INTERLEUKIN-2 THERAPY OF LYMPHOMA-BEARING IMMUNOSUPPRESSED MICE

In the present study, the immune status of syngeneic Balb/c animals be aring a poorly metastatic RAW117-P lymphoma and the highly malignant l iver metastatic variant RAW117-H10 lymphoma were measured and compared to control animals with no known tumor. The immune status was evaluat ed by performing various analyses of spleen cells for the frequencies of immune cells using flow cytometry, in vitro mitogen response and in vitro NK cell-mediated cytotoxicity assays on days 6, 9 and 12 after tumor transplantation. The results of these studies indicated that fro m day 9 onwards, some of the immune response of the RAW117 lymphoma-be aring animals appeared to decrease compared to control animals. In ord er to boost the immune response of the tumor-bearing immunosuppressed animals, recombinant interleukin-2 (rIL-2) was administered to RAW117- H10 lymphoma-bearing animals. The immune status of tumor-bearing anima ls treated with rIL-2 was evaluated on days 5, 10 and 15 after tumor t ransplantation using similar analyses of spleen cells as described abo ve. The results of these experiments indicated that 11,-2 treatment in creased splenic levels of cytotoxic cells, and decreased the in vivo t umorigenicity/metastasis of metastatic RAW117-H10 lymphoma cells. rIL- 2 administration resulted in a significant increase in survival of tum or-bearing animals, and histological studies showed significantly lowe r tumor burdens in treated animals: it appears that rIL-2 has a benefi cial therapeutic effect on immunosuppressive metastatic RAW117 lymphom a.