AIDS vaccines and adjuvant formulations.

The AIDS epidemic is too large to continue ignoring prevention programs that appear to work. In this review the promising experimental immunogens and how close they are to the optimal requirements for a preventive vaccine are presented. Adjuvants and adjuvant formulations (mainly mixtures of adjuvants with suitable vehicles) can help in solving some specific problems of AIDS vaccines: overcome the variable nature of HIV subtypes, generate both antibody and T-cell response, induce mucosal immunity, avoid enhancing or autoimmune antibodies and distinguish vaccine-induced seropositivity from natural HIV infection. The following categories of adjuvants are discussed: alum, other mineral and bacterial cell-wall derived adjuvants, cytokines, carriers and vehicles. Although many specific mechanisms of the relative effectiveness of adjuvants have been clarified by recent advances in basic immunology the best adjuvant formulation remains largely empirical. A standardized protocol for preclinical testing of adjuvants for AIDS vaccines is a priority task.