OX40L inhibits the generation of IL-10-producing Tr1 cells from naïve and memory CD4+ T cells induced by the immunuosuppressive drugs
dexamethasone and
vitamin D3. This unique function of OX40L is not shared by two other costimulatory TNF-family members, GITR-ligand and 4-1BB-ligand. OX40L also strongly inhibits the generation of IL-10-producing Tr1 cells induced by two physiological stimuli provided by inducible costimulatory ligand and immature DCs and inhibits the production of IL-10 by regulatory T cells. It has thus been shown that signaling the OX40-
receptor on human T cells by
monoclonal antibodies, small molecules, or OX40L regulates the generation and function of IL-10 producing immunosuppressive T cells. Also provided are high
throughput methods for identifying substances that promote or inhibit the generation and function of IL-10 producing T cells. Numerous
disease states, such as human allergic, autoimmune, and autoimmune diseases, and
cancer, may be treated by targeting OX40 / OX40L.