Role of postnatal acquisition of the intestinal microbiome in the early development of immune function

J Pediatr Gastroenterol Nutr. 2010 Sep;51(3):262-73. doi: 10.1097/MPG.0b013e3181e1a114.

Abstract

Objectives: Therapy with broad-spectrum antibiotics is a common practice for premature infants. This treatment can reduce the biodiversity of the fecal microbiota and may be a factor in the cause of necrotizing enterocolitis. In contrast, probiotic treatment of premature infants reduces the incidence of necrotizing enterocolitis. We hypothesized that 1 mechanism for these observations is the influence of bacteria on postnatal development of the mucosal immune system.

Materials and methods: Expression of immune molecules and microbial sensors was investigated in the postnatal mouse gastrointestinal tract by real-time polymerase chain reaction. Subsequently, 2-week-old specific pathogen-free and microbial-reduced (MR; antibiotic treated) mice were compared for immune molecule and microbial sensor expression, mesenteric lymph node T-cell numbers and activation, intestinal barrier function/permeability, systemic lymphocyte numbers, and T-cell phenotype commitment.

Results: Toll-like receptor 2, 4, and 5 expression was highest in 2-week-old specific pathogen-free mice, and this expression was decreased in MR mice. There was no difference in intestinal tight-junctional function, as evaluated by fluorescein isothiocyanate-dextran uptake, but MR mice had increased bacterial translocation across the intestinal epithelial barrier. MR mice had significantly fewer splenic B cells and mesenteric lymph node CD4+ T cells, but there were normal numbers of splenic T cells. These systemic T cells from MR mice produced more interleukin-4 and less interferon-gamma and IL-17, indicative of maintenance of the fetal, T-helper cell type 2 phenotype.

Conclusions: The present study shows that intestinal commensal microbiota have an influence on early postnatal immune development. Determining specific bacteria and/or bacterial ligands critical for this development could provide insight into the mechanisms by which broad-spectrum antibiotics and/or probiotic therapy influence the development of the mucosal immune system and mucosal-related diseases.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Anti-Bacterial Agents / pharmacology
  • Bacterial Translocation
  • CD4-Positive T-Lymphocytes / metabolism
  • Cytokines / metabolism
  • Gastrointestinal Tract / drug effects
  • Gastrointestinal Tract / immunology
  • Gastrointestinal Tract / microbiology*
  • Immune System / cytology
  • Immune System / physiology*
  • Interferon-gamma / metabolism
  • Interleukin-17 / metabolism
  • Interleukin-4 / metabolism
  • Intestinal Mucosa / drug effects
  • Intestinal Mucosa / immunology*
  • Lymph Nodes / immunology
  • Mice
  • Mice, Inbred C57BL
  • Reverse Transcriptase Polymerase Chain Reaction
  • Spleen / immunology
  • T-Lymphocytes / metabolism
  • Toll-Like Receptors / metabolism*

Substances

  • Anti-Bacterial Agents
  • Cytokines
  • Interleukin-17
  • Toll-Like Receptors
  • Interleukin-4
  • Interferon-gamma