COMBINED USE OF ANTI-LYMPHOCYTE SERUM AND CYCLOPHOSPHAMIDE TO SUPPRESS RENAL-ALLOGRAFT REJECTION IN THE RAT

Abstract

Cyclophosphamide and anti-lymphocyte serum (ALS) were compared for their ability to suppress renal allograft rejection in the rat. These 2 agents were chosen since they generally act on different arms of the immune response, and might therefore complement each other''s action. Dose response studies showed that both agents could suppress rejection completely. There were no differences in their ability to suppress the lymphocytotoxic antibody [Ab] response to the graft and the histological patterns of rejection were similar. There was no evidence that cyclophosphamide was more effective in suppressing vascular lesions. The doses of both agents which suppressed the lymphocytotoxic Ab response were substantially lower than those required to suppress graft rejection. When suboptimal doses of the 2 agents were administered together, the combinations were additive and not synergistic.