Immunotherapy with a tumor-infiltrating lymphocyte clone, soluble antigen, and cyclophosphamide

H. Komichi, S. Smith and B. D. Kahan
Department of Surgery, University of Texas Medical School at Houston 77030.

A tumor-specific cytotoxic T-lymphocyte clone derived from bulk cultures of tumor-infiltrating lymphocytes attenuated the outgrowth of methylcholanthrene (MCA)-induced fibrosarcomas in C3H/HeJ mice. In 4-hour chromium 51-release assays, bulk cultures of tumor-infiltrating lymphocytes showed nonspecificity for MCA-induced tumors (MCA-F, MCA-D, MCA-SP), YAC-1, and EL-4. In contrast, a cytotoxic T-lymphocyte-cloned line specifically killed MCA-F, but not MCA-D or MCA-SP. Cytotoxic T-lymphocyte line 8 protected syngeneic hosts in local and systemic adoptive transfer assays. Hosts bearing 4-day-established MCA-F tumor cells received single agents or combinations of isoelectrophoretically purified butyl alcohol-extracted tumor-specific transplantation antigen (1 microgram/wk), cyclophosphamide (20 mg/kg on days 4 and 11), and/or cytotoxic T-lymphocytes (1 x 10(7) cells on days 7 and 14). While the mean tumor diameter was 11.6 +/- 1.3 mm in untreated hosts or after single treatments, the combination of tumor-specific transplantation antigen and cyclophosphamide along with the cytotoxic T-lymphocyte clone resulted in tumor diameters of 1.8 +/- 0.5 mm. The triple combination prolonged host survival from 39.6 +/- 1.6 to 57.2 +/- 4.7 days compared with antigen and cyclophosphamide treatment.