Cutting Edge: IL-12 inversely regulates T-bet and eomesodermin expression during pathogen-induced CD8+ T cell differentiation.

Abramson Family Cancer Research Institute and Department of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA.
The Journal of Immunology (Impact Factor: 5.36). 01/2007; 177(11):7515-9. DOI: 10.4049/jimmunol.177.11.7515
Source: PubMed

ABSTRACT Cytokines are critical determinants for specification of lineage-defining transcription factors of CD4+ T cell subsets. Little is known, however, about how cytokines regulate expression of T-bet and eomesodermin (Eomes) in effector and memory CD8+ T cells. We now report that IL-12, a signature of cell-mediated immunity, represses Eomes while positively regulating T-bet in effector CD8+ T cells during infection with Listeria monocytogenes. After resolution of infection and abatement of IL-12 signaling, Eomes expression rises whereas T-bet expression declines in memory CD8+ T cells. Eomes becomes derepressed in effector cells by ablation of IL-12 signaling. In the absence of IL-12, the dynamics of clonal expansion and contraction are also perturbed. Together, these results reveal how a pathogen-associated signal, such as IL-12, could act as a switch, regulating appropriate clonal growth and decline while, in parallel, shaping a unique pattern of fate-determining transcription factors.

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