Davide F. Robbiani, Christian Gaebler, Frauke Muecksch, Julio C. C. Lorenzi, Zijun Wang, Alice Cho, Marianna Agudelo, Christopher O. Barnes, Anna Gazumyan, Shlomo Finkin, Thomas Hägglöf, Thiago Y. Oliveira, Charlotte Viant, Arlene Hurley, Hans-Heinrich Hoffmann, Katrina G. Millard, Rhonda G. Kost, Melissa Cipolla, Kristie Gordon, Filippo Bianchini, Spencer T. Chen, Victor Ramos, Roshni Patel, Juan Dizon, Irina Shimeliovich, Pilar Mendoza, Harald Hartweger, Lilian Nogueira, Maggi Pack, Jill Horowitz, Fabian Schmidt, Yiska Weisblum, Eleftherios Michailidis, Alison W. Ashbrook, Eric Waltari, John E. Pak, Kathryn E. Huey-Tubman, Nicholas Koranda, Pauline R. Hoffman, Anthony P. West Jr, Charles M. Rice, Theodora Hatziioannou, Pamela J. Bjorkman, Paul D. Bieniasz, Marina Caskey & Michel C. Nussenzweig
During the coronavirus disease-2019 (COVID-19) pandemic, severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) has led to the infection of millions of people and has claimed hundreds of thousands of lives. The entry of the virus into cells depends on the receptor-binding domain (RBD) of the spike (S) protein of SARS-CoV-2. Although there is currently no vaccine, it is likely that antibodies will be essential for protection. However, little is known about the human antibody response to SARS-CoV-2. Here we report on 149 COVID-19-convalescent individuals. Plasma samples collected an average of 39 days after the onset of symptoms had variable half-maximal pseudovirus neutralizing titres; titres were less than 50 in 33% of samples, below 1,000 in 79% of samples and only 1% of samples had titres above 5,000. Antibody sequencing revealed the expansion of clones of RBD-specific memory B cells that expressed closely related antibodies in different individuals. Despite low plasma titres, antibodies to three distinct epitopes on the RBD neutralized the virus with half-maximal inhibitory concentrations (IC50 values) as low as 2 ng ml^−1. In conclusion, most convalescent plasma samples obtained from individuals who recover from COVID-19 do not contain high levels of neutralizing activity. Nevertheless, rare but recurring RBD-specific antibodies with potent antiviral activity were found in all individuals tested, suggesting that a vaccine designed to elicit such antibodies could be broadly effective.