Authors:
Xiaoming Feng, Haikun Wang, Hiroshi Takata, Timothy J Day, Jessica Willen, & Hui Hu
Summary:
The molecular mechanisms that underlie T cell quiescence are poorly understood. Here we report that mature naive CD8+ T cells lacking the transcription factor Foxp1 gained effector phenotype and function and proliferated directly in response to interleukin 7 (IL-7) in vitro. Foxp1 repressed expression of the IL-7 receptor α-chain (IL-7Rα) by antagonizing Foxo1 and negatively regulated signaling by the kinases MEK and Erk. Acute deletion of Foxp1 induced naive T cells to gain an effector phenotype and proliferate in lympho-replete mice. Foxp1-deficient naive CD8+ T cells proliferated even in lymphopenic mice deficient in major histocompatibility complex class I. Our results demonstrate that Foxp1 exerts essential cell-intrinsic regulation of naive T cell quiescence, providing direct evidence that lymphocyte quiescence is achieved through actively maintained mechanisms that include transcriptional regulation.
Source:
Nature Immunology; 12, 544-550 (05/01/11)