title: U5 monoclonal antibody identifies a novel lymphocyte surface antigen preferentially expressed in human circulating natural killer cells with high cytotoxic activity.
abstract: U5 monoclonal antibody (mAb), developed against Japanese monkey lymphocytes, identified a glycoprotein of 32 000 MW that is expressed in a subset of human circulating natural killer (NK) cells. The distribution of U5 molecules was restricted among CD16+ cells, and U5 antigen was preferentially expressed in the CD38+ subset. U5+ CD16+ CD56+ cells were highly active on NK assay against K562 target cells. Variations in cytolytic activities and mRNA expression of perforin, granzyme B and Fas ligand (FasL) were observed in U5- CD16+ CD56+ cells depending on the donor. We found that in some donors, a phenotypically mature (CD16+ CD56+) but functionally immature subset was present in the peripheral circulation. The U5- CD16+ CD56+ cells of some donors exhibited negligible cytolytic activity with no detectable expression of the above mRNAs, whereas those of the other donors had a significant but lower cytolytic activity with a reduced expression of granzyme B mRNA as compared with those of U5+ CD16+ CD56+ cells. Concanavalin A (Con A) stimulation induced an expression of U5 antigen in U5- CD16+ CD56+ cells accompanied by an up-regulation of granzyme B mRNA expression. These findings suggest that U5 antigen may be a novel molecule involved in the maturation or differentiation of human circulating NK cells.
authors.affiliation: Institute of Basic Medical Sciences, University of Tsukuba, Tennodai, Tsukuba, Ibaraki, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ikura
authors.forename: K
authors.initials: K
authors.lastname: Terao
authors.forename: I
authors.initials: I
authors.lastname: Matsuzaki
authors.forename: M
authors.initials: M
authors.lastname: Inoue-Murayama
authors.forename: Y
authors.initials: Y
authors.lastname: Murayama
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD / Q000097:blood; D000954:Antigens, Surface / Q000097:blood*; D018929:Cell Culture Techniques; D003208:Concanavalin A / Q000276:immunology; D016207:Cytokines / Q000276:immunology; D003602:Cytotoxicity, Immunologic / Q000276:immunology*; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D016131:Lymphocyte Subsets / Q000276:immunology*; D008297:Male; D008562:Membrane Glycoproteins / Q000097:blood*
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000954:Antigens, Surface; D016207:Cytokines; D008562:Membrane Glycoproteins; D003208:Concanavalin A