Regulation of innate and adaptive immunity by the vaccine adjuvant alum

Abstract

While many licensed vaccines consist of whole or inactivated pathogens, there is a move toward vaccines based on purified antigens which although safer are generally less immunogenic and therefore require adjuvants to trigger protective immunity. Alum, the most common adjuvant, has a record of successful use in vaccines, where an antibody-mediated immune response can confer protective immunity. However, alum is a poor inducer of cellular immune responses. The mechanism underlying this selective enhancement of humoral responses is still not well understood. Here, to gain an improved insight into its mode of action, innate immune responses to alum and their impact on adaptive immune responses were studied.