Vaccine Adjuvants: A New Hope for Effective Immunizations

Two important issues regarding the use of immunization to control infections and malignancies in the future are: 1) the need to render poorly immunogenic, often highly purified, antigens more effective; and 2) the desire to direct the immune response in specific ways to achieve the most relevant response for each disease. The first issue can be solved by understanding and then recreating and enhancing the antigen presentation process by a broad range of vaccine adjuvants. The second issue requires careful selection among the adjuvants to allow directing of the immune response in the most appropriate manner. For example, in different settings expansion of a B cell response, cytotoxic T cell response, or enhancement of either a Thl or Th2 subset response may be desired. These goals are accomplished by the use of several newly developed non-cytokine adjuvants, or by direct injection of the relevant cytokines. Some non-cytokine molecular adjuvants and cytokines used as adjuvants have already been proven effective in animal models and/or in clinical trials. Here, we review the present state of the art in the use of vaccine adjuvants for control of various infectious diseases.