Spleen cell factor inhibits lymphoproliferation, abnormal Ia expression and overt autoimmunity in MRL-lpr mice.

Autoimmune MRL-lpr have an abnormal pattern of lymphokine production. In our attempt to repair this defect, MRL-lpr mice were prophylactically treated daily with a lectin stimulated rat spleen cell product rich in interleukin-2. Therapy inhibited the lymphoid hyperplasia of the unique lymphocytes regulated by the lpr gene, suppressed the enhanced supranormal expression of Ia on peritoneal macrophages and protected this strain from autoimmune renal injury. Purified recombinant interleukin-2 alone did not prevent autoimmune disease expression. Thus, a spleen cell product other than interleukin-2 can ameliorate the aggressive course of lymphoproliferation and autoimmunity in MRL-lpr mice.