Utilization of gut environment-mediated control system of host immunity in the development of vaccine adjuvants.

Vaccination is one of the most powerful strategies for the preventive and therapeutic control of infectious diseases and other diseases such as cancer. To maximize the effectiveness of vaccines, it is necessary to modify the immune responses by means of adjuvants. The gut environment, including commensal bacteria and dietary components, has been proven to be able to mediate host immunity. An understanding of gut microbiota-related regulation of immune responses has revealed the potential adjuvanticity of particular microbiota-derived compounds, driving exploration into their development as vaccine adjuvants. In this review, we discuss how commensal bacteria and compounds derived from them regulate host immune responses, and we propose the potential application of these compounds as vaccine adjuvants.