The antibody reacts with human Interleukin-10 (IL-10) of both natural and recombinant origin. IL-10 is a pluripotent cytokine with important immunosuppressive actions: it can inhibit cytokines involved in the Th1 response such as IL-2, Interferon gamma and also inhibits the production of pro-inflammatory cytokines such as IL-1, IL-6, IL-8 and TNF-alpha. The antibody inhibits the biological activity of natural and recombinant human IL-10. The antigen specificity was further assessed by ELISA. No cross reactivities with other cytokines have been detected.