Vaccines have provided the most beneficial contribution to public health. Generating antigen specific antibody responses and long lasting memory are crucial for the protective immunity offered by vaccination. Unfortunately, not all individuals respond in the same manner to vaccine formulations. The microbiota is established during postnatal development and remains relatively stable for long periods. Our understanding that the microbiota can have beneficial effects on human health has led immunologists to investigate how these organisms may shape the innate and adaptive immune responses of the host. In this review we examine the impact of the microbiota on the host immune responses to vaccines and explore the possibility of how the commensal bacteria may act as natural adjuvants to enhance systemic immune responses to vaccines.


microbiota, vaccines, B cells, innate immunity, adaptive immunity, adjuvants, LPS