The immunogenicity of vaccines is enhanced by co-administering a synthetic glycolipid, designated PBS-57, with the vaccine. PBS-57 has the ability to stimulate both a cell-mediated and humoral immune response. Co-administration of PBS-57 with a vaccine may be used in methods to stimulate one or more of a humoral immune response, a CD4+ T cell response, and a CD8+ cytotoxic T cell response.
