title: Sequential development of intraepithelial gamma delta and alpha beta T lymphocytes expressing CD8 alpha beta in neonatal rat intestine: requirement for the thymus.
abstract: Previous studies in congenitally athymic nude rats have suggested that the thymus is important for the development of intestinal T cells. Here we have examined the effect of the nude mutation on intraepithelial lymphocyte (IEL) development from the perinatal period. By immunohistochemistry it was shown that CD3(-)CD8 alpha alpha + putative IEL precursors colonized the epithelium of both normal and athymic neonatal rats. Mature T cells, however, did not develop in athymic neonates. In normal rats, gamma delta T cells were present at birth and alpha beta T cells appeared within 8 days of postnatal life. At this age, the composition and relative number of intraepithelial T cells were similar to that in normal adult rats, with the exception that most neonatal T-cell receptor-gamma delta + and -alpha beta + IEL expressed CD8 beta. By contrast, extrathymic T-cell maturation in the gut of congenitally athymic rats occurred slowly, as CD3+ IEL did not appear until 4-6 months of age. These intraepithelial T cells displayed variable phenotypes and appeared to be induced by environmental antigens as they were not found in isolator-kept old nudes. In conclusion, the present results indicate that the major colonization of the gut epithelium with gamma delta and alpha beta T cells expressing CD8 alpha beta takes place perinatally and requires the presence of the thymus. The developmental relationship between these neonatal T cells and more immature CD3- CD8 alpha alpha +/- IEL remains elusive.
authors.affiliation: Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), University of Oslo, Norway.
authors.forename: L
authors.initials: L
authors.lastname: Helgeland
authors.forename: P
authors.initials: P
authors.lastname: Brandtzaeg
authors.forename: B
authors.initials: B
authors.lastname: Rolstad
authors.forename: J T
authors.initials: JT
authors.lastname: Vaage
mesh_terms: D000375:Aging / Q000276:immunology; D000818:Animals; D000831:Animals, Newborn; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D004848:Epithelium / Q000276:immunology; D007124:Immunoenzyme Techniques; D007413:Intestinal Mucosa / Q000276:immunology*; D007583:Jejunum / Q000276:immunology; D008198:Lymph Nodes / Q000276:immunology*; D051381:Rats; D011923:Rats, Nude; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology*
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta