Specific suppression of humoral and delayed hypersensitivity responses by cyclophosphamide in an experimental model of autoimmunity.

The aim of this report is to investigate the effect of cyclophosphamide (CY) in an experimental model of autoimmunity to rat male accessory glands. The results indicated that 100 mg/kg of this drug suppressed humoral immune response that persisted for at least 45 days when administered 3 days after the first immunization of rats with modified rat male accessory glands (MRAG) in complete Freund's adjuvant (CFA). Administration of the drug 3 days before ID injection of antigen caused a shorter suppression of antibody formation. Delayed type hypersensitivity (DTH) studied 13 days after the first immunization was suppressed only in the animals that were administered CY after the antigen. The specificity of the immunosuppression was studied in rats treated with CY after the first immunization with MRAG using aggregated human gamma-globulin (AHGG) as an unrelated antigen. The studies demonstrated significant suppression of DTH (p less than 0.005) and humoral immunity only against MRAG. On the contrary, the response to AHGG was not significantly modified.