Immunization of mice with irradiated melanoma tumor cells transfected to secrete lymphokines and coupled with IL-2 or GM-CSF therapy.

We compared the immunogenic activity of irradiated vaccines prepared from B16 F10 melanoma cells with one made from B16 F10 melanoma cells transfected with genes encoding murine IL-2 or GM-CSF. Vaccines were studied in the conditions of treatment of C57BL/6 mice with or without the corresponding lymphokines. Control and prevaccinated mice were challenged with parental B16 F10 murine melanoma cells (5 x 10(5)) subcutaneously in the midtail to examine growth of the primary (local) tumor in the middle of the tall and metastases to the lungs. This experimental model is very close to the clinical stages of metastatic melanoma. The effectiveness of preimmunization of mice was determined by the levels of antibody production to a melanoma-associated antigen termed B700. The comparison of antibody production, growth of primary melanoma tumors, number of mice surviving at the end of the observation period, mean survival time and per cent mice with metastases in the lungs showed that the best course of immunotherapy was prevaccination of mice with a vaccine of irradiated B16 F10 melanoma cells transfected to secrete GM-CSF, coupled with GM-CSF therapy.