Preimmunization of mice with formalinized extracellular antigens of melanoma in combination with IL-2 and surgical resection increased survival and tumor control in metastatic melanoma model.

Recently we found that immunization with formalized extracellular antigens (FECAs) could induce the production of specific antimelanoma antibodies and increase the defense mechanisms of antimelanoma cellular and humoral immunity. In experiments we used pathogen-free female mice C57BL/6 18-20 g. We injected FECA (0.02 mg of protein/per S.C.--subcutaneous injection) for 1 month, once per week. Concurrently we injected S.C. human recombinant IL-2: 100 U/g of weight (2,000 U/per mouse). Interleukin-2 (IL-2) was injected for 1 month, 5 days/week. On days 7, 14, 21, and 28 we took retroorbital blood from mice for the study of anti-FECA and anti-IL-2 antibody production with ELISA. Control and experimental mice were then given a subcutaneous injection with 0.5 x 10(6) cells B16-F10 melanoma in 25 microliters into the middle of the tail. By 18 days 100% developed local melanoma tumors. We resected tails of all control and experimental animals 5 mm distal the base of the tail under metaphan anesthesia. The production of antibodies to FECA and IL-2 started after the 21st day and was higher in the group of mice immunized with FECA and with IL-2 than in control animals. Combining preimmunization with FECA and IL-2 and resection of local melanoma tumors decreased the mortality and the number of mice with local recurrence and metastatic melanoma tumors to the lungs.