부산대학교 도서관

T cell quiescence is essential for maintaining a broad repertoire against a large pool of diverse antigens from microbes and tumors, but the underlying molecular mechanisms remain largely unknown. We show here that CD8a is critical for the maintenance of CD8+ T cells in a physiologically quiescent state in peripheral lymphoid organs. Upon inducible deletion of CD8a, both naïve and memory CD8+ T cells spontaneously acquired activation phenotypes and subsequently died without exposure to specific antigens. PILRa was identified as a ligand for CD8a in both mice and humans, and disruption of this interaction was able to break CD8+ T cell quiescence. Thus, peripheral T cell pool size is actively maintained by the CD8a-PILRa interaction in the absence of antigen exposure. [ABSTRACT FROM AUTHOR]