Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
Sci Immunol. 2018 Jul 20;3(25). doi: 10.1126/sciimmunol.aas9103.
CD4 T cell responses are composed of heterogeneous T cell receptor (TCR) signals that influence the acquisition of effector and memory characteristics. We sought to define early TCR-dependent activation events that control T cell differentiation. A polyclonal panel of TCRs specific for the same viral antigen demonstrated substantial variability in TCR signal strength, expression of CD25, and activation of nuclear factor of activated T cells and nuclear factor κB. After viral infection, strong TCR signals corresponded to T helper cell (T1) differentiation, whereas T follicular helper cell and memory T cell differentiation were most efficient when TCR signals were comparatively lower. We observed substantial heterogeneity in TCR-dependent CD25 expression in vivo, and the vast majority of CD4 memory T cells were derived from CD25 effector cells that displayed decreased TCR signaling in vivo. Nevertheless, memory T cells derived from either CD25 or CD25 effector cells responded vigorously to rechallenge, indicating that, although early clonal differences in CD25 expression predicted memory T cell numbers, they did not predict memory T cell function on a per cell basis. Gene transcription analysis demonstrated expression clustering based on CD25 expression and enrichment of transcripts associated with enhanced T follicular helper cell and memory development within CD25 effector cells. Direct enhancement of TCR signaling via knockdown of Src homology region 2 domain-containing phosphatase 1, a tyrosine phosphatase that suppresses early TCR signaling events, favored the differentiation of T1 effector and memory cells. We conclude that strong TCR signals during early T cell activation favor terminal T1 differentiation over long-term T1 and T follicular helper cell memory responses.
CD4 T 细胞反应由异质的 T 细胞受体 (TCR) 信号组成,这些信号影响效应器和记忆特征的获得。我们试图定义控制 T 细胞分化的早期 TCR 依赖性激活事件。针对相同病毒抗原的多克隆 TCR 面板显示 TCR 信号强度、CD25 表达和 T 细胞激活核因子 (NFAT) 和核因子 κB 的激活存在很大差异。病毒感染后,强 TCR 信号与辅助性 T 细胞 (T1) 分化相对应,而当 TCR 信号相对较低时,滤泡辅助性 T 细胞和记忆 T 细胞分化效率最高。我们观察到体内 TCR 依赖性 CD25 表达存在很大异质性,绝大多数 CD4 记忆 T 细胞来自体内 TCR 信号降低的 CD25 效应细胞。然而,来自 CD25 或 CD25 效应细胞的记忆 T 细胞对再挑战均有强烈反应,表明尽管 CD25 表达的早期克隆差异预测了记忆 T 细胞数量,但它们并未预测基于单个细胞的记忆 T 细胞功能。基因转录分析表明,基于 CD25 表达的表达聚类以及与增强的滤泡辅助性 T 细胞和记忆细胞发育相关的转录本的富集,在 CD25 效应细胞内。通过 Src 同源结构域 2 区磷酸酶 1 (SHP-1) 的基因敲低直接增强 TCR 信号,该磷酸酶可抑制早期 TCR 信号事件,有利于 T1 效应和记忆细胞的分化。我们得出结论,早期 T 细胞激活过程中的强 TCR 信号有利于 T1 终末分化,而不是长期的 T1 和滤泡辅助性 T 细胞记忆反应。