The immunosuppressive activity of adamantoyl cytarabine. 3. Immunosuppressive specificity in rats.

The immunosuppressive specificity of adamantoyl cytarabine [1-β-D-arabinofuranosylcytosine 5′-(1-adamantanecarboxylate), ADOCA] has been studied in rats. Previously, ADOCA had been shown to prolong skin allograft survival in both rats and mice, and to suppress the graft--host reaction and haemagglutinin response of mice. In the current experiments, although ADOCA was capable of markedly suppressing the response of rats to bovine serum albumin, ADOCA could not suppress the primary haemagglutinin response to sheep erythrocytes, nor the agglutinin response to bacterial flagellin. In comparing ADOCA with other immunosuppressants, with one possible exception, ADOCA appears to possess unique immunosuppressive specificity in rats. The major site of ADOCA immunosuppression in the rat was suggested to be the thymus-dependent bone marrow-derived lymphocyte.