PT - JOURNAL ARTICLE AU - Cameroni, Elisabetta AU - Saliba, Christian AU - Bowen, John E. AU - Rosen, Laura E. AU - Culap, Katja AU - Pinto, Dora AU - De Marco, Anna AU - Zepeda, Samantha K. AU - di Iulio, Julia AU - Zatta, Fabrizia AU - Kaiser, Hannah AU - Noack, Julia AU - Farhat, Nisar AU - Czudnochowski, Nadine AU - Havenar-Daughton, Colin AU - Sprouse, Kaitlin R. AU - Dillen, Josh R. AU - Powell, Abigail E. AU - Chen, Alex AU - Maher, Cyrus AU - Yin, Li AU - Sun, David AU - Soriaga, Leah AU - Gustafsson, Claes AU - Franko, Nicholas M. AU - Logue, Jenni AU - Iqbal, Najeeha Talat AU - Mazzitelli, Ignacio AU - Geffner, Jorge AU - Grifantini, Renata AU - Chu, Helen AU - Gori, Andrea AU - Riva, Agostino AU - Giannini, Olivier AU - Ceschi, Alessandro AU - Ferrari, Paolo AU - Franzetti-Pellanda, Alessandra AU - Garzoni, Christian AU - Hebner, Christy AU - Purcell, Lisa A. AU - Piccoli, Luca AU - Pizzuto, Matteo Samuele AU - Walls, Alexandra C. AU - Telenti, Amalio AU - Virgin, Herbert W. AU - Lanzavecchia, Antonio AU - Veesler, David AU - Snell, Gyorgy AU - Corti, Davide TI - Broadly neutralizing antibodies overcome SARS-CoV-2 Omicron antigenic shift AID - 10.1101/2021.12.12.472269 DP - 2021 Jan 01 TA - bioRxiv PG - 2021.12.12.472269 4099 - http://biorxiv.org/content/early/2021/12/14/2021.12.12.472269.short 4100 - http://biorxiv.org/content/early/2021/12/14/2021.12.12.472269.full AB - The recently emerged SARS-CoV-2 Omicron variant harbors 37 amino acid substitutions in the spike (S) protein, 15 of which are in the receptor-binding domain (RBD), thereby raising concerns about the effectiveness of available vaccines and antibody therapeutics. Here, we show that the Omicron RBD binds to human ACE2 with enhanced affinity relative to the Wuhan-Hu-1 RBD and acquires binding to mouse ACE2. Severe reductions of plasma neutralizing activity were observed against Omicron compared to the ancestral pseudovirus for vaccinated and convalescent individuals. Most (26 out of 29) receptor-binding motif (RBM)-directed monoclonal antibodies (mAbs) lost in vitro neutralizing activity against Omicron, with only three mAbs, including the ACE2-mimicking S2K146 mAb1, retaining unaltered potency. Furthermore, a fraction of broadly neutralizing sarbecovirus mAbs recognizing antigenic sites outside the RBM, including sotrovimab2, S2X2593 and S2H974, neutralized Omicron. The magnitude of Omicron-mediated immune evasion and the acquisition of binding to mouse ACE2 mark a major SARS-CoV-2 mutational shift. Broadly neutralizing sarbecovirus mAbs recognizing epitopes conserved among SARS-CoV-2 variants and other sarbecoviruses may prove key to controlling the ongoing pandemic and future zoonotic spillovers.Competing Interest StatementE.C., K.C., C.S., D.P., F.Z., A.D.M., A.L., L.P., M.S.P., D.C., H.K., J.N., N.F., J.diI., L.E.R., N.C., C.H.D., K.R.S., J.R.D., A.E.P., A.C., C.M., L.Y., D.S., L.S., L.A.P., C.H., A.T., H.W.V. and G.S. are employees of Vir Biotechnology Inc. and may hold shares in Vir Biotechnology Inc. L.A.P. is a former employee and shareholder in Regeneron Pharmaceuticals. Regeneron provided no funding for this work. The Veesler laboratory has received a sponsored research agreement from Vir Biotechnology Inc. HYC reported consulting with Ellume, Pfizer, The Bill and Melinda Gates Foundation, Glaxo Smith Kline, and Merck. She has received research funding from Emergent Ventures, Gates Ventures, Sanofi Pasteur, The Bill and Melinda Gates Foundation, and support and reagents from Ellume and Cepheid outside of the submitted work. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.