Combined treatment of autoimmune MRL/Mp-lpr/lpr mice with cholera toxin plus irradiation

MRL/Mp-lpr/lpr (MRL/1) mice spontaneously develop autoimmune diseases like systemic lupus erythematosus (SLE) from 2 months of age, accompanied by massive lymphadenopathy. Such mice of 2 months of age were treated with 1g cholera toxin (CT) every 7 days and/or with 400 rad of one-shot⁶⁰Co irradiation. CT treatment alone markedly improved nephritis as evaluated by proteinuria and moderately suppressed lymphadenopathy and anti-DNA antibody production, while irradiation alone prominently improved lymphadenopathy but showed little effect on both nephritis and anti-DNA antibody production. On the other hand, when mice were treated with the combination of CT plus irradiation, autoimmune nephritis as well as anti-DNA production and lymphadenopathy were almost completely inhibited. Taken together, each agent exerts the improvement effect at the different points from each other in an abnormal immunological circuit displayed in MRL/1 mice. This kind of combined treatment may be applicable to the clinical use for autoimmune diseases.