Host immune system and gut microbiota (GIA)

The host immune system and gut microbiota represent a complex, bidirectional communication network known as the gut-immune axis. The gut microbiota, consisting of trillions of microorganisms, is essential for the development and education of the host immune system, particularly in the maturation of gut-associated lymphoid tissues and the induction of regulatory T cells [1][2]. In return, the immune system regulates the composition and containment of the microbiota through mechanisms like IgA secretion and antimicrobial peptide production [3]. Disruptions in this symbiotic relationship, known as dysbiosis, are implicated in a wide range of conditions, including inflammatory bowel disease, metabolic syndrome, and autoimmune disorders [4]. Furthermore, the gut microbiota has emerged as a critical determinant of the efficacy of cancer immunotherapies, such as PD-1/PD-L1 inhibitors [5]. Therapeutic interventions targeting this axis, including probiotics, prebiotics, and fecal microbiota transplantation, aim to restore homeostasis and modulate systemic immune responses [6]. This interaction is also a key factor in the development of oral tolerance and the prevention of hypersensitivity to food antigens. Understanding this axis is vital for developing next-generation biotherapeutics that leverage microbial metabolites to treat systemic inflammation.

Other names

Gut-immune axisMicrobiota-immune crosstalkIntestinal microbiome-immune system interactionGut-microbiota-immune system axis

Modulation of the gut-immune axis occurs through the production of microbial metabolites like short-chain fatty acids (SCFAs), which induce regulatory T cell differentiation, and the activation of pattern recognition receptors (PRRs) that calibrate innate and adaptive immune responses [1][2]. Drugs and biotherapeutics can alter the microbial composition to shift the balance between pro-inflammatory and anti-inflammatory signals [6].