IL-36γ signaling controls the induced regulatory T cell-Th9 cell balance via NFκB activation and STAT transcription factors.

Regulatory and effector T helper (Th) cells are abundant at mucosal surfaces, especially in the intestine, where they control the critical balance between tolerance and inflammation. However, the key factors that reciprocally dictate differentiation along these specific lineages remain incompletely understood. Here we report that the interleukin-1 (IL-1) family member IL-36γ signals through IL-36 receptor, myeloid differentiation primary response gene 88, and nuclear factor-κBp50 in CD4+ T cells to potently inhibit Foxp3-expressing induced regulatory T cell (Treg) development, while concomitantly promoting the differentiation of Th9 cells via a IL-2-STAT5- (signal transducer and activator of transcription factor 5) and IL-4-STAT6-dependent pathway. Consistent with these findings, mice deficient in IL-36γ were protected from Th cell-driven intestinal inflammation and exhibited increased colonic Treg cells and diminished Th9 cells. Our findings thus reveal a fundamental contribution for the IL-36/IL-36R axis in regulating the Treg-Th9 cell balance with broad implications for Th cell-mediated disorders, such as inflammatory bowel diseases and particularly ulcerative colitis.

Alternate costimulatory molecules in T cell activation: differential mechanisms for directing the immune response.

T cells are required for an effective immune response against a wide range of pathogens and for the generation of immunological memory. T cell activation can be divided into two phases: an antigen-specific signal delivered through the T cell antigen receptor, and a costimulatory signal delivered through accessory molecules on the T cell surface. Following activation, T cells differentiate to acquire distinct effector functions depending on the costimulatory signal, cytokine environment, and the pathogen itself. Although CD28 has been identified as the dominant costimulatory molecule, several other molecules have been described as having a costimulatory function. This review will focus on recent evidence for the existence of alternate costimulatory molecules, and the differential roles they might play in the activation, development, and survival of T cells.

Triptolide is more effective in preventing T cell proliferation and interferon-gamma production than is FK506.

The Chinese traditional herb Tripterygium wilfordii Hook. F (TWHF) has been reported to be effective in the treatment of a variety of autoimmune disorders. The major active component of this herb is triptolide and most of the efficacy of this herb immunosuppression is attributed to triptolide. FK506 is also a potent immunosuppressive agent and is currently being used clinically. The present studies compare the effectiveness of triptolide and FK506 to suppress certain human T cell functions. Specifically human T cell proliferation, IL-2 and IFNgamma were compared. The results show that, overall, triptolide is more effective at inhibiting T cell proliferation and IFNgamma production than FK506 and the two compounds inhibit IL-2 production in an equivalent manner.