Anti-inflammatory action of alpha-melanocyte stimulating hormone (α-MSH) in anti-CD3/CD28-mediated spleen and CD4+CD25− T cells and a partial participation of IL-10

α-Melanocyte stimulating hormone (α-MSH) has been shown to inhibit the production and the effects of pro-inflammatory cytokine by inflammatory cells in innate immunity. We have determined whether α-MSH inhibits anti-CD3/CD28-mediated spleen cells and CD4+CD25− T cells proliferation and its mechanism of action. The proliferation of anti-CD3/CD28-mediated spleen cells and CD4+CD25− T cells markedly were suppressed by 50-100 nM and 5-100 nM α-MSH, respectively. α-MSH (100 nM) increased the production of the anti-inflammatory cytokine IL-10 and decreased the production of the pro-inflammatory cytokine IL-2 and IFN-γ from CD4+CD25− T cells. Moreover, anti-IL-10 blocking Ab decreased the inhibitory effects of anti-CD3/CD28-mediated spleen cells and CD4+CD25− T cells proliferation by α-MSH, indicating a partial participation of IL-10 in its mechanism of inhibitory action. These results suggest that α-MSH may be useful for treatment of autoimmune diseases and transplantation involving innate and adaptive immunity.