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.

中文翻译：

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T滤泡辅助细胞可以作为长期记忆细胞存活。

T卵泡辅助细胞（TFH）代表CD4（+）T细胞的亚群，可为GC反应中的抗原特异性B细胞提供帮助。它们是在免疫反应期间从幼稚T细胞产生的，并被其主转录因子Bcl-6所印记。在GC响应终止后，TFH细胞是否有助于CD4（+）记忆池是一个长期存在的问题。为了回答这个问题，我们从正在进行的GC反应中分选了抗原特异性TFH和非TFH效应细胞，并将其转移到幼稚小鼠中。在没有通过TCR的进一步信号的情况下，转移的细胞会与少量TFH和非TFH细胞迅速收缩，在没有抗原的情况下存活至少4周作为外周淋巴器官的记忆细胞。TFH细胞强烈下调其签名基因Bcl-6，CXCR5，和PD-1在存储阶段。用抗原挑战后，它们又迅速上调了这些标志物。产生IL-21的潜力增强，再加上CXCR5的更高表达和CCR7的更低表达，应该使TFH记忆细胞能够比其非TFH对应物为抗原特异性B细胞提供更有效的帮助。