Fast-Track Discovery of SARS-CoV-2-Neutralizing Antibodies from Human B Cells by Direct Functional Screening

Abstract

As the COVID-19 pandemic revealed, rapid development of vaccines and therapeutic antibodies are crucial to guarantee a quick return to the status quo of society. In early 2020, we deployed our droplet microfluidic single-cell-based platform DROPZYLLA® for the generation of cognate antibody repertoires of convalescent COVID-19 donors. Discovery of SARS-CoV-2-specific antibodies was performed upon display of antibodies on the surface of HEK293T cells by antigen-specific sorting using binding to the SARS-CoV-2 spike and absence of binding to huACE2 as the sort criteria. This efficiently yielded antibodies within 3–6 weeks, of which up to 100% were neutralizing. One of these, MTX-COVAB, displaying low picomolar neutralization IC50 of SARS-CoV-2 and with a neutralization potency on par with the Regeneron antibodies, was selected for GMP manufacturing and clinical development in June 2020. MTX-COVAB showed strong efficacy in vivo and neutralized all identified clinically relevant variants of SARS-CoV-2 at the time of its selection. MTX-COVAB completed GMP manufacturing by the end of 2020, but clinical development was stopped when the Omicron variant emerged, a variant that proved to be detrimental to all monoclonal antibodies already approved. The present study describes the capabilities of the DROPZYLLA® platform to identify antibodies of high virus-neutralizing capacity rapidly and directly.

Current development of severe acute respiratory syndrome coronavirus 2 neutralizing antibodies (Review)

“…Large-scale preparations of specifically targeting mAbs that are of high purity with potent neutralizing activity can render them powerful tools for the prevention and treatment of infectious diseases ( 23 ). For SARS-CoV-2, specific B cells have been obtained from patients recovered from COVID-19 to produce large quantities of humanized mAbs through numerous methods, including mouse hybridoma fusion, single B cell sorting, phage display and transgenic mice and antibody screening technologies ( 24 – 26 ). A number of NAbs against SARS-CoV-2 have been developed.…”