Small intestinal immune system (GALT)

The small intestinal immune system, primarily organized as gut-associated lymphoid tissue (GALT), represents a sophisticated immunological network tasked with maintaining homeostasis at the body's largest mucosal surface. It functions by balancing the active exclusion of pathogens with the induction of oral tolerance toward dietary antigens and the commensal microbiome (Mowat, 2003). Anatomically, it consists of organized lymphoid tissues like Peyer's patches and mesenteric lymph nodes, alongside diffuse effector cells in the lamina propria and epithelium (Mowat & Agace, 2014). Pathological activation of this system underlies major gastrointestinal disorders, including Crohn's disease and Celiac disease, characterized by a breakdown in tolerance and chronic inflammation (Neurath, 2014). From a drug development perspective, the system is not a single target but a site of action for numerous biologics and small molecules that target specific cytokines or cell-surface receptors to control leukocyte recruitment and inflammatory signaling (Feagan et al., 2013).

Other names

Gut-associated lymphoid tissueIntestinal mucosal immune systemGALTSmall intestine immune system

Modulation of lymphocyte trafficking, neutralization of pro-inflammatory cytokines, and induction of immune tolerance.