Clinical outcome of a protocol to produce immunosuppression in rhesus monkeys (Macaca mulatta): application to infectious disease and gene therapy studies

Induced immunosuppression is required for a number of studies using rhesus monkeys (Macaca mulatta). This report describes: the clinical outcome and s afety of a dose-finding experiment that determined doses of cyclophosphamid e and prednisone that could be used to induce a state of immunosuppression in rhesus monkeys. After determining the optimum dose of immunosuppressive agents, the protocol was then used on animals participating in infectious d isease and gene therapy studies. Splenectomy was performed in some animals to increase the severity of immunosuppression. The onset, duration, and sev erity of lymphopenia and leukopenia were consistent in all animals. In most animals, physical examination findings and clinical serum chemistry profil es demonstrated only transient abnormalities. With proper clinical monitori ng, combination treatment with cyclophosphamide and prednisone is an effect ive and safe method for inducing immunosuppression in rhesus monkeys.