Adjuvant Formulations for Experimental Vaccines

An adjuvant (immunopotentiator), when added to a vaccine, will enhance the immunogenicity of the antigen with the stimulation of an elevated humoral immune response. Some adjuvants may also stimulate a cell-mediated response against the antigen. One advantage of including an adjuvant in the vaccine mixture is that smaller quantities of the antigen are usually required to stimulate a good response. New synthetic experimental vaccines may require the presence of an adjuvant to achieve an immunogenic response. There is no single universal adjuvant, but numerous adjuvants are available alone (e.g., muramyl dipeptide and Quil A derivatives), or conjugated to the antigen (e.g., Immune-stimulating complexes [ISCOMs]), or in mixtures (e.g., Montanides, Guildhay or MF-59 adjuvants). The adjuvant selected will be based on experimental data produced with a variety of antigen preparations, taking into consideration the nature and dose to be administered, the route of vaccine administration, and any contraindications. For human vaccines, it should be remembered that aluminum salt adjuvants have been the only licensed preparations for the past sixty yr.