Institute of Cellular & Molecular Immunology, University Medical Center Göttingen, Göttingen, Germany.
Immunol Rev. 2018 May;283(1):150-160. doi: 10.1111/imr.12651.
The generation of memory B cells (MBCs) that have undergone immunoglobulin class switching from IgM, which dominates primary antibody responses, to other immunoglobulin isoforms is a hallmark of immune memory. Hence, humoral immunological memory is characterized by the presence of serum immunoglobulins of IgG subtypes known as the γ-globulin fraction of blood plasma proteins. These antibodies reflect the antigen experience of B lymphocytes and their repeated triggering. In fact, efficient protection against a previously encountered pathogen is critically linked to the production of pathogen-specific IgG molecules even in those cases where the primary immune response required cellular immunity, for example, T cell-mediated clearance of intracellular pathogens such as viruses. Besides IgG, also IgA and IgE can provide humoral immunity depending on the microbe's nature and infection route. The molecular mechanisms underlying the preponderance of switched immunoglobulin isotypes during memory antibody responses are a matter of active and controversial debate. Here, we summarize the phenotypic characteristics of distinct MBC subpopulations and discuss the decisive roles of different B cell antigen receptor isotypes for the functional traits of class-switched B cell populations.
记忆 B 细胞（MBC）的产生是免疫记忆的标志，这些细胞经历了免疫球蛋白类别转换，从在初次抗体反应中占主导地位的 IgM 转换为其他免疫球蛋白同型。因此，体液免疫记忆的特征是存在称为血浆蛋白 γ球蛋白部分的 IgG 亚型的血清免疫球蛋白。这些抗体反映了 B 淋巴细胞的抗原经验及其反复触发。事实上，即使在初次免疫反应需要细胞免疫的情况下，例如 T 细胞介导清除病毒等细胞内病原体，针对先前遇到的病原体的有效保护也与产生针对病原体的特异性 IgG 分子密切相关。除了 IgG，IgA 和 IgE 也可以根据微生物的性质和感染途径提供体液免疫。在记忆抗体反应中，切换免疫球蛋白同型占优势的分子机制是一个活跃和有争议的话题。在这里，我们总结了不同 MBC 亚群的表型特征，并讨论了不同 B 细胞抗原受体同型对类别转换 B 细胞群体功能特征的决定性作用。
