UNASSIGNED: Measurement of specific plasma IgG antibodies was combined with functional analyses of antibody-secreting plasmablasts and Bmems. SARS-CoV-2- and HCoV-specific IgG antibodies were quantified with an in-house bead-based multiplexed immunoassay.
UNASSIGNED: The antibody and B cell responses to COVID-19 vaccination reflected the kinetics of a prime-boost immunization, characterized by a slow and moderate primary response and a faster and stronger secondary response. In contrast, the influenza vaccinees possessed robust immune memory for the vaccine antigens prior to vaccination, and the recall vaccination moderately boosted antibody production and Bmem responses. Antibody levels and Bmem responses waned several months after the 2nd COVID-19 vaccination, but were restored upon the 3rd vaccination. The COVID-19 vaccine-induced antibodies mainly targeted novel, non-cross-reactive S1 epitopes of the viral spike protein, while cross-reactive S2 epitopes were less immunogenic. Booster vaccination not only strongly enhanced neutralizing antibodies against an original SARS-CoV-2 strain, but also induced neutralizing antibodies against the Omicron BA.2 variant. We observed a 100% plasma antibody prevalence against the S1 subunits of HCoVs, which was not affected by vaccination.
UNASSIGNED: Overall, by complementing classical serology with a functional evaluation of plasmablasts and memory B cells we provide new insights into the specificity of COVID-19 vaccine-induced antibody and B cell responses.
■特异性血浆IgG抗体的测量与分泌抗体的成浆细胞和Bmems的功能分析相结合。SARS-CoV-2和HCoV特异性IgG抗体用内部基于珠子的多重免疫测定法定量。
对COVID-19疫苗接种的抗体和B细胞反应反映了初次加强免疫的动力学,以缓慢和中等的初级反应和更快和更强的次级反应为特征。相比之下,流感疫苗接种前对疫苗抗原具有强大的免疫记忆,召回疫苗适度地增强了抗体产生和Bmem反应。第二次COVID-19疫苗接种后几个月,抗体水平和Bmem反应减弱,但在第三次接种疫苗后恢复。COVID-19疫苗诱导的抗体主要靶向新型,病毒刺突蛋白的非交叉反应S1表位,而交叉反应的S2表位免疫原性较低。加强疫苗接种不仅强烈增强了针对原始SARS-CoV-2菌株的中和抗体,而且还诱导了针对OmicronBA.2变体的中和抗体。我们观察到针对HCoVS1亚基的100%血浆抗体患病率,不受疫苗接种的影响。
■总的来说,通过对成浆细胞和记忆B细胞的功能评估来补充经典血清学,我们为COVID-19疫苗诱导的抗体和B细胞反应的特异性提供了新的见解。