title: Comparative studies of decay-accelerating factor and HLA-DR within the CD8-brightly positive population.
abstract: Decay-accelerating factor (DAF) is a membrane protein that inhibits C3 convertase activity of autologous complement at the cell surface. We found that DAF+ cells and DAF- (DAFlow, if any) cells are clearly separated from each other among CD8-brightly positive (CD8bright) cells. Using three-color fluorescence flow cytometry, we found that whereas the CD8bright DAF- population express HLA-DR (class II major histocompatibility complex antigens, and an activated T cell marker), the CD8bright DAF+ population does not. Therefore, among the CD8bright T cells, DAF and HLA-DR are mutually exclusive. In addition, the CD8bright DAF+ population proliferates in the presence of recombinant interleukin 2 (rIL2) while the CD8bright DAF- population does not. After a 4-day cultivation of peripheral blood lymphocytes in the presence of rIL2, expression of HLA-DR increased in the CD8bright DAF- population and expression of IL 2Rp55 (alpha chain, the receptor for IL2, and a marker of T cell activation) occurred in the CD8bright DAF+ population. Furthermore, C3 deposition occurred in the CD8bright HLA-DR+ population which lacks DAF when lymphocytes, that had been cultured for 3 days in the presence of rIL2, were incubated with fresh autologous serum. This result suggests that the absence of DAF on CD8bright HLA-DR+ T cells might play a role in permitting complement reaction on the cells in vivo and may be related to the regulation of T cell activation.
authors.affiliation: First Department of Surgery, Fukuoka University School of Medicine, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Tomita
authors.forename: N
authors.initials: N
authors.lastname: Okada
authors.forename: H
authors.initials: H
authors.lastname