Innate immunity in the small intestine

Rebeca Santaolalla, Maria T Abreu

Research output: Contribution to journalArticle

60 Citations (Scopus)


PURPOSE OF REVIEW: This article reviews the most recent publications on innate immunity in the small intestine. We will go over the innate immune receptors that act as sensors of microbial presence or cell injury, Paneth cells as the main epithelial cell type that secrete antimicrobial peptides, and mucosal production of immunoglobulin A (IgA). In addition, we will give an update on examples of imbalance of the innate immune response resulting in clinical disease with the most relevant example being Crohn's disease. RECENT FINDINGS: Toll-like receptors (TLRs) are involved in B-cell homing to the intestine, rejection of small intestinal allografts, and recruitment of mast cells. The TLR adaptor Toll/interleukin-1 receptor domain-containing adapter-inducing interferon-β is necessary to activate innate immunity after Yersinia enterocolitica infection. Moreover, MyD88 is required to keep the intestinal microbiota under control and physically separated from the epithelium, and RegIIIγ is responsible for the bacterial segregation from the lining epithelial cells. In Crohn's disease, ATG16L1 T300A variant promotes a proinflammatory response; and miR-196 downregulates a protective immunity-related GTPase family M protein (IRGM) polymorphism leading to impaired clearance of adherent Escherichia coli in the intestine. SUMMARY: The intestine is continuously exposed to dietary and microbial antigens. The host has to maintain intestinal homeostasis to keep the commensal and pathogenic bacteria under control. Some of the mechanisms to do so are by expression of innate immune receptors, production of antimicrobial peptides, secretion of IgA, or autophagy of intracellular bacteria. Unfortunately, in some cases the innate immune response fails to protect the host and chronic inflammation, transplant rejection, or other disorders may occur.

Original languageEnglish
Pages (from-to)124-129
Number of pages6
JournalCurrent Opinion in Gastroenterology
Issue number2
StatePublished - Mar 1 2012


Innate Immunity
Small Intestine
Toll-Like Receptors
Crohn Disease
Immunoglobulin A
Epithelial Cells
Yersinia Infections
Paneth Cells
Yersinia enterocolitica
Interleukin-1 Receptors
GTP Phosphohydrolases
Graft Rejection
Mast Cells


  • Crohn's disease
  • immunoglobulin A
  • microbiota
  • nucleotide-binding oligomerization domain
  • Paneth cell
  • Toll-like receptor

ASJC Scopus subject areas

  • Gastroenterology

Cite this

Innate immunity in the small intestine. / Santaolalla, Rebeca; Abreu, Maria T.

In: Current Opinion in Gastroenterology, Vol. 28, No. 2, 01.03.2012, p. 124-129.

Research output: Contribution to journalArticle

Santaolalla, Rebeca ; Abreu, Maria T. / Innate immunity in the small intestine. In: Current Opinion in Gastroenterology. 2012 ; Vol. 28, No. 2. pp. 124-129.
title = "Innate immunity in the small intestine",
abstract = "Lippincott Williams & Wilkins.",
keywords = "Crohn's disease, immunoglobulin A, microbiota, nucleotide-binding oligomerization domain, Paneth cell, Toll-like receptor",
author = "Rebeca Santaolalla and Abreu, {Maria T}",
year = "2012",
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doi = "10.1097/MOG.0b013e3283506559",
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journal = "Current Opinion in Gastroenterology",
issn = "0267-1379",
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