Bailey, Jennifer C.Iyer, Abhirami K.Renukaradhya, Gourapura J.Lin, YinlingNguyen, HoaBrutkiewicz, Randy R.2016-11-222016-11-222014-12Bailey, J. C., Iyer, A. K., Renukaradhya, G. J., Lin, Y., Nguyen, H., & Brutkiewicz, R. R. (2014). Inhibition of CD1d-mediated antigen presentation by the transforming growth factor-β/Smad signalling pathway. Immunology, 143(4), 679–691. http://doi.org/10.1111/imm.123531365-2567https://hdl.handle.net/1805/11491CD1d-mediated lipid antigen presentation activates a subset of innate immune lymphocytes called invariant natural killer T (NKT) cells that, by virtue of their potent cytokine production, bridge the innate and adaptive immune systems. Transforming growth factor (TGF-β) is a known immune modulator that can activate the mitogen-activated protein kinase p38; we have previously shown that p38 is a negative regulator of CD1d-mediated antigen presentation. Several studies implicate a role for TGF-β in the activation of p38. Therefore, we hypothesized that TGF-β would impair antigen presentation by CD1d. Indeed, a dose-dependent decrease in CD1d-mediated antigen presentation and impairment of lipid antigen processing was observed in response to TGF-β treatment. However, it was found that this inhibition was not through p38 activation. Instead, Smads 2, 3 and 4, downstream elements of the TGF-β canonical signalling pathway, contributed to the observed effects. In marked contrast to that observed with CD1d, TGF-β was found to enhance MHC class II-mediated antigen presentation. Overall, these results suggest that the canonical TGF-β/Smad pathway negatively regulates an important arm of the host's innate immune responses - CD1d-mediated lipid antigen presentation to NKT cells.en-USPublisher PolicyAntigen PresentationimmunologyAntigens, CD1dmetabolismSignal TransductionSmad ProteinsTransforming Growth Factor betaArticle