Gut immune cells and mucosal immune pathways

The gut immune system and its mucosal pathways represent a specialized branch of the immune system responsible for maintaining homeostasis at the body's largest interface with the external environment (Mowat & Agace, 2014). This system, primarily organized within the gut-associated lymphoid tissue (GALT), must balance robust defense against pathogens with tolerance toward dietary antigens and commensal microbiota (Sun et al., 2023). Key components include the intestinal epithelial barrier, intraepithelial lymphocytes (IELs), and IgA-secreting plasma cells, which are regulated by a complex network of cytokines such as TNF-α, IL-23, and IL-10 (Neurath, 2014). Dysregulation of these mucosal pathways is the primary driver of inflammatory bowel diseases (IBD), including Crohn's disease and ulcerative colitis, where an overactive immune response leads to chronic tissue damage (Feagan et al., 2013). Therapeutic interventions target specific nodes within this system, such as blocking lymphocyte trafficking via α4β7 integrin antagonism (e.g., vedolizumab) or neutralizing pro-inflammatory cytokines (e.g., infliximab, risankizumab) to restore mucosal healing (Pool et al., 2026).

Other names

Mucosal immune systemGut-associated lymphoid tissueGALTIntestinal immune systemIntestinal mucosal immunity

Therapeutic modulation of the mucosal immune system involves targeting specific molecular pathways to reduce inflammation and promote mucosal healing. This includes inhibiting lymphocyte trafficking to the gut by antagonizing the alpha-4 beta-7 (α4β7) integrin, neutralizing pro-inflammatory cytokines such as TNF-α, IL-12, and IL-23, or modulating intracellular signaling via JAK-STAT inhibition and S1P receptor sequestration.