Effects of T-cell derived leptin on thymic function and immune regulation (85.8)

Abstract

Abstract The communication between the state of systemic and cellular energy balance to the immune compartment is mediated via a complex array of cytokines, hormones and neuropeptides. Leptin is an adipocyte-derived hormone and belongs structurally to the cytokine family including members such IL-2 and IL-12. Leptin signals via a class I cytokine receptor and represents an important link between energy balance on the one side and immune function on the other. Leptin has recently been shown to be produced in limited quantities by murine T cells. To examine the endogenous role of this hormone in the development and control of the adaptive immune responses and inflammation, we have generated T-cell transgenic mice overexpressing leptin. Leptin overexpression in T cells affects thymic size and cellularity and may have considerable impact on the immune function of aging mice. Preliminary data shows that, leptin differentially affects cytokine production by T cells, increasing IL-1, IL-6, IL-12, G-CSF, and MIP-1a levels in leptin transgenic mice compare to wild-type control. More specifically, IFN-g production was significantly higher in older leptin-TG mice, suggesting that endogenously produced leptin may play an important role in the generation of pro-inflammatory Th1 immune responses and thymic development with age.