Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109.
J Immunol. 2013 Dec 15;191(12):5793-6. doi: 10.4049/jimmunol.1302509. Epub 2013 Nov 13.
The number of memory phenotype CD8 T cells increases dramatically with aging in both humans and mice. However, the mechanism for this is unknown. The prevailing hypothesis is that memory T cells accumulate with aging as a result of lifelong antigenic stimulation. However, data supporting this supposition are lacking. In this study, we demonstrate that central memory CD8 T cells, which represent a large majority of memory CD8 T cells in aged mice, are not memory cells that develop in response to antigenic stimulation but are virtual memory cells that develop without antigenic stimulation. In addition to phenotypic evidence, we show that accumulation of central memory CD8 T cells is independent of CD4 T cells, CCR5, and CXCR3, all of which are known to be essential for Ag-driven development of central memory CD8 T cells. Thus, this study reveals a novel mechanism for aging-related changes in CD8 T cells.
随着年龄的增长，人类和小鼠的记忆表型 CD8 T 细胞数量都会显著增加。然而，其具体机制尚不清楚。目前普遍的假设是，记忆 T 细胞随着年龄的增长而积累，这是由于终身的抗原刺激。然而，支持这一假设的数据却很缺乏。在这项研究中，我们证明了在老年小鼠中占绝大多数的中央记忆 CD8 T 细胞并不是针对抗原刺激而产生的记忆细胞，而是在没有抗原刺激的情况下产生的虚拟记忆细胞。除了表型证据外，我们还表明中央记忆 CD8 T 细胞的积累与 CD4 T 细胞、CCR5 和 CXCR3 无关，这些都是已知的对中央记忆 CD8 T 细胞的 Ag 驱动发育至关重要的因素。因此，这项研究揭示了 CD8 T 细胞与年龄相关变化的一种新机制。
