The Crosstalk between Host and Gut Microbiota Mediated by Immunoglobulin A

Abstract

The host develops an acquired immune system primarily based on immunoglobulin A (IgA) to control the gut microbiota, which is essential for maintaining host health. The production of high-affinity IgA, which binds specifically to gut bacteria, requires the selection of germinal center B cells by T follicular helper cells (TFH cells) in Peyer’s patches. Foxp3+ T cells and PD-1 expressed on TFH cells regulate the number and function of TFH cells, thereby regulating the selection process of germinal center B cells in the Peyer’s patches and the production of IgA appropriate for controlling the gut microbiota. As a result, a symbiotic relationship between the host and the gut microbiota is formed through IgA. However, long-term stimulation of the gut microbiota induces cellular senescence in gut germinal center B cells, leading to dysregulation of the gut microbiota due to decreased IgA production and diversity, ultimately resulting in age-related dysbiosis of the gut microbiota. These studies have highlighted the potential health risks associated with the gut microbiota, which are critical for maintaining the host’s health, in aging.