Comparative Study of Chemotherapy and/or Immunotherapy of Established Experimental Brain Tumors

Intracerebral injection of 5×105 nitrosourea-induced glioma cells (T9 tissue culture line) consistently produced brain tumors in syngenic Cesarean Derived Fisher rats. The tumors were 1 mm in diameter within 7 days and caused death within 23 days (mean results). The effects of therapy with ACNU and/or Corynebacterium parvum (C. parvum) were evaluated. C. parvum alone was apparently ineffective. ACNU (10 mg/kg body weight) given on days 7 and 14 prolonged the mean survival time to 33.4 days. Combined treatment with ACNU and intradermal immunization with T9 cells and C. parvum on days 7 and 14, or on days 0 and 7, prolonged the mean survival time to 35.3 and 39.6 days, respectively. Eleven rats that survived following this treatment showed specific immunity against T9 cells, as demonstrated by subsequent challenge with T9 cells. The Winn's test procedure showed that spleen lymphocytes from immune rats were effective against T9 cells. The results suggest that immunochemotherapy may be an effective treatment for rats with established brain tumors.