B cell persistence and evolution to SARS-CoV-2.

Deciphering the persistence of memory responses to COVID-19 will aid in understanding long-term protection. A preprint by Gaebler et al. presents a longitudinal analysis of SARS-CoV-2-specific humoral responses in 87 patients at 1.3 and 6.2 months after infection. Although antibody titres and neutralizing capacity declined over time, memory B cells specific for the receptor-binding domain of SARS-CoV-2 spike protein persisted up to 6 months after infection. These memory B cells display changes in clonal composition and can generate antibodies with increased neutralization potency and breadth. Consistent with continued antibody evolution, intestinal biopsies showed persistence of SARS-CoV-2 antigens 3 months after infection in some individuals. These data suggest that the persistence of memory B cells that continue to evolve could provide effective humoral responses upon virus re-exposure.