ANTITUMOR EFFECTS OF POLYVALENT AND MONOVALENT VACCINES COUPLED WITH INTERLEUKIN-2 IN A METASTATIC MELANOMA MODEL

We have previously reported that preimmunization of mice with formalin ized extracellular antigens (fECA) derived from melanoma cells, in com bination with interleukin 2 (IL-2) treatment and surgical resection, d ecreased subsequent tumor growth and increased survival of mice in a n ew model for spontaneous metastasis of melanoma. In this study, we hav e modified the sequence of tumor growth and therapy to more closely mi mic the clinical situation. Mice were challenged subcutaneously in the tail with 5 x 10(5) B16 F10 melanoma cells and, by day 21, all of the m had developed localized melanoma tumors. The primary tumor-bearing t ails of control and experimental animals were then resected distal to the base of the tail, and therapy of the mice was initiated the follow ing day. Groups of mice received different polyvalent and monovalent m urine melanoma vaccines (including native or formalin treated extracel lular antigens, intact melanoma cells, or purified B700 antigen), with or without concomitant low doses of IL-2. The results demonstrate tha t the vaccine therapies elicited significant increases in survival of the mice, accompanied by reductions in the size of lymph nodes and in the number of pulmonary metastases. These effects, particularly with t he intact melanoma cell vaccine, could be improved even further with c oncomitant IL-2 treatment.