Immunomodulatory Effects of Gut Microbiota

The human gastrointestinal tract harbours a complex microbial ecosystem that exerts profound effects on the host immune system. Commensal bacteria and their metabolic products interact with intestinal epithelial cells, resident immune populations and distant sites to calibrate both innate and adaptive immunity. Key mechanisms include the production of short-chain fatty acids that influence T-regulatory cell differentiation, structural components such as peptidoglycan and lipopolysaccharide that engage pattern recognition receptors, and exopolysaccharides that modulate mucosal barrier integrity. This multilayered dialogue maintains homeostasis, promotes tolerance to dietary and microbial antigens, and primes the host against pathogens. Dysbiosis or loss of beneficial taxa can disrupt these interactions, contributing to inflammatory bowel disease, metabolic disorders and systemic immune dysregulation. Emerging insights have revealed strain-specific effects, inter-kingdom signalling and feedback loops between diet, microbiota composition and host immunity. A deeper understanding of these immunomodulatory circuits offers avenues for microbiota-targeted therapies, probiotics with bespoke bioactive compounds and personalised nutritional interventions to restore immune equilibrium.

Research from Nature Portfolio

No recent Nature Portfolio content available.

Immunomodulatory Effects of Gut Microbiota publication trend

The graph below shows the total number of articles in immunomodulatory effects of gut microbiota across all publications each year (not limited to Nature Index journals).

Technical terms

Exopolysaccharide: Polysaccharide secreted by bacteria that influences biofilm formation and host immune signalling.

Lipopolysaccharide (LPS): Glycolipid in Gram-negative bacterial outer membranes that interacts with Toll-like receptor 4, with structural variants exerting pro- or anti-inflammatory effects.

Peptidoglycan: Rigid polymer of sugars and amino acids forming bacterial cell walls, recognised by innate immune receptors to trigger host responses.

Short-chain fatty acids (SCFAs): Metabolic end-products of microbial fermentation that serve as signalling molecules to regulate T-cell differentiation and epithelial barrier function.

Toll-like receptor 4 (TLR4): Innate immune receptor detecting LPS and other ligands, initiating downstream inflammatory or tolerogenic pathways.

References

1. Immunogenic molecules associated with gut bacterial cell walls: chemical structures, immune-modulating functions, and mechanisms. Protein & Cell (2023).
2. Total Lipopolysaccharide from the Human Gut Microbiome Silences Toll-Like Receptor Signaling. mSystems (2017).
3. Interactions of Surface Exopolysaccharides From Bifidobacterium and Lactobacillus Within the Intestinal Environment. Frontiers in Microbiology (2018).
4. Like Cures Like: Pharmacological Activity of Anti-Inflammatory Lipopolysaccharides From Gut Microbiome. Frontiers in Pharmacology (2020).
5. Molecules Produced by Probiotics and Intestinal Microorganisms with Immunomodulatory Activity. Nutrients (2020).