title: Proliferative recruitment of intestinal intraepithelial lymphocytes after microbial colonization of germ-free mice.
abstract: Intraepithelial lymphocytes (IEL), particularly alpha beta TCR-bearing IEL (alpha beta-IEL), dramatically increase in number after microbial colonization of formerly germ-free (ex-GF) mice (Umesaki et al., Immunology 1993. 79: 32). In this study, the kinetics of expansion of IEL after microbial colonization in ex-GF mice were investigated by the bromodeoxyuridine (BrdUrd) continuous labeling method. In GF mice, gamma delta- and alpha beta-IEL were gradually labeled with BrdUrd, reaching approximately 30% and 15% labeling, respectively, after 10 days of continuous BrdUrd labeling. In conventional (CV) mice, the percentage of BrdUrd-labeled alpha beta-IEL was a little higher than that for gamma delta-IEL. The maximal labeling for alpha beta-IEL and gamma delta-IEL reached 50-60% and 40%, respectively, in 10 days. In the case of conventionalized ex-GF mice, continuous labeling was started 11 days after microbial colonization of GF mice because alpha beta-IEL outnumbered gamma delta-IEL during this period. In this case, 75% of alpha beta-IEL and 67% of gamma delta-IEL were labeled with BrdUrd in 10 days. On the other hand, the apparent half lives of alpha beta-IEL and gamma delta-IEL were 10 and 20 days, respectively in CV mice. These results strongly suggest that the number of IEL, particularly alpha beta-IEL, increases after microbial colonization through recruitment into the cell cycle of a large proportion of IEL or their immediate precursors. The difference in the relative BrdUrd-labeling rate of alpha beta-IEL to that of gamma delta-IEL between germ-free and conventionalized mice indicates a preferential increase in the alpha beta-IEL subset during the course of conventionalization.
authors.affiliation: Yakult Central Institute for Microbiological Research, Tokyo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Imaoka
authors.forename: S
authors.initials: S
authors.lastname: Matsumoto
authors.forename: H
authors.initials: H
authors.lastname: Setoyama
authors.forename: Y
authors.initials: Y
authors.lastname: Okada
authors.forename: Y
authors.initials: Y
authors.lastname: Umesaki
mesh_terms: D000818:Animals; D001973:Bromodeoxyuridine; D002455:Cell Division; D004847:Epithelial Cells; D004848:Epithelium / Q000276:immunology; D005856:Germ-Free Life / Q000276:immunology*; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology*; D007421:Intestine, Small / Q000166:cytology / Q000276:immunology; D008213:Lymphocyte Activation; D016131:Lymphocyte Subsets / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis; D016196:S Phase
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; D001973:Bromodeoxyuridine