The JES5-2A5 antibody is specific for mouse IL-10. IL-10 has numerous biological activities including the ability to inhibit both the synthesis of Th1 cytokines and proliferation of T cells. In the mouse, IL-10 is produced by phagocytic cells, conventional dendritic, cells, T cells, B cells, and NK cells. The JES5-2A5 antibody is a neutralizing antibody.