title: Developmental changes in intraepithelial T lymphocytes and NK cells in the small intestine of neonatal rats.
abstract: The main objective of this study was to characterize developmental changes in small intestinal intraepithelial lymphocyte (IEL) subpopulations during the suckling period, thus contributing to the understanding of the development of diffuse gut-associated lymphoid tissue (GALT) and to the identification of early mechanisms that protect the neonate from the first contact with diet and gut microbial antigens. The study was performed by double labeling and flow cytometry in IEL isolated from the proximal and distal small intestine of 1- to 21-d-old Lewis rats. During the suckling period, intraepithelial natural killer (NK) cells changed from a typical systemic phenotype, CD8+, to a specific intestinal phenotype, CD8-. Analysis of CD8+ IEL revealed a progressive increase in the relative number of CD8+ IEL co-expressing TCRalphabeta, cells associated with acquired immunity, whereas the percentage of CD8+ cells expressing the NK receptor, i.e. cells committed to innate immunity, decreased. At weaning, IEL maturity was still not achieved, as revealed by a phenotypic pattern that differed from that of adult rats. Thus, late after weaning, the regulatory CD8+CD4+ T IEL population appeared and the NK population declined. In summary, the intestinal intraepithelial compartment undergoes changes in its lymphocyte composition associated with the first ingestion of food. These changes are focused on a relatively high proportion of NK cells during the suckling period, and after weaning, an expansion of the regulatory CD8+CD4+ T cells.
authors.affiliation: Department of Physiology, Faculty of Pharmacy, University of Barcelona, E-08028 Barcelona, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Pérez-Cano
authors.forename: Cristina
authors.initials: C
authors.lastname: Castellote
authors.forename: Ana M
authors.initials: AM
authors.lastname: González-Castro
authors.forename: Carme
authors.initials: C
authors.lastname: Pelegrí
authors.forename: Margarida
authors.initials: M
authors.lastname: Castell
authors.forename: Angels
authors.initials: A
authors.lastname: Franch
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D016516:CD4-CD8 Ratio; D005260:Female; D005455:Fluorescent Antibody Technique; D007421:Intestine, Small / Q000166:cytology*; D007694:Killer Cells, Natural / Q000166:cytology*; D008297:Male; D010641:Phenotype; D011247:Pregnancy; D051381:Rats; D011917:Rats, Inbred Lew; D013601:T-Lymphocytes / Q000166:cytology*