Epidemiological studies and clinical trials suggest Bacillus Calmette-Guérin (BCG) vaccine has protective effects against coronavirus disease 2019 (COVID-19). There are now over 30 clinical trials evaluating if BCG vaccination can prevent or reduce the severity of COVID-19. However, the mechanism by which BCG vaccination can induce severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T cell responses is unknown. Here, we identify 8 novel BCG-derived peptides with significant sequence homology to either SARS-CoV-2 NSP3 or NSP13-derived peptides. Using an in vitro co-culture system, we show that human CD4+ and CD8+ T cells primed with a BCG-derived peptide developed enhanced reactivity to its corresponding homologous SARS-CoV-2-derived peptide. As expected, HLA differences between individuals meant that not all persons developed immunogenic responses to all 8 BCG-derived peptides. Nevertheless, all of the 20 individuals that were primed with BCG-derived peptides developed enhanced T cell reactivity to at least 7 of 8 SARS-CoV-2-derived peptides. These findings provide an in vitro mechanism that may account, in part, for the epidemiologic observation that BCG vaccination confers some protection from COVID-19.
【저자키워드】 COVID-19, Vaccine, cross-protection, T cell, heterologous immunity, BCG, 【초록키워드】 coronavirus disease, SARS-CoV-2, coronavirus, clinical trial, peptide, in vitro, severity of COVID-19, response, peptides, HLA, homologous, mechanism, T cell response, CD8+ T cell, protective effect, observation, BCG vaccination, acute respiratory syndrome, individual, CD4+, sequence homology, immunogenic, Bacillus, co-culture, Prevent, identify, induce, reduce, reactivity, expected, 【제목키워드】 SARS-CoV-2, bcg vaccine,