Recent Advances in Vaccine Adjuvants

Adjuvants are substances distinct from antigens that enhance T and B cell activation mainly by promoting the accumulation and activation of antigen presenting cells (APCs) at the site of antigen exposure. Adjuvants (Latin: “adjuvare,” meaning “to help”) are designed to improve poorly immunogenic vaccines. Adjuvants were originally described by Ramon as ‘substances used in combination with a specific antigen that produced a more robust immune response than the antigen alone,’ thus encompassing a wide range of materials. One of the most important strategies for the development of effective new vaccines is the selection and usage of a suitable adjuvant. Immunologic adjuvants play a very important role in enhancing vaccine potency by improving the humoral and cell-mediated immune responses to vaccine antigens. In this review, we summarize the recent advances that are taking place in the development of potent adjuvants in human and veterinary vaccines.