[Subrenal capsule assay in normal mice immunosuppressed by cyclosporin A].

The subrenal capsule assay in normal mice has more advantages to evaluate sensitivities of anticancer agents than other assays in vivo. However, this method has difficulties because mice reject human tumor grafts by their immune reaction. We examined three methods of immunosuppression in mice; radiation, administration of cyclophosphamide and that of cyclosporin A. The administration of cyclosporin A suppressed host reactions most effectively among the three, and the human tumor grafts in subrenal capsules grew well. We also investigated the intervals of administration and the doses of cyclosporin A in order to evaluate drug response. The minimal dose of cyclosporin A which inhibited host reactions was revealed to be 50mg/kg/day administered subcutaneously to mice. Then the adequate dosage of each anticancer drug for this assay system was investigated so that the body weights of mice do not decrease more than 20%, and the following doses were determined; Mitomycin C: 5mg/kg; Cisplatinum: 4mg/kg; Cyclophosphamide: 100mg/kg and 5FU: 90 mg/kg.