Description: Mouse IL-10 is an ~18 kDa cytokine, also known as Cytokine Synthesis Inhibitory Factor (CSIF). In the mouse, Th2 cells, B1 cells and keratinocytes are the major cell subsets that produce IL-10. IL-10 inhibits synthesis of Th1 cytokines and proliferation of T cells, and acts as a costimulatory signal for mast cells, developing thymocytes and the Th2 response.