A novel proteoliposomal vaccine elicits potent antitumor immunity in mice

Therapeutic vaccination against idiotype is a promising strategy for immunotherapy of B-cell malignancies. Its feasibility, however, is limited by the requirement for a patient-specific product. Here we describe a novel vaccine formulation prepared by simply extracting cell-membrane proteins from lymphoma cells and incorporating them together with IL-2 into proteoliposomes. The vaccine was produced in 24 hours, compared with more labor-intensive and time-consuming hybridoma or recombinant DNA methods. The vaccine elicited T-cell immunity in vivo, as demonstrated by secretion of type 1 cytokines. It protected against tumor challenge at doses of tumor antigen 50 to 100 times lower than that previously observed using either liposomes formulated with IL-2 and secreted lymphoma immunoglobulin or a prototype vaccine consisting of lymphoma immunoglobulin conjugated to keyhole limpet hemocyanin. The increased potency justifies testing similar patient-specific human vaccines prepared using extracts from primary tumor samples.