Gut microbiota-host immune system axis (GIA)

The gut microbiota-host immune system axis is a complex, bidirectional communication network essential for maintaining systemic homeostasis and immune tolerance. This interaction occurs primarily at the intestinal mucosa, where the gut-associated lymphoid tissue (GALT) monitors commensal and pathogenic microbes (Belkaid & Hand, 2014, Science). The microbiota influences immune cell development, particularly the differentiation of regulatory T cells (Tregs) and Th17 cells, through the secretion of metabolites such as short-chain fatty acids (SCFAs) and bile acids (Round & Mazmanian, 2009, Nature Reviews Immunology). Dysbiosis, or an imbalance in this microbial community, is strongly associated with the pathogenesis of inflammatory bowel disease (IBD), autoimmune conditions, and metabolic syndrome (Lynch & Pedersen, 2016, NEJM). Furthermore, the composition of the gut microbiome has been shown to significantly impact the clinical response to cancer immunotherapies, such as PD-1 inhibitors (Gopalakrishnan et al., 2018, Science). Therapeutic interventions targeting this axis include probiotics, prebiotics, and fecal microbiota transplantation (FMT), which aim to restore a healthy microbial-immune balance.

Other names

Gut-immune axisMicrobiome-immune crosstalkIntestinal microbiota-immune system interactionGut microbial community and host immune system

Modulation of immune cell populations via microbial metabolites such as short-chain fatty acids (SCFAs) binding to G-protein coupled receptors (GPR41/43), activation of pattern recognition receptors (PRRs) like Toll-like receptors (TLRs), and induction of Foxp3+ regulatory T cells (Tregs).