B Cell Memory Repertoire Following CoronaVac Vaccination

This study focuses on analyzing the B-cell memory repertoire after two doses of the inactivated SARS-CoV-2 vaccine CoronaVac. Memory B cells were isolated and stimulated in vitro before deep sequencing of the Heavy Chain Variable (VH) repertoire in vaccinated individuals, compared to a pre-pandemic control group. The results indicated a shift in the VH repertoire, with a notable increase in HCDR3 length and the enrichment of specific VH gene segments (IGVH3-23, 3-30, 3-7, 3-72, 3-74 for IgA and IGHV4-39 and 4-59 for IgG). The study also observed a significant expansion of IgA clones in vaccinated individuals and a high degree of sharing between memory B cells from different vaccinees. Additionally, a strong convergence was found between the B-cell repertoires of vaccinees and SARS-CoV-2 neutralizing antibody sequences present in the CoV-AbDab database. These findings support the ability of CoronaVac to elicit antibodies with characteristics similar to known neutralizing antibodies, underscoring its protective efficacy against COVID-19. The data contributes to understanding how CoronaVac influences the memory B cell repertoire, providing insights into its role in long-term immune protection.