title: Dependence of epithelial growth of the small intestine on T-cell activation during weaning in the rat.
abstract: OBJECTIVE
  Intestinal crypt hyperplasia is associated with local T-cell activation in both clinical and experimental examples of immunologically mediated enteropathy. This suggests that T cell-derived factors may be trophic for epithelial proliferation in the intestine postnatally. The purpose of this study was to investigate T-cell activity during weaning in the rat and to investigate immune dependence of intestinal growth on T-cell activation.
  
  
  METHODS
  The expression of interleukin-2 receptor (IL-2R) by mesenteric lymph node T cells was investigated from days 14 to 160 of life. Rats were treated with monoclonal antibodies against the IL-2R that were nonblocking (control) or blocking (experimental) from day 7, and intestinal growth was assessed at days 19, 25, and 29 of life.
  
  
  RESULTS
  The mean +/- SEM of T cells expressing the IL-2R during weaning (days 15-28) was 6.1% +/- 0.3% compared with 3.3% +/- 0.3% at other ages (P < 0.001). The small intestine in rats treated with blocking antibody had reduced crypt length and mitotic count compared with control animals.
  
  
  CONCLUSIONS
  Weaning is associated with activation of T cells and blockade of the IL-2R reduces intestinal growth.
authors.affiliation: Gastroenterology Unit, The Queen Elizabeth Hospital, Woodville South, South Australia, Australia.
authors.forename: F M
authors.initials: FM
authors.lastname: Thompson
authors.forename: G
authors.initials: G
authors.lastname: Mayrhofer
authors.forename: A G
authors.initials: AG
authors.lastname: Cummins
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D003877:Dermatitis, Contact / Q000276:immunology; D004848:Epithelium / Q000254:growth & development / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D007413:Intestinal Mucosa / Q000254:growth & development / Q000276:immunology; D007421:Intestine, Small / Q000254:growth & development* / Q000276:immunology; D016014:Linear Models; D008213:Lymphocyte Activation; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D015375:Receptors, Interleukin-2 / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism / Q000502:physiology*; D014886:Weaning
chemical_list: D000911:Antibodies, Monoclonal; D015375:Receptors, Interleukin-2