Peptide vaccination using nonionic block copolymers induces protective anti-viral CTL responses

High molecular weight nonionic block copolymers have been developed as vacc ine adjuvants. We employed these adjuvants in water-in-oil emulsion and mul tiple emulsion formulations with a synthetic peptide-based antigen vaccine to test their ability to prime anti-viral CD8(+) T cell responses. Vaccines were made using the H-2(d)-restricted immunodominant peptide from lymphocy tic choriomeningitis virus (LCMV), NP118-126, and administered to BALB/c By J (H-2(d)) mice. Peptide-containing emulsions were able to induce NP118-126 specific CTL and IFN-gamma secreting CD8(+) T cells in the vaccinated mice and these responses were maintained for at least 90 days post immunization . At all times, the responses induced by the copolymer formulations were eq ual to, or better than, formulations based on incomplete Freund's adjuvant (IFA). In addition, the responses induced by prophylactic vaccination using the multiple emulsion formulation resulted in accelerated viral clearance following infection with a strain of LCMV (clone 13) that causes a persiste nt infection in naive adult mice. These results indicate that peptide vacci nation using a formulation based on high molecular weight nonionic block co polymer in a simple water-in-oil or a multiple emulsion format can induce v irus-specific CD8(+) T cell responses and confer protection sufficient enou gh to prevent the establishment of a persistent infection. (C) 1999 Elsevie r Science Ltd. All rights reserved.