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1.
Nature ; 597(7874): 97-102, 2021 09.
Article in English | MEDLINE | ID: covidwho-1309448

ABSTRACT

An ideal therapeutic anti-SARS-CoV-2 antibody would resist viral escape1-3, have activity against diverse sarbecoviruses4-7, and be highly protective through viral neutralization8-11 and effector functions12,13. Understanding how these properties relate to each other and vary across epitopes would aid the development of therapeutic antibodies and guide vaccine design. Here we comprehensively characterize escape, breadth and potency across a panel of SARS-CoV-2 antibodies targeting the receptor-binding domain (RBD). Despite a trade-off between in vitro neutralization potency and breadth of sarbecovirus binding, we identify neutralizing antibodies with exceptional sarbecovirus breadth and a corresponding resistance to SARS-CoV-2 escape. One of these antibodies, S2H97, binds with high affinity across all sarbecovirus clades to a cryptic epitope and prophylactically protects hamsters from viral challenge. Antibodies that target the angiotensin-converting enzyme 2 (ACE2) receptor-binding motif (RBM) typically have poor breadth and are readily escaped by mutations despite high neutralization potency. Nevertheless, we also characterize a potent RBM antibody (S2E128) with breadth across sarbecoviruses related to SARS-CoV-2 and a high barrier to viral escape. These data highlight principles underlying variation in escape, breadth and potency among antibodies that target the RBD, and identify epitopes and features to prioritize for therapeutic development against the current and potential future pandemics.


Subject(s)
Broadly Neutralizing Antibodies/immunology , COVID-19/virology , Cross Reactions/immunology , Immune Evasion , SARS-CoV-2/classification , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Adult , Aged , Animals , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/immunology , Antibodies, Viral/chemistry , Antibodies, Viral/immunology , Antibody Affinity , Broadly Neutralizing Antibodies/chemistry , COVID-19/drug therapy , COVID-19/immunology , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/immunology , Cell Line , Cricetinae , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/genetics , Epitopes, B-Lymphocyte/immunology , Female , Humans , Immune Evasion/genetics , Immune Evasion/immunology , Male , Mesocricetus , Middle Aged , Models, Molecular , SARS-CoV-2/chemistry , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Vaccinology
2.
Cell ; 184(5): 1171-1187.e20, 2021 03 04.
Article in English | MEDLINE | ID: covidwho-1051523

ABSTRACT

SARS-CoV-2 can mutate and evade immunity, with consequences for efficacy of emerging vaccines and antibody therapeutics. Here, we demonstrate that the immunodominant SARS-CoV-2 spike (S) receptor binding motif (RBM) is a highly variable region of S and provide epidemiological, clinical, and molecular characterization of a prevalent, sentinel RBM mutation, N439K. We demonstrate N439K S protein has enhanced binding affinity to the hACE2 receptor, and N439K viruses have similar in vitro replication fitness and cause infections with similar clinical outcomes as compared to wild type. We show the N439K mutation confers resistance against several neutralizing monoclonal antibodies, including one authorized for emergency use by the US Food and Drug Administration (FDA), and reduces the activity of some polyclonal sera from persons recovered from infection. Immune evasion mutations that maintain virulence and fitness such as N439K can emerge within SARS-CoV-2 S, highlighting the need for ongoing molecular surveillance to guide development and usage of vaccines and therapeutics.


Subject(s)
COVID-19/immunology , Genetic Fitness , Immune Evasion , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Angiotensin-Converting Enzyme 2/chemistry , Antibodies, Neutralizing/genetics , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/virology , Humans , Mutation , Phylogeny , SARS-CoV-2/chemistry , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/chemistry , Virulence
3.
Media Int. Aust. ; 2020.
Article in English | WHO COVID, ELSEVIER | ID: covidwho-760326

ABSTRACT

In this article, we examine Chinese assessments of Western democratic systems in the context of the COVID-19 pandemic. This research is based on an up-to-date case study of how Chinese Internet users discussed the UK Prime Minister – Boris Johnson’s infection with COVID-19 in late March and early April 2020. The research collected original data from the Chinese community question-answering (CQA) site – Zhihu. Using a mixed-method approach, consisting of content analysis (CA) and thematic analysis (TA), we show how Zhihu users evaluate the incident (1) as a way to express their sentiments towards Boris Johnson, (2) as a case to assess British politics and (3) as a vehicle for rationalizing their views on Western democratic systems in relation to China’s domestic politics. The research findings shed new light on a Chinese gaze at Western democratic systems in the COVID-19 pandemic crisis.

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