Laboratory of Molecular Microbiology and Biotechnology, Department of Medical Biotechnologies, University of Siena, Siena, Italy.
Department of Medical Biotechnologies, University of Siena, Siena, Italy.
Front Immunol. 2021 Sep 28;12:740708. doi: 10.3389/fimmu.2021.740708. eCollection 2021.
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 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.
SARS-CoV-2 mRNA 疫苗已显示出高效力和免疫原性，但目前关于记忆 B 细胞产生和长期持久性的信息有限。在这里，我们研究了 145 名受试者在接受 BNT162b2 疫苗（Comirnaty）接种后长达 6 个月时的刺突特异性记忆 B 细胞和体液反应。在第二剂后 7 天，刺突特异性抗体达到峰值，并且在 6 个月后仍观察到显著的抗体滴度和 ACE2/RBD 结合抑制活性，尽管随着时间的推移逐渐下降。随着抗体减少，疫苗接种者血液中的刺突特异性记忆 B 细胞（主要是 IgG 类别转换）增加，并在接种后 6 个月持续存在。在再刺激后，循环记忆 B 细胞被激活并产生刺突特异性抗体。在加强后 7 天通过计算分析鉴定的高频率的刺突特异性 IgG 浆母细胞与 6 个月时 IgG 记忆 B 细胞的产生呈正相关。这些数据表明，mRNA BNT162b2 疫苗引发了强烈的 B 细胞免疫，具有刺突特异性记忆 B 细胞，在接种后 6 个月仍持续存在，在快速应对 SARS-CoV-2 病毒感染方面发挥着至关重要的作用。
