The roles of innate T cells in bacterial infection

先天T细胞被定义为(1)在胸腺中以不同于传统T细胞的信号通路发育的细胞，(2)表达激活和/或记忆T细胞表型并表现出即时效应功能的细胞。(3)细胞，包括y6 T细胞，记忆表型（MP） CD44^<高> CD62L^<低> CD4^+和CD8^+ T细胞。先天的y6t细胞已经在胎儿胸腺内分化为产生白细胞介素(IL)-li的细胞。HESl在胸腺中调节产生IL-li的y6 T细胞的分化，“天然存在的y6 T细胞”在全身感染牛分枝杆菌卡介苗后的很早期就在肺中发挥保护作用。我们进一步发现，IL-lsKo小鼠对单核增生李斯特菌高度敏感，在缺乏IL-Is的情况下，单核增生李斯特菌诱导的先天性CD8^+ T细胞的旁观者增殖受到损害。这些结果提示IL-Is在先天CD8 + T细胞的维持和功能中发挥重要作用，参与先天宿主防御机制。我们还发现CDsoLKO小鼠对单核细胞增生乳杆菌感染高度敏感，感染后早期先天MP IFN-y+ CD4+ T细胞显著减少。这些发现提示CDsoL在细菌感染后早期激活先天CD4^+ T细胞的潜在作用。

Innate T cells are defined as(1) cells that develop in the thymus under different signal pathways from conventional T cells,(2) cells that express an activated and/or memory T-cell phenotype and exhibit immediate effector functions.(3) cells that includd y6 T cells, memory phenotype(MP) CD44^<hlgh> CD62L^<low> CD4^+ and CD8^+ T cells. Innate y6 T cells already differentiate into interleukin(IL)-li-producing cells within the fetal thymus. HESl plays a role in regulating differentiation of IL-li producing y6 T cells in thymus and" naturally occurring y6 T cells" play a protective role in the lung at very early stage after systemic infection with Mycobacterium bovis BCG. We further found that IL-lsKo mice are highly susceptible to Listeria monocytogenes and bystander proliferation of the innate CD8^+ T cells induced by L. monocytogenes was impaired in the absence of IL-Is. These results suggested that IL-Is plays an important role in the maintenance and functions of innate CD8^+ T cells, which participate in innate host defense mechanisms. We also found that CDsoLKO mice are highly susceptible to L. monocytogenes infection accompanied by a marked decrease in innate MP IFN-y+ CD4+ T cells at an early stage after infection. These findings suggested that a potential role of CDsoL in activation of innate CD4^+ T cells at an early stage after bacterial in fection.