Requirement for Stat4 in interleukin-12-mediated responses of natural killer and T cells

Abstract

SIGNAL transducers and activators of transcription (STATs) are activated by tyrosine phosphorylation in response to cytokines and mediate many of their functional responses. Stat4 was initially cloned as a result of its homology with Stat1 (refs 4, 5) and is widely expressed, although it is only tyrosine-phosphorylated after stimulation of T cells with interleukin (IL)- 12 (refs 6, 7). IL-12 is required for the T-cell-independent induction of the cytokine interferon (IFN)-γ, a key step in the initial suppression of bacterial and parasitic infections. IL-12 is also important for the development of a Th1 response, which is critical for effective host defence against intracellular pathogens. To..