The role of human autoantibodies against gamma-interferon.

Natural antibodies to gamma-interferon (IFN-gamma) were detected in the serum of viral infected patients and also in the serum of healthy subjects at a lower titre. The increased titres of antibodies to IFN-gamma in sera from viral infected patients, and their decrease with clinical resolution, indicates that these antibodies are related to the viral infection and probably reflect IFN-gamma production as a result of antigenic stimulation in vivo. These antibodies were affinity-purified and studied for their capability to interfere with the multiple activities of IFN-gamma in vitro. Data obtained show that human anti-IFN-gamma antibodies interfere with the immunomodulating activity but not with the antiviral and antiproliferative activity of lymphokine. Autoantibodies to IFN-gamma may have a role in the immunoregulatory process serving to limit the intensity and or duration of the immune response. Being able to interfere with the immunomodulating activities of IFN-gamma, these antibodies might open up new therapeutic possibilities for those diseases which carry evidence of activated cell-mediated immunity.