Berg Rance E, Cordes Christoph J, Forman James
Center for Immunology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, NA2.200, Dallas, TX 75390-9093, USA.
Eur J Immunol. 2002 Oct;32(10):2807-16. doi: 10.1002/1521-4141(2002010)32:10<2807::AID-IMMU2807>3.0.CO;2-0.
The role of CD8+ T cells in adaptive immunity is well documented and involves numerous effector mechanisms including direct cytolysis of targets and secretion of cytokines. The role of CD8+ T cells in innate immunity has not been previously appreciated. Using J774 macrophages infected in vitro with the intracellular bacterium, Listeria monocytogenes (LM), we show that CD8+ T cells isolated from naïve C57BL/6 (B6) mice respond rapidly by secreting IFN-gamma. CD8+ T cells secreting IFN-gamma can also be found in naïve B6 mice 16 h after infection with LM. This rapid IFN-gamma response is TCR-independent and mediated through the actions of IL-12 and IL-18. Cell surface staining and cell sorting experiments indicate that these novel CD8+ T cells express memory markers. In vitro CFSE-labeling experiments show that IFN-gamma-secreting CD8+ T cells proliferate rapidly after 2 days in culture and after 4 days constitute the majority of the CD8+ T cell population. Together, these data suggest an important role for IFN-gamma-secreting CD8+ T cells in the innate response to bacterial pathogens.
CD8 + T细胞在适应性免疫中的作用已有充分记载，涉及多种效应机制，包括对靶标的直接细胞溶解和细胞因子的分泌。CD8 + T细胞在固有免疫中的作用此前尚未得到重视。利用体外被细胞内细菌单核细胞增生李斯特菌（LM）感染的J774巨噬细胞，我们发现从未经免疫的C57BL / 6（B6）小鼠中分离出的CD8 + T细胞通过分泌γ干扰素迅速做出反应。在感染LM 16小时后的未经免疫的B6小鼠中也能发现分泌γ干扰素的CD8 + T细胞。这种快速的γ干扰素反应不依赖TCR，而是通过IL - 12和IL - 18的作用介导的。细胞表面染色和细胞分选实验表明，这些新型CD8 + T细胞表达记忆标志物。体外CFSE标记实验表明，分泌γ干扰素的CD8 + T细胞在培养2天后迅速增殖，4天后构成CD8 + T细胞群体的大多数。总之，这些数据表明分泌γ干扰素的CD8 + T细胞在对细菌病原体的固有反应中发挥重要作用。
