Mittrücker Hans-Willi, Visekruna Alexander, Huber Magdalena
Institute for Immunology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Arch Immunol Ther Exp (Warsz). 2014 Dec;62(6):449-58. doi: 10.1007/s00005-014-0293-y. Epub 2014 May 31.
It is well established that CD8(+) T cells constitute an important branch of adaptive immunity contributing to clearance of intracellular pathogens and providing long-term protection. These functions are mostly fulfilled by the best characterized subpopulation of CD8(+) T cells, the cytotoxic T lymphocytes (also called Tc1 cells), owing to their ability to kill infected cells and to secrete cytokines such as interferon-γ and tumor necrosis factor-α. However, there is growing evidence for alternative CD8(+) T cell fates influencing CD4(+) T-cell-mediated responses in the context of allergy, autoimmunity and infections. Thus, like subpopulations of CD4(+) T cells, also CD8(+) T cells under particular conditions acquire the expression of interleukin (IL)-4, IL-5, IL-9, IL-13, IL-17 or suppressive activity and thereby influence immune responses. The process of CD8(+) T-cell differentiation is dictated by antigen strength, co-stimulatory molecules and cytokines. These environmental cues induce transcription factors further specifying CD8(+) T-cell decision into Tc1, Tc2, Tc9, Tc17 or CD8(+) T regulatory fate. Here, we discuss our current understanding about functional diversity of effector CD8(+) T cells and contribution of transcription factors to this process.
众所周知，CD8(+) T细胞是适应性免疫的一个重要分支，有助于清除细胞内病原体并提供长期保护。这些功能主要由特征最明确的CD8(+) T细胞亚群——细胞毒性T淋巴细胞（也称为Tc1细胞）来实现，这是因为它们具有杀死被感染细胞以及分泌细胞因子（如干扰素-γ和肿瘤坏死因子-α）的能力。然而，越来越多的证据表明，在过敏、自身免疫和感染的背景下，替代性CD8(+) T细胞命运会影响CD4(+) T细胞介导的反应。因此，与CD4(+) T细胞亚群一样，CD8(+) T细胞在特定条件下也会获得白细胞介素（IL）-4、IL-5、IL-9、IL-13、IL-17的表达或抑制活性，从而影响免疫反应。CD8(+) T细胞的分化过程由抗原强度、共刺激分子和细胞因子决定。这些环境信号诱导转录因子，进一步将CD8(+) T细胞的分化导向Tc1、Tc2、Tc9、Tc17或CD8(+) T调节性细胞命运。在此，我们讨论目前对效应性CD8(+) T细胞功能多样性以及转录因子在此过程中的作用的理解。
