title: An unique CD4+CD8+ intestinal intraepithelial lymphocyte specific for DnaK (Escherichia coli HSP70) may be selected by intestinal microflora of rats.
abstract: We have previously shown an age-associated increase in unique CD4+CD8+ intestinal intraepithelial lymphocytes (i-IEL) in rats. To elucidate the potential causes of the increase in CD4+CD8+ i-IEL with age, we analyzed the specificity of the CD4+CD8+ i-IEL and influence of intestinal microflora on the increase in this subset in aged rats. The purified CD4+CD8+ i-IEL proliferated in response to DnaK [Escherichia coli (E. coli) HSP70] in the presence of mitomycin-c (MMC)-treated syngeneic spleen cells. The proportion of CD4+CD8+ T cells in whole i-IEL were significantly increased in aged rats fed commercial (CL-2) diet but not in those fed home-made (purified) diet under conventional condition. No CD4+CD8+ i-IEL were detected in aged rats under germfree condition, irrespective of diet feeding. A larger number of Enterobacteriaceae, especially E. coli, were detected in the intestinal contents and feces from aged rats with CD4+CD8+ i-IEL compared with those from aged rats fed without CD4+CD8+ i-IEL. The unique CD4+CD8+ i-IEL population specific for E. coli HSP may be associated with long term exposure to intestinal E. coli in aged rats.
authors.affiliation: Laboratory of Host Defense and Germfree Life, Nagoya University School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kimura
authors.forename: T
authors.initials: T
authors.lastname: Sakai
authors.forename: M
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Y
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.forename: M
authors.initials: M
authors.lastname: Yuuki
authors.forename: T
authors.initials: T
authors.lastname: Takada
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshikai
mesh_terms: D000375:Aging / Q000276:immunology; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D015704:CD4 Antigens / Q000032:analysis*; D016827:CD8 Antigens / Q000032:analysis*; D002454:Cell Differentiation / Q000276:immunology; D004032:Diet; D004848:Epithelium / Q000276:immunology / Q000382:microbiology; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins / Q000276:immunology*; D007413:Intestinal Mucosa / Q000276:immunology* / Q000382:microbiology*; D008213:Lymphocyte Activation; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000382:microbiology
chemical_list: D015704:CD4 Antigens; D016827:CD8 Antigens; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; C063842:dnaK protein, E coli