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Table 1 Summary of the role of amino acids in GALT and the intestine

From: The immune modifying effects of amino acids on gut-associated lymphoid tissue

Amino acid Functions
Glutamine • Oxidative substrate for immune cells and IECs
• Precursor for glutamate/GSH
• Intestinal growth, structure and function (young animals and disease states)
• Supports proliferative rates and reduces apoptosis of IECs
• Protects against E.coli/LPS-induced damage to intestinal structure and barrier function
• Lowers inflammatory and increases immunoregulatory cytokine production
• Improves the proliferative responses of IELs and MLN cells
• Intestinal IgA levels
  • Increases lymphocyte numbers in PP, lamina propria and IELs
Glutamate • Oxidative substrate for immune cells and IECs
• Precursor for GSH and other amino acids (i.e. arginine)
• Intestinal growth, structure and function
• Acts as Immunotransmitter between dendritic cells and T-cells*
  • Facilitates T-cell proliferation and Th1 and proinflammatory cytokine production
Arginine • Precursor for NO and glutamate in IECs and immune cells
• Intestinal growth, structure and function
• Supports microvasculature of intestinal mucosa
• Increases expression of HSP70 to protect intestinal mucosa
• Protects against E.coli/LPS-induced damage to intestinal structure and barrier function
• Facilitates neutrophil and macrophage killing through iNOS-mediated NO production
• Increases intestinal IgA levels
• Lowers inflammatory cytokine levels in intestine
  • Increases T-lymphocytes in lamina propria, PPs, intraepithelial spaces
Methionine & Cysteine • Precursor for GSH, taurine and cysteine
• Reduces intestinal oxidative stress
• Intestinal structure
• Increases goblet cells and proliferating crypt cells
  • Protects against DSS-induced intestinal damage (colitis model) by lowering inflammation, crypt damage and intestinal permeability.
Threonine • Mucin synthesis
• Intestinal structure and function
  • Intestinal IgA levels
  1. *No direct evidence of effects on immune cells in GALT.