title: Predominant appearance of gamma/delta T lymphocytes in the liver of mice after birth.
abstract: gamma/delta T lymphocytes residing in the liver of mice were systematically characterized with respect to their age-related variation, phenotype and V gene segment usage of gamma/delta T cell receptor (TcR). Previous human and murine studies have shown that a high proportion of gamma/delta T cells reside in the liver and that such liver gamma/delta T cells have lymphoblastic morphology and can spontaneously proliferate in vitro. In the present study, a predominant appearance of gamma/delta T cells (up to 23% among CD3+ cells) in the liver was confirmed in 4-week old mice of various strains. gamma/delta T cells in the liver preferentially co-expressed CD8 antigens, whereas the vast majority of gamma/delta T cells in the spleen lacked the CD8 antigens. The identification of gamma/delta T cells in various lymphoid and non-lymphoid organs also revealed the liver to be one of the organs where gamma/delta T cell are most abundant. The level of such liver gamma/delta T cells showed a clear age-related variation. In the fetal stage and just after birth, gamma/delta T cells were not detectable in the liver (less than 0.2%). However, a significantly higher percentage of gamma/delta T cells among both the total population of mononuclear cells and CD3+ cells was detected in the liver of young 2- to 8-week-old mice; this percentage subsequently declined. As the total number of liver mononuclear cells increased in aged mice, the absolute number of liver gamma/delta T cells also increased as a function of age. V gene segment usage analysis by the polymerase chain reaction method demonstrated that V gamma 1 or V gamma 2/V delta 6 were preferentially used by liver gamma/delta T cells. The age-related increase of gamma/delta T cells was more prominent in the liver of athymic nude mice, and such gamma/delta T cells highly co-expressed the CD8 antigens and also utilized the V gamma 1 or V gamma 2/V delta 6 for gamma/delta Tcr. The predominant appearance of unique gamma/delta T cells in the liver, which was inversely related to the existence of the thymus, indicates that these gamma/delta T cells may differentiate extrathymically in the liver.
authors.affiliation: Department of Microbiology, Tohoku University School of Dentistry, Sendai and Department of Immunology, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ohteki
authors.forename: T
authors.initials: T
authors.lastname: Abo
authors.forename: S
authors.initials: S
authors.lastname: Seki
authors.forename: T
authors.initials: T
authors.lastname: Kobata
authors.forename: H
authors.initials: H
authors.lastname: Yagita
authors.forename: K
authors.initials: K
authors.lastname: Okumura
authors.forename: K
authors.initials: K
authors.lastname: Kumagai
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn / Q000276:immunology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D001483:Base Sequence; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens; D007694:Killer Cells, Natural / Q000276:immunology; D008099:Liver / Q000276:immunology*; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D011948:Receptors, Antigen, T-Cell / Q000032:analysis* / Q000235:genetics; D016692:Receptors, Antigen, T-Cell, gamma-delta; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D015704:CD4 Antigens; D016827:CD8 Antigens; D011948:Receptors, Antigen, T-Cell; D016692:Receptors, Antigen, T-Cell, gamma-delta