Chemo-immunotherapy of methylchoranthrene-induced fibrosarcoma by concanavalin A-bound tumor vaccine, levamisole and mitomycin C.

Concanavalin A (ConA)-bound-tumor cell vaccine of methylchoranthrene-induced fibrosarcoma (Meth 1) induced tumor-specific immunoprophylactic and immunotherapeutic response against an inoculum of live Meth 1 cells in histocompatible animals. ConA-free Meth 1 vaccine induced much less response under the identical experimental conditions. Immunotherapeutic potency of ConA-bound Meth 1 vaccine was enhanced by levamisole, and 37% of the animals inoculated with 10(4) live Meth 1 cells at day 0 were cured when they were administered 10(6) cells of ConA-bound Meth 1 vaccine at days 1 and 8 and 0.63 mg/kg levamisole at days 1,2 and 3. Delayed administration of levamisole at day 8,9 and 10 was less effective than the earlier administration, but still produced a 17% cure of Meth 1-bearing animals when combined with ConA-bound Meth 1 vaccine. Immunotherapeutic response under these regimens was further enhanced by mitomycin C, and approximately 60% of the animals inoculated with 10(5) Meth 1 cells were cured when three agents were administered at the defined intervals. These results suggest the feasibility of the regimen in which the therapeutic response induced by immunotherapeutic agents is further enhanced by the selected chemotherapeutic agents.