Chronic Immune Reactions, German Rheumatism Research Centre Berlin, DRFZ, Leibniz Institute, Berlin, Germany.
Eur J Immunol. 2012 Aug;42(8):1981-8. doi: 10.1002/eji.201242540.
T-follicular helper (TFH) cells represent the subpopulation of CD4(+) T cells that provides help for antigen-specific B cells in the GC response. They are generated from naïve T cells during an immune response and are imprinted by their master transcription factor Bcl-6. It has been a long-standing question if TFH cells contribute to the CD4(+) memory pool after the GC response has been terminated. To answer this question, we sorted antigen-specific TFH and non-TFH effector cells from an ongoing GC response and transferred them into naïve mice. Without further signals via the TCR, transferred cells rapidly contracted with a small population of both TFH and non-TFH cells surviving as memory cells in peripheral lymphoid organs for at least 4 weeks in the absence of antigen. TFH cells strongly downregulated their signature genes Bcl-6, CXCR5, and PD-1 in the memory phase. Upon rechallenge with antigen they rapidly upregulated these markers again. An enhanced potential to produce IL-21, paired with higher expression of CXCR5 and lower expression of CCR7, should enable TFH memory cells to provide more efficient help for antigen-specific B cells than their non-TFH counterparts.
滤泡辅助 T（TFH）细胞是 CD4+T 细胞的亚群，为 GC 反应中抗原特异性 B 细胞提供帮助。它们在免疫反应中由初始 T 细胞产生，并由其主转录因子 Bcl-6 印记。长期以来，人们一直想知道 TFH 细胞是否会在 GC 反应终止后为 CD4+记忆池做出贡献。为了回答这个问题，我们从正在进行的 GC 反应中分离出抗原特异性 TFH 和非 TFH 效应细胞，并将其转移到初始小鼠中。在没有 TCR 进一步信号的情况下，转移的细胞迅速收缩，一小部分 TFH 和非 TFH 细胞作为记忆细胞存活于外周淋巴器官中，在没有抗原的情况下至少持续 4 周。TFH 细胞在记忆阶段强烈地下调其特征基因 Bcl-6、CXCR5 和 PD-1。在再次受到抗原刺激时，它们迅速再次上调这些标志物。IL-21 产生的潜力增强，与 CXCR5 表达升高和 CCR7 表达降低相结合，应使 TFH 记忆细胞能够为抗原特异性 B 细胞提供比非 TFH 细胞更有效的帮助。
