title: Tissue-specific distribution and age-dependent increase of human CD11b+ T cells.
abstract: Distribution of CD11b Ag, a member of the leukocyte integrin (beta 2 integrin) family, on human T cells is not well characterized. We investigated in this study the tissue distribution and age-related alteration of human CD11b+ T cells. Significant proportions of CD11b+ cells were found in T cells from adult peripheral blood (18-58 yr) (20%), liver (32%), and spleen (16%), but were rarely observed in those from thymus, lymph nodes, intraepithelial lymphocytes, lamina propria lymphocytes, and lung. In contrast, percentages of CD28+ T cells, a counter population of CD11b+ T cells, were highest in lymph nodes (91%), modest in intraepithelial lymphocytes (82%), lamina propria lymphocytes (77%), PBL (77%), spleen (73%) and lower in thymus (62%), lung (60%) and liver (56%). The CD11b+ T cells from peripheral blood gradually increased with age, whereas the CD28+ T cells showed an age-dependent decrease. Namely, the percentages of CD11b+ T cells were 6% in newborns (cord blood), 15% in young adults (18 to 22 yr), 25% in middleaged adults (45 to 58 yr), and 27% in aged adults (72 to 86 yr), whereas those of CD28+ T cells were 96%, 83%, 72%, and 71%, respectively. Proportions of CD11b+ T cells in TCR-gamma delta+ or CD8+ T cells were, respectively, higher than those in TCR-alpha beta+ or CD4+ T cells. Age-dependent increase of CD11b+ T cells in CD8+ T cells was more obvious than that of CD4+ T cells. Furthermore, CD11b+ CD28+ T cells increased in the peripheral blood only of aged adults. The percentage of CD11b+ CD28+ T cells in TCR-gamma delta+ T cells was highest in young adults (25%), whereas that in CD4+ T cells was highest in aged adults (15%). CD11b+ CD28+ T cells expressed much potent IFN-gamma, IL-2, and IL-4 at mRNA level than CD28+ CD11b- T cells or CD11b+ CD28- T cells, and had potential cytotoxic activity. Roles of CD11b+ T cells in vivo were discussed.
authors.affiliation: Department of Immunology, Kurume University School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hoshino
authors.forename: A
authors.initials: A
authors.lastname: Yamada
authors.forename: J
authors.initials: J
authors.lastname: Honda
authors.forename: Y
authors.initials: Y
authors.lastname: Imai
authors.forename: M
authors.initials: M
authors.lastname: Nakao
authors.forename: M
authors.initials: M
authors.lastname: Inoue
authors.forename: K
authors.initials: K
authors.lastname: Sagawa
authors.forename: M M
authors.initials: MM
authors.lastname: Yokoyama
authors.forename: K
authors.initials: K
authors.lastname: Oizumi
authors.forename: K
authors.initials: K
authors.lastname: Itoh
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D015703:Antigens, CD / Q000032:analysis; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D001483:Base Sequence; D018106:CD28 Antigens; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D016827:CD8 Antigens / Q000032:analysis; D016207:Cytokines / Q000235:genetics; D005260:Female; D005434:Flow Cytometry; D015870:Gene Expression; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016177:Macrophage-1 Antigen / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D012333:RNA, Messenger / Q000235:genetics; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D018106:CD28 Antigens; D016827:CD8 Antigens; D016207:Cytokines; D016177:Macrophage-1 Antigen; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D016692:Receptors, Antigen, T-Cell, gamma-delta