EFFICACY OF SYNTHETIC VACCINES IN THE INDUCTION OF CYTOTOXIC T-LYMPHOCYTES - COMPARISON OF THE COSTIMULATING SUPPORT PROVIDED BY HELPER T-CELLS AND LIPOAMINO ACID

Synthetic vaccines that specifically induce active immunity mediated by cytotoxic T lymphocytes (CTL) are of great interest considering the central role of these cells in immune responses against intracellular antigens. The influence of specific T helper (Th) cell recruitment and of the potent immunostimulating lipoamino acid tripalmitoyl-S-glycerylcysteine (P3C) on CTL mediated immunity induced by CTL epitopes was analysed and compared. Synthetic peptides that represent CTL epitopes were found to be inefficient for CTL priming. However, when combined with peptides that contain Th cell epitopes, with proteins that carry multiple Th cell epitopes or with P3C, efficient priming of CTL was obtained. The costimulating support by P3C and proteins resulted in high cytolytic activities already after 9 days whereas, in the case of single helper epitopes, incubation periods of about 4 weeks were required. The effects of P3C and helper epitopes were additive.