INTRODUCTION Worldwide appearance of severe acute respiratory syndrome coronavirus
2 (SARS-CoV-2) variants of concern (VOCs) with increased transmissibility and resistance to
therapeutic antibodies necessitates the discovery of broadly reactive antibodies. We isolated
receptor binding domain (RBD) targeting antibodies that potently neutralize 23 variants,
including the B. 1.1. 7, B. 1.351, P. 1, B. 1.429, B. 1.526, and B. 1.617 VOCs. Structural and
functional studies revealed the molecular basis for antibody binding and showed that …

The emergence of highly transmissible SARS-CoV-2 variants of concern (VOC) that are
resistant to therapeutic antibodies highlights the need for continuing discovery of broadly
reactive antibodies. We identify four receptor-binding domain targeting antibodies from three
early-outbreak convalescent donors with potent neutralizing activity against 23 variants
including the B. 1.1. 7, B. 1.351, P. 1, B. 1.429, B. 1.526 and B. 1.617 VOCs. Two antibodies
are ultrapotent, with sub-nanomolar neutralization titers (ICso O. 3 to 11.1 ng/mL; ICgo 1.5 to …