The interplay between the gut microbiota and the immune system

Abstract

The impact of the gut microbiota on immune homeostasis within the gut and, importantly, also at systemic sites has gained tremendous research interest over the last few years. The intestinal microbiota is an integral component of a fascinating ecosystem that interacts with and benefits its host on several complex levels to achieve a mutualistic relationship. Host-microbial homeostasis involves appropriate immune regulation within the gut mucosa to maintain a healthy gut while preventing uncontrolled immune responses against the beneficial commensal microbiota potentially leading to chronic inflammatory bowel diseases (IBD). Furthermore, recent studies suggest that the microbiota composition might impact on the susceptibility to immune-mediated disorders such as autoimmunity and allergy. Understanding how the microbiota modulates susceptibility to these diseases is an important step toward better prevention or treatment options for such diseases.

Keywords: IgA; allergies; autoimmunity; homeostasis; innate lymphoid cells; microbial conditioning; microbiota; regulatory T cells.

Figure 1. Interplay between microbiota composition and disease susceptibility. Antibiotics, diet, mode of delivery at birth, and genetics all seem to have a significant impact on the microbiota composition, which in turn might affect the susceptibility to immune mediated disorders.

Figure 2. Overview of the cytokine network regulating innate and adaptive immune-microbiota interactions. The immune cell types and cytokines involved in sensing the microbiota and controlling innate and adaptive immune homeostasis are illustrated.