Coronavirus-Specific Antibody Cross Reactivity in Rhesus Macaques following SARS-CoV-2 Vaccination and Infection

Vaccines are being rapidly developed with the goal of ending the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. However, the extent to which SARS-CoV-2 vaccination induces serum responses that cross-react with other coronaviruses remains poorly studied. Here, we define serum profiles in rhesus macaques after vaccination with DNA- or Ad26-based vaccines expressing SARS-CoV-2 spike protein followed by SARS-CoV-2 challenge, or SARS-CoV-2 infection alone. Analysis of serum responses showed robust reactivity to the SARS-CoV-2 full-length spike protein and receptor binding domain (RBD), both included in the vaccine. However, serum cross-reactivity to the closely related sarbecovirus SARS-CoV-1 spike and RBD was reduced. Reactivity was also measured to the distantly related common cold alphacoronavirus (229E and NL63) and betacoronavirus (OC43 and HKU1) spike proteins. Using SARS-CoV-2 and SARS-CoV-1 lentivirus-based pseudoviruses, we show that neutralizing antibody responses were predominantly SARS-CoV-2 specific. These data define patterns of cross-reactive binding and neutralizing serum responses induced by SARS-CoV-2 infection and vaccination in rhesus macaques. Our observations have important implications for understanding polyclonal responses to the SARS-CoV-2 spike protein, which will facilitate future CoV vaccine assessment and development. IMPORTANCE The rapid development and deployment of SARS-CoV-2 vaccines has been unprecedented. In this study, we explore the cross-reactivity of SARS-CoV-2-specific antibody responses to other coronaviruses. By analyzing responses from nonhuman primates (NHPs) both before and after immunization with DNA or Ad26-vectored vaccines, we find patterns of cross-reactivity that mirror those induced by SARS-CoV-2 infection. These data highlight the similarities between infection and vaccine-induced humoral immunity for SARS-CoV-2 and cross-reactivity of these responses to other CoVs.