CD4+ memory T cells play an important role in protective immunity and are a key target in vaccine development. Many studies have focused on T central memory (Tcm) cells, whereas the existence and functional significance of long-lived T follicular helper (Tfh) cells are controversial. Here, we show that Tfh cells are highly susceptible to NAD-induced cell death (NICD) during isolation from tissues, leading to their underrepresentation in prior studies. NICD blockade reveals the persistence of abundant Tfh cells with high expression of hallmark Tfh markers to at least 400 days after infection, by which time Tcm cells are no longer found. Using single-cell RNA-seq, we demonstrate that long-lived Tfh cells are transcriptionally distinct from Tcm cells, maintain stemness and self-renewal gene expression, and, in contrast to Tcm cells, are multipotent after recall. At the protein level, we show that folate receptor 4 (FR4) robustly discriminates long-lived Tfh cells from Tcm cells. Unexpectedly, long-lived Tfh cells concurrently express a distinct glycolytic signature similar to trained immune cells, including elevated expression of mTOR-, HIF-1-, and cAMP-regulated genes. Late disruption of glycolysis/ICOS signaling leads to Tfh cell depletion concomitant with decreased splenic plasma cells and circulating antibody titers, demonstrating both unique homeostatic regulation of Tfh and their sustained function during the memory phase of the immune response. These results highlight the metabolic heterogeneity underlying distinct long-lived T cell subsets and establish Tfh cells as an attractive target for the induction of durable adaptive immunity.

中文翻译：

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长寿的T卵泡辅助细胞保留可塑性，并帮助维持体液免疫。

CD4 +记忆T细胞在保护性免疫中起重要作用，并且是疫苗开发中的关键目标。许多研究集中在T中央记忆（Tcm）细胞上，而长寿T卵泡辅助细胞（Tfh）的存在和功能意义尚存争议。在这里，我们显示Tfh细胞在与组织隔离的过程中极易受NAD诱导的细胞死亡（NICD）的影响，从而导致它们在先前研究中的代表性不足。NICD阻断显示感染后至少400天，具有标志性Tfh标志物高表达的丰富Tfh细胞的持久性，此时不再发现Tcm细胞。使用单细胞RNA-seq，我们证明了寿命长的Tfh细胞在转录上与Tcm细胞不同，可以保持干细胞和自我更新的基因表达，并且与Tcm细胞相比，召回后是多能的。在蛋白质水平上，我们表明叶酸受体4（FR4）可以从Tcm细胞中强有力地区分长寿命的Tfh细胞。出乎意料的是，长寿命的Tfh细胞同时表达与训练的免疫细胞相似的独特糖酵解特征，包括mTOR-，HIF-1和cAMP调控基因的表达升高。糖酵解/ ICOS信号的晚期破坏导致Tfh细胞耗竭，同时脾细胞浆细胞减少和循环抗体滴度降低，证明了Tfh的独特稳态调节及其在免疫反应记忆阶段的持续功能。这些结果突出了不同的长寿命T细胞亚群背后的代谢异质性，并将Tfh细胞确立为诱导持久适应性免疫的诱人靶标。我们表明，叶酸受体4（FR4）可以从Tcm细胞中强有力地区分长寿命的Tfh细胞。出乎意料的是，长寿命的Tfh细胞同时表达与训练的免疫细胞相似的独特糖酵解特征，包括mTOR-，HIF-1和cAMP调控基因的表达升高。糖酵解/ ICOS信号的晚期破坏导致Tfh细胞耗竭，同时脾细胞浆细胞减少和循环抗体滴度降低，证明了Tfh的独特稳态调节及其在免疫反应记忆阶段的持续功能。这些结果突出了不同的长寿命T细胞亚群背后的代谢异质性，并将Tfh细胞确立为诱导持久适应性免疫的诱人靶标。我们表明，叶酸受体4（FR4）可以从Tcm细胞中强有力地区分长寿命的Tfh细胞。出乎意料的是，长寿命的Tfh细胞同时表达与训练的免疫细胞相似的独特糖酵解特征，包括mTOR-，HIF-1和cAMP调控基因的表达升高。糖酵解/ ICOS信号的晚期破坏导致Tfh细胞耗竭，同时脾细胞浆细胞减少和循环抗体滴度降低，证明了Tfh的独特稳态调节及其在免疫反应记忆阶段的持续功能。这些结果突出了不同的长寿命T细胞亚群背后的代谢异质性，并将Tfh细胞确立为诱导持久适应性免疫的诱人靶标。