The authors describe their isolation of monoclonal antibodies from three convalescent COVID-19 patients using a SARS-CoV-2 stabilised pre-fusion spike protein. They found that these antibodies have low levels of somatic hypermutation and were very enriched in VH1-69, VH3-30-3 and VH1-24 gene usage. A subset of the antibodies were able to potently inhibit SARS-CoV-2 infection at levels as low as 0.007 μg/mL. Competition and electron microscopy studies found that the SARS-CoV-2 spike protein is made up of multiple distinct antigenic sites, including several receptor-binding domain (RBD) epitopes as well as non-RBD epitopes. Therefore these antibodies are promising therapeutic candidates and provide evidence for vaccine design.
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