Naive human B cells can neutralize SARS-CoV-2 through recognition of its receptor binding domain (preprint)

ABSTRACT

Exposure to a pathogen elicits an adaptive immune response aimed to control and eradicate. This initial exposure is imprinted on the immune system, so that a subsequent encounter to the same pathogen or a variant will result in a memory recall response that is often protective. Interrogating the naive B cell repertoire in terms of both abundance and specificity to said pathogen may contribute to an understanding of how to potentially elicit protective responses. Here, we isolated naive B cells across 8 human donors, targeting the SARS-CoV-2 receptor-binding domain (RBD). Single B cell sorting, and subsequent sequence analysis, showed diverse gene usage and pairing with no apparent restriction on complementarity determining region length in either the heavy or light chains. We show that recombinantly expressed IgGs and Fabs of these germline precursors bind SARS-CoV-2 RBD. Importantly, a subset of these naive antibodies also bind SARS-CoV, an emergent variant (501Y.V2) and a potential pandemic (WIV-1) coronavirus. Furthermore, naive antibodies can also neutralize SARS-CoV-2 pseudoviruses in the absence of any somatic hypermutation, suggesting that protective immunity to coronaviruses, more broadly, may be genetically encoded. Future studies aimed at understanding the naive repertoire to other coronaviruses may ultimately reveal shared specificities that could be leveraged to develop pan-coronavirus vaccines aimed at priming encoded germline responses.