SARS-CoV-2 mRNA vaccines have demonstrated high efficacy and immunogenicity, but limited information is currently available on memory B cell generation and long-term persistence. Here, we investigated spike-specific memory B cells and humoral responses in 145 subjects, up to 6 months after the BNT162b2 vaccine (Comirnaty) administration. Spike-specific antibodies peaked 7 days after the second dose and significant antibody titers and ACE2/RBD binding inhibiting activity were still observed after 6 months, despite a progressive decline over time. Concomitant to antibody reduction, spike-specific memory B cells, mostly IgG class-switched, increased in the blood of vaccinees and persisted 6 months after vaccination. Following the in vitro restimulation, circulating memory B cells reactivated and produced spike-specific antibodies. A high frequency of spike-specific IgG + plasmablasts, identified by computational analysis 7 days after boost, positively correlated with the generation of IgG + memory B cells at 6 months. These data demonstrate that mRNA BNT162b2 vaccine elicits strong B cell immunity with spike-specific memory B cells that still persist 6 months after vaccination, playing a crucial role for a rapid response to SARS-CoV-2 virus encounter.
【저자키워드】 COVID-19, SARS-CoV-2, BNT162b2 vaccine, vaccination, memory B cells, 【초록키워드】 antibodies, IgG, Efficacy, Immunity, antibody, mRNA vaccine, mRNA BNT162b2 vaccine, SARS-CoV-2 virus, in vitro, B cell, Humoral response, persistence, plasmablasts, Antibody titer, information, Blood, boost, memory B cell, binding, administration, Frequency, rapid response, reduction, second dose, circulating, Concomitant, computational analysis, spike-specific IgG, Spike-specific antibody, Cell, memory B, vaccinee, produced, investigated, peaked, subjects, demonstrated, elicit, inhibiting, positively correlated, 【제목키워드】 memory B cells, BNT162b2 mRNA, evidence of, Month,