DEVELOPMENT AND APPLICATION OF PROVAX(TM) ADJUVANT FORMULATION FOR SUBUNIT CANCER VACCINES

A major challenge facing the development of subunit vaccines comprised of well-defined recombinant antigens is their weak immunogenicity and inability to induce effective cytotoxic T cell (CTL) responses. Adjuv ants aimed at increasing the immunogenicity of recombinant antigens re main a focus in vaccine development. The potency of an adjuvant is lin ked to specific stimulation of T cell responses, involving TH1 and TH2 subsets of CD4(+) T helper cells and CD8(+) CTL and B cell-mediated a ntibody responses. As a result of the existence of two distinct intra- cellular pathways for antigen processing,: immunization with exogenous antigens often shows a greater propensity for T helper and antibody r esponses, but not CD8(+) CTL responses. However, existing experimental evidence suggests that CD8(+) CTLs, which are critical in the elimina tion of viral-infected and neoplastic cells, can be elicited with solu ble antigens when delivered in appropriate formulations or adjuvants. This review focuses on the properties of PROVAX(TM) adjuvant in induci ng antigen-specific CTL responses, antibody responses and tumor regres sion in experimental models and its potential application for the deve lopment of recombinant cancer vaccines. (C) 1998 Elsevier Science B.V.