MAIT cell activation and recruitment in inflammation and tissue damage in acute appendicitis

Sci Adv. 2024 Jun 14;10(24):eadn6331. doi: 10.1126/sciadv.adn6331. Epub 2024 Jun 12.

Abstract

Mucosal-associated invariant T (MAIT) cells are antimicrobial T cells abundant in the gut, but mechanisms for their migration into tissues during inflammation are poorly understood. Here, we used acute pediatric appendicitis (APA), a model of acute intestinal inflammation, to examine these migration mechanisms. MAIT cells were lower in numbers in circulation of patients with APA but were enriched in the inflamed appendix with increased production of proinflammatory cytokines. Using the patient-derived appendix organoid (PDAO) model, we found that circulating MAIT cells treated with inflammatory cytokines elevated in APA up-regulated chemokine receptors, including CCR1, CCR3, and CCR4. They exhibited enhanced infiltration of Escherichia coli-pulsed PDAO in a CCR1-, CCR2-, and CCR4-dependent manner. Close interactions of MAIT cells with infected organoids led to the PDAO structural destruction and death. These findings reveal a previously unidentified mechanism of MAIT cell tissue homing, their participation in tissue damage in APA, and their intricate relationship with mucosal tissues during acute intestinal inflammation in humans.

MeSH terms

  • Acute Disease
  • Appendicitis* / immunology
  • Appendicitis* / pathology
  • Appendix / immunology
  • Appendix / pathology
  • Cell Movement
  • Child
  • Cytokines / metabolism
  • Female
  • Humans
  • Inflammation* / immunology
  • Inflammation* / metabolism
  • Inflammation* / pathology
  • Intestinal Mucosa / immunology
  • Intestinal Mucosa / metabolism
  • Intestinal Mucosa / pathology
  • Lymphocyte Activation / immunology
  • Male
  • Mucosal-Associated Invariant T Cells* / immunology
  • Mucosal-Associated Invariant T Cells* / metabolism
  • Organoids

Substances

  • Cytokines