Cross-reactivity of SARS-CoV structural protein antibodies against SARS-CoV-2

Bates, Timothy A.; Weinstein, Jules B.; Farley, Scotland; Leier, Hans C.; Messer, William B.; Tafesse, Fikadu G.

In the ongoing COVID-19 pandemic, there remain unanswered questions regarding the nature and significance of the humoral immune response towards other coronavirus infections. Here, we investigate the cross-reactivity of antibodies raised against the first SARS-CoV for their reactivity towards SARS-CoV-2. We extensively characterize a selection of 10 antibodies covering all of the SARS-CoV structural proteins: spike, membrane, nucleocapsid, and envelope. While nearly all of the examined SARS-CoV antibodies displayed some level of reactivity to SARS-CoV-2, we found only partial cross-neutralization for the spike antibodies. The implications of our work are two-fold. Firstly, we have established a set of antibodies with known reactivity to both SARS-CoV and SARS-CoV-2, which will allow further study of both viruses. Secondly, we provide empirical evidence of the high propensity for antibody cross-reactivity between distinct strains of human coronaviruses, critical information for designing diagnostic and vaccine strategies for COVID-19.