Memory B cells persist for a lifetime and rapidly differentiate into antibody-producing plasmablasts and plasma cells upon antigen re-encounter. The clonal relationship and evolution of memory B cells and circulating plasmablasts is not well understood. Using single-cell sequencing combined with isolation of specific antibodies, we found that in two healthy donors, the memory B cell repertoire was dominated by large IgM, IgA and IgG2 clonal families, whereas IgG1 families, including those specific for recall antigens, were of small size. Analysis of multiyear samples demonstrated stability of memory B cell clonal families and revealed that a large fraction of recently generated plasmablasts was derived from long-term memory B cell families and was found recurrently. Collectively, this study provides a systematic description of the structure, stability and dynamics of the human memory B cell pool and suggests that memory B cells may be active at any time point in the generation of plasmablasts.

记忆 B 细胞终生存在，并在再次遇到抗原时迅速分化为产生抗体的浆母细胞和浆细胞。记忆 B 细胞和循环浆母细胞的克隆关系和进化尚不清楚。使用单细胞测序结合特异性抗体的分离，我们发现在两名健康供体中，记忆 B 细胞库由大型 IgM、IgA 和 IgG2 克隆家族主导，而 IgG1 家族，包括那些对回忆抗原具有特异性的家族，是小尺寸。对多年样本的分析证明了记忆 B 细胞克隆家族的稳定性，并表明最近产生的浆母细胞中有很大一部分来自长期记忆 B 细胞家族，并且经常被发现。总的来说，这项研究提供了结构的系统描述，