title: Gamma/delta intraepithelial lymphocytes in the mouse small intestine.
abstract: Although many studies of intraepithelial lymphocytes (IELs) have been reported, most of them have focused on αβ-IELs; little attention has been paid to γδ-IELs. The function of γδ-IELs remains largely unclear. In this article, we briefly review a number of reports on γδ-IELs, especially those in the small intestine, along with our recent studies. We found that γδ-IELs are the most abundant (comprising >70 % of the) IELs in the duodenum and the jejunum, implying that it is absolutely necessary to investigate the function(s) of γδ-IELs when attempting to delineate the in vivo defense system of the small intestine. Intraperitoneal injection of anti-CD3 mAb stimulated the γδ-IELs and caused rapid degranulation of them. Granzyme B released from their granules induced DNA fragmentation of duodenal and jejunal epithelial cells (paracrine) and of the IELs themselves (autocrine). However, perforin (Pfn) was not detected, and DNA fragmentation was induced even in Pfn-knockout mice; our system was therefore found to present a novel type of in vivo Pfn-independent DNA fragmentation. We can therefore consider γδ-IELs to be a novel type of large granular lymphocyte without Pfn. Fragmented DNA was repaired in the cells, indicating that DNA fragmentation alone cannot be regarded as an unambiguous marker of cell death or apoptosis. Finally, since the response was so rapid and achieved without the need for accessory cells, it seems that γδ-IELs respond readily to various stimuli, are activated only once, and die 2-3 days after activation in situ without leaving their site. Taken together, these results suggest that γδ-IELs are not involved in the recognition of specific antigen(s) and are not involved in the resulting specific killing or exclusion of the relevant antigen(s).
authors.affiliation: Division of Immunology and Embryology, Department of Cell Biology, Tohoku University School of Medicine, Sendai, 980-8575, Japan.|Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Ogata
authors.affiliation: Division of Immunology and Embryology, Department of Cell Biology, Tohoku University School of Medicine, Sendai, 980-8575, Japan. ts_itoh@tfu-mail.tfu.ac.jp.|Department of Health Services Management, Faculty of Health Sciences, Tohoku Fukushi University, 1-19-1 Kunimi, Aoba-ku, Sendai, 981-8523, Japan. ts_itoh@tfu-mail.tfu.ac.jp.
authors.forename: Tsunetoshi
authors.initials: T
authors.lastname: Itoh
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology; D016923:Cell Death; D015550:Cell Degranulation; D053938:DNA Fragmentation; D004847:Epithelial Cells / Q000276:immunology; D053804:Granzymes; D007421:Intestine, Small / Q000166:cytology* / Q000276:immunology; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D051379:Mice / Q000033:anatomy & histology*; D054353:Perforin
chemical_list: D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D054353:Perforin; D053804:Granzymes
keywords: DNA fragmentation; Immunohistology; Intraepithelial lymphocyte (IEL); Mouse; Small intestine