the virus’ spike protein, which is the key it uses to unlock entry into its host’s cells.

Another possibility is that new variants cause people who are infected to harbor more copies of the virus. This results in greater viral “shedding” in airborne droplets spewed when people talk, sing, cough, and breath.

mutations in 501Y.V2 could diminish the effectiveness of antibodies in the blood of people previously infected with the virus. But understanding whether that could lead to more re-infections, or if it could affect vaccine efficacy.

Dramatically scale up production of high-filtration masks for the general public.

Based on:

Why some coronavirus variants are more contagious‹and how we can stop them

https://www.nationalgeographic.com/science/2021/01/why-some-coronavirus-variants-are-more-contagious/?cmpid=org=ngp::mc=crm-email::src=ngp::cmp=editorial::add=SpecialEdition_20210129

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Inflammation and potential links with the microbiome: Mechanisms of infection by SARS-CoV-2

Reporter: Aviva Lev-Ari, PhD, RN

Mechanisms of infection by SARS-CoV-2, inflammation and potential links with the microbiome

Published Online:https://doi.org/10.2217/fvl-2020-0310

Human coronaviruses (HCoVs) were first isolated from patients with the common cold in the 1960s [1–3]. Seven HCoVs known to cause disease in humans have since been identified: HCoV-229E, HCoV-NL63, HCoV-OC43, HCoV-HKU1, the SARS coronavirus (SARS-CoV), the Middle East respiratory syndrome coronavirus and the novel SARS-CoV-2 [4]. The latter was identified after a spike in cases of pneumonia of unknown etiology in Wuhan, Hubei Province, China during December 2019 and was initially named novel coronavirus (2019-nCoV) [5,6]. The virus was renamed SARS-CoV-2 according to the International Committee on Taxonomy of Viruses classification criteria due to its genomic closeness to SARS-CoV; the disease caused by this virus was named coronavirus disease (COVID-19) according to the WHO criteria for naming emerging diseases [7]. SARS-CoV-2 belongs to the genera Betacoronavirus and shares a different degree of genomic similarity with the other two epidemic coronaviruses: SARS-CoV (∼79%) and Middle East respiratory syndrome coronavirus (∼50%) [8].

COVID-19 has caused considerable morbidity and mortality worldwide and has become the central phenomenon that is shaping our current societies. Human-to-human transmission is the main route of spread of the virus, mainly through direct contact, respiratory droplets and aerosols [9–12]. Management of COVID-19 has been extremely challenging due to its high infectivity, lack of effective therapeutics and potentially small groups of individuals (i.e., asymptomatic or mild disease) rapidly spreading the disease [13–17]. Although research describing COVID-19 and the mechanisms of infection by SARS-CoV-2 and its pathogenesis has expanded rapidly, there is still much to be learnt. Important gaps in knowledge which remain to be elucidated are the dynamic and complex interactions between the virus and the host’s immune system, as well as the potential interspecies communications occurring between ecological niches encompassing distinct microorganisms in both healthy individuals and persons living with chronic diseases, and how these interactions could determine or modulate disease progression and outcomes.

In this review, we describe recent insights into these topics, as well as remaining questions whose answers will allow us to understand how interactions between the virus, the immune system and microbial components could possibly be related to disease states in patients with COVID-19, as well as existing studies of the microbiome in patients with COVID-19.

SOURCE

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Mechanistic link between SARS-CoV-2 infection and increased risk of stroke using 3D printed models and human endothelial cells

Reporter: Adina Hazan, PhD

 

Kaneko, et al.  from UCLA aimed to explore why SARS-CoV-2 infection is associated with an increased rate of cerebrovascular events, including

  • ischemic stroke and
  • intracerebral hemorrhage

While some suggested mechanisms include an overall systemic inflammatory response including increasing circulating cytokines and leading to a prothrombotic state, this may be only a partial answer. A SARS-CoV-2 specific mechanism could be likely, considering that both angiotensin-converting enzyme-2 (ACE2), the receptor necessary for SARS-CoV-2 to gain entry into the cell, and SARS-CoV-2 RNA have been reportedly detected in the human brain postmortem.

One of the difficulties in studying vasculature mechanisms is that the inherent 3D shape and blood flow subject this tissue to different stressors, such as flow, that could be critically relevant during inflammation. To accurately study the effect of SARS-CoV-2 on the vasculature of the brain, the team generated 3D models of the human middle cerebral artery during intracranial artery stenosis using data from CT (computed tomography) angiography. This data was then exported with important factors included such as

  • shear stress during perfusion,
  • streamlines, and
  • flow velocity to be used to fabricate 3D models.

These tubes were then coated with endothelial cells isolated and sorted from normal human brain tissue resected during surgery. In doing so, this model could closely mimic the cellular response of the vasculature of the human brain.

Surprisingly, without this 3D tube, human derived brain endothelial cells displayed very little expression of ACE2 or, TMPRSS2 (transmembrane protease 2), a necessary cofactor for SARS-COV-2 viral entry.

