Gene expression profiles of human effector CD8+ T cell subsets. Homo sapiens

Effector CD8+ T cells are believed to be terminally differentiated cells having cytotoxic activity and the ability to produce effector cytokines such as INF-γ and TNF-α. We investigated the difference between CXCR1+ and CXCR1- subsets of human effector CD27-CD28-CD8+ T cells. Both subsets similarly expressed cytolytic molecules and exerted substantial cytolytic activity, whereas only the CXCR1- subset had IL-2 productivity and self-proliferative activity and was more resistant to cell death than the CXCR1+ subset. These differences were explained by the specific up-regulation of CAMK4, SPRY2, and IL-7R in the CXCR1- subset and that of pro-apoptotic DAPK1 in the CXCR1+ subset. The IL-2 producers were more frequently found in the IL-7R+ subset of the CXCR1- effector CD8+ T cells than in the IL-7R- subset. IL-7/IL-7R signaling promoted cell survival only in the CXCR1- subset. The present study has highlighted a novel subset of effector CD8+ T cells producing IL-2 and suggests the importance of this subset in the homeostasis of effector CD8+ T cells. Overall design: To find the genes that potentially cause the difference in IL-2 productivity and cell survival between the CXCR1+ and CXCR1- human effector CD8+ T cell subsets, we performed microarray gene expression analysis. We highly purified each CD3+CD8+ subset for this analysis (> 95.3%) from 5 healthy individuals, and then compared the gene expression profiles of each subset.