Chemical and biological adjuvants capable of potentiating tumor cell vaccine.

With an L1210 tumor vaccine model, three biological and two chemical agents were tested for their ability to act as adjuvants. Adjuvant was administered with irradiated L1210 cells to immunize mice against this poorly immunogenic tumor. Two chemicals, pyran copolymer and glucan, and one biological, Brucella abortus strain 456 ether extract, were shown to be strong stimulators of antitumor immunity. Vaccination with irradiated tumor cells or adjuvant alone did not produce host resistance. Optimal immunity to challenge was produced by concomitant administration of either pyran copolymer, glucan, or B. abortus strain 456 ether extract with L1210 vaccine. Antitumor immunity was maximally expressed when vaccine and adjuvant were administered i.p. Evidence for systemic immunity was demonstrated when challenge was at a distal s.c. site. Mice immune to challenge were found to be refractory to a later rechallenge.