Interestingly,

  • horizontal shear stress increased the expression of ACE2 and
  • increased the binding of spike protein to ACE2, especially within the stenotic portion of the 3D model.

By exposing the endothelial cells to liposomes expressing the SARS-CoV-2 spike protein, they also were able to explore key upregulated genes in the exposed cells, in which they found that

  • “binding of SARS-CoV-2 S protein triggered 83 unique genes in human brain endothelial cells”.

This included many inflammatory signals, some of which have been previously described as associated with SARS-COV-2, and others whose effects are unknown. This may provide an important foundation for exploring potential therapeutic targets in patients susceptible to cerebrovascular events.

Overall, this study shows important links between the

  • mechanisms of SARS-CoV-2 and the
  • increase in ischemic events in these patients. It also has important implications for
  • treatment for SARS-CoV-2, as high blood pressure and atherosclerosis may be increasing ACE2 expression in patients, providing the entry port for viral particles into brain endothelia.

SOURCE:

https://www.ahajournals.org/doi/10.1161/STROKEAHA.120.032764

Other related articles published in this Open Access Online Scientific Journal include the following:

The Impact of COVID-19 on the Human Heart

Reporters: Justin D. Pearlman, MD, PhD, FACC and Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2020/09/29/the-impact-of-covid-19-on-the-human-heart/

 

SAR-Cov-2 is probably a vasculotropic RNA virus affecting the blood vessels: Endothelial cell infection and endotheliitis in COVID-19

Reporter: Aviva Lev-Ari, PhD, RN – Bold face and colors are my addition

https://pharmaceuticalintelligence.com/2020/06/01/sar-cov-2-is-probably-a-vasculotropic-rna-virus-affecting-the-blood-vessels-endothelial-cell-infection-and-endotheliitis-in-covid-19/

 

Diagnosis of Coronavirus Infection by Medical Imaging and Cardiovascular Impacts of Viral Infection, Aviva Lev-Ari, PhD, RN  Lead Curator – e–mail: avivalev-ari@alum.berkeley.edu

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COVID-19 T-cell immune response map, immunoSEQ T-MAP COVID for research of T-cell response to SARS-CoV-2 infection

Reporter: Aviva Lev-Ari, PhD, RN

 

Read our latest blog | T cells: Understanding Exposure and Immunity to COVID-19 by Adaptive Co-Founder and CSO, Harlan Robins. Read here

Watch the video

T cells are the adaptive immune system’s first responders to any virus, circulating in the blood to detect and quickly multiply to attack the virus, often before symptoms appear. Adaptive Biotechnologies’ unique MIRA Technology and immunoSEQ Technology has enabled us to create a comprehensive view of the T-cell response to SARS-CoV-2 infection. This data has been made public as part of the ImmuneCODE Initiative in order to help propel drug, vaccine, and clinical trial research. We are launching immunoSEQ T-MAP COVID with the tools to study and analyze the COVID-19 T-cell immune response map.

SARS-CoV-2-specific Antigen-TCR sequence-level data
Quantitative sequence level data for TCR repertoires for SARS-CoV-2 specific antigens
Monitor immunologic response to SARS-CoV-2 infection or vaccine
Track COVID-19 specific TCR sequences longitudinally
Dive into Patient, Population, or Cohort-level data
Determine TCR clones shared between cohorts & those that are Public vs Private clones

 

Learn more about the science behind the ImmuneCODE database in our first publication (Nolan et al.) and to discover initial COVID-19 data insights, read our recently updated pre-print publication (Snyder et al.)

A large-scale database of T-cell receptor beta (TCRβ) sequences and binding associations from natural and synthetic exposure to SARS-CoV-2

Magnitude and Dynamics of the T-Cell Response to SARS-CoV-2 Infection at Both Individual and Population Levels

End-to-end solution; from experimental design to publication ready data

SARS-CoV-2-specific TCR repertoire sequences & antigen data

✔  Validated TCR-antigen data from over 70 MIRA experiments

✔  In vivo identified SARS-CoV-2-specific TCR sequences

✔  TCR-Antigen sequence level data with the PCR, bias-controlled, reproducible immunoSEQ Assay

Data analysis through the immunoSEQ Analyzer or Computational Biology Services

✔  Explore SARS-CoV-2-specific TCR-Antigen sequence data in the immunoSEQ Analyzer

✔  Compare your COVID-19 samples against our COVID-19 samples to identify public vs private clones

✔  Computational Biology Services for COVID-19 data and Metadata analysis

Comprehensive COVID-19 TCR-Antigen sequence database

✔  Providing you a comprehensive view of SARS-CoV-2-specific antigen and TCR level data

✔  Database will constantly be updated with new findings and TCR-Antigen sequence data

 

Check out the publications below to learn how researchers are propelling their COVID-19 research by leveraging immunoSEQ T-MAP COVID and the ImmuneCODE COVID-19 database

Analysis of SARS-CoV-2 specific T-cell receptors in ImmuneCode reveals cross-reactivity to immunodominant Influenza M1 epitope

 

Watch our video, about how the immunoSEQ Technology and immunoSEQ T-MAP COVID can be used to better understand the immune response to SARS-CoV-2 infection.

 

Ready to learn more about how our immunoSEQ T-MAP COVID service can help you propel your research forward? Contact us below to speak with one of our experts.

SOURCE

https://ww2.adaptivebiotech.com/immunoseq-TMAP-COVID?utm_source=genomeweb&utm_medium=email&utm_campaign=dailynews

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From AAAS Science News on COVID19: New CRISPR based diagnostic may shorten testing time to 5 minutes

Reporter: Stephen J. Williams, Ph.D.

 

 

 

 

 

 

 

 

 

A new CRISPR-based diagnostic could shorten wait times for coronavirus tests.

 

 

New test detects coronavirus in just 5 minutes

By Robert F. ServiceOct. 8, 2020 , 3:45 PM

Science’s COVID-19 reporting is supported by the Pulitzer Center and the Heising-Simons Foundation.

 

Researchers have used CRISPR gene-editing technology to come up with a test that detects the pandemic coronavirus in just 5 minutes. The diagnostic doesn’t require expensive lab equipment to run and could potentially be deployed at doctor’s offices, schools, and office buildings.

“It looks like they have a really rock-solid test,” says Max Wilson, a molecular biologist at the University of California (UC), Santa Barbara. “It’s really quite elegant.”

CRISPR diagnostics are just one way researchers are trying to speed coronavirus testing. The new test is the fastest CRISPR-based diagnostic yet. In May, for example, two teams reported creating CRISPR-based coronavirus tests that could detect the virus in about an hour, much faster than the 24 hours needed for conventional coronavirus diagnostic tests.CRISPR tests work by identifying a sequence of RNA—about 20 RNA bases long—that is unique to SARS-CoV-2. They do so by creating a “guide” RNA that is complementary to the target RNA sequence and, thus, will bind to it in solution. When the guide binds to its target, the CRISPR tool’s Cas13 “scissors” enzyme turns on and cuts apart any nearby single-stranded RNA. These cuts release a separately introduced fluorescent particle in the test solution. When the sample is then hit with a burst of laser light, the released fluorescent particles light up, signaling the presence of the virus. These initial CRISPR tests, however, required researchers to first amplify any potential viral RNA before running it through the diagnostic to increase their odds of spotting a signal. That added complexity, cost, and time, and put a strain on scarce chemical reagents. Now, researchers led by Jennifer Doudna, who won a share of this year’s Nobel Prize in Chemistry yesterday for her co-discovery of CRISPR, report creating a novel CRISPR diagnostic that doesn’t amplify coronavirus RNA. Instead, Doudna and her colleagues spent months testing hundreds of guide RNAs to find multiple guides that work in tandem to increase the sensitivity of the test.

In a new preprint, the researchers report that with a single guide RNA, they could detect as few as 100,000 viruses per microliter of solution. And if they add a second guide RNA, they can detect as few as 100 viruses per microliter.

That’s still not as good as the conventional coronavirus diagnostic setup, which uses expensive lab-based machines to track the virus down to one virus per microliter, says Melanie Ott, a virologist at UC San Francisco who helped lead the project with Doudna. However, she says, the new setup was able to accurately identify a batch of five positive clinical samples with perfect accuracy in just 5 minutes per test, whereas the standard test can take 1 day or more to return results.

The new test has another key advantage, Wilson says: quantifying a sample’s amount of virus. When standard coronavirus tests amplify the virus’ genetic material in order to detect it, this changes the amount of genetic material present—and thus wipes out any chance of precisely quantifying just how much virus is in the sample.

By contrast, Ott’s and Doudna’s team found that the strength of the fluorescent signal was proportional to the amount of virus in their sample. That revealed not just whether a sample was positive, but also how much virus a patient had. That information can help doctors tailor treatment decisions to each patient’s condition, Wilson says.

Doudna and Ott say they and their colleagues are now working to validate their test setup and are looking into how to commercialize it.

Posted in:

doi:10.1126/science.abf1752

Robert F. Service

Bob is a news reporter for Science in Portland, Oregon, covering chemistry, materials science, and energy stories.

 

Source: https://www.sciencemag.org/news/2020/10/new-test-detects-coronavirus-just-5-minutes

Other articles on CRISPR and COVID19 can be found on our Coronavirus Portal and the following articles:

The Nobel Prize in Chemistry 2020: Emmanuelle Charpentier & Jennifer A. Doudna
The University of California has a proud legacy of winning Nobel Prizes, 68 faculty and staff have been awarded 69 Nobel Prizes.
Toaster Sized Machine Detects COVID-19
Study with important implications when considering widespread serological testing, Ab protection against re-infection with SARS-CoV-2 and the durability of vaccine protection

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