Gut: Key Element on Immune System Regulation

Abstract

lymphocytes. This unique microenvironment present in the intestinal lamina propria (LP) and mesenteric lymph nodes (mLN) induce tolerance to innocuous antigens from the diet, known as Oral Tolerance. Antigens sampled by intestinal epithelium cells are transferred to specialized dendritic cells, residing in the LP, which migrate to the mesenteric lymph nodes where they participate in the induction of regulatory T cells (Treg). Understanding these phenomena may establish the intestinal mucosa as a tool in therapy of inflammatory bowel diseases and immunological disorders.

Frequency of Effector Memory Cells Expressing Integrin α4β7 Is Associated With TGF-β1 Levels in Therapy Naïve HIV Infected Women With Low CD4+ T Cell Count

“…Integrin α 4 β 7 is exclusively expressed on immune cells to facilitate gut homing by binding to MAdCAM-1 ( 48 ) which is constitutively expressed on endothelial venules of the gut. Intestinal mucosa is subjected to high antigenic exposure which is mitigated by GALT, the largest reservoir of immune cells ( 49 ). In addition to tissue resident immune cells, GALT has a constant flux of immune cells from distal sites including other mucosal surfaces via systemic blood circulation for appropriate priming of adaptive immune cells ( 50 ).…”

Rice protein concentrate as a fish meal substitute in Oreochromis niloticus: Effects on immune response, intestinal cytokines, Aeromonas veronii resistance, and gut microbiota composition

“…However, GALT may develop tolerance to ingested dietary antigens, despite its ability to generate quick and strong reactions against foreign substances [94,95]. GALT maturation is affected by feeds because the proteins in feeds affect the abundance of resident lymphocytes [96]. The effects of feeds and protein sources on the immune system can be determined by measuring the expression of pathogen-resistant pro-inflammatory cytokines (e.g., TNFα and IL-1β) and mucosal tolerance cytokines (e.g., TGFβ and IL-10β) in the intestine [47].…”

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“…According to its structure and function, GALT can be divided into two distinct groups: GALT with diffuse structure/effector sites (intestinal lamina propria and IELs) [41] and GALT with dense structure/inductive sites (PPs, mesenteric lymph nodes, cecal patches, colonic patches, ILFs, and crypto patches) [2].…”

“…IELs maintain the integrity of the intestinal epithelial barrier, respond to the invasion of infectious agents, and participate in tissue renewal [41].…”

“…The following components characterize the structure of PPs: individual follicles (tens to hundreds, mainly constituted by many B-cells, maturated in the GCs) [34,50], macrophages and DCs [41], FAE (with many IELs), and associated subepithelial dome (SED) [located between follicles and FAE and containing memory CD4(+) T-cells, and IgA, IgM, and IgG secretory B-cells] [34,51]. The small T-cells are situated adjacent to the B-cell follicles in the parafollicular zone [36].…”