Abstract
Immunity to infections relies on clonal expansion of CD8+ T cells, their maintenance as effector CTLs, and their selection into a memory population. These processes rely on delivery of survival signals to activated CD8+ T cells. We here reveal the mechanism by which costimulatory CD27-CD70 interactions sustain survival of CD8+ effector T cells in infected tissue. By unbiased genome-wide gene expression analysis, we identified the Il2 gene as the most prominent CD27 target gene in murine CD8+ T cells. In vitro, CD27 directed IL-2 expression and promoted clonal expansion of primed CD8+ T cells exclusively by IL-2–dependent survival signaling. In mice intranasally infected with influenza virus, Cd27–/– CD8+ effector T cells displayed reduced IL-2 production, accompanied by impaired accumulation in lymphoid organs and in the lungs, which constitute the tissue effector site. Reconstitution of Cd27–/– CD8+ T cells with the IL2 gene restored their accumulation to wild-type levels in the lungs, but it did not rescue their accumulation in lymphoid organs. Competition experiments showed that the IL-2 produced under the control of CD27 supported effector CD8+ T cell survival in the lungs in an autocrine manner. We conclude that CD27 signaling directs the IL-2 production that is reportedly essential to sustain survival of virus-specific CTLs in nonlymphoid tissue.
Authors
Victor Peperzak, Yanling Xiao, Elise A.M. Veraar, Jannie Borst
Figure 3
CD27 promotes IL-2 expression in effector CD8+ T cells upon influenza virus infection.
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ISSN: 0021-9738 (print), 1558-8238 (online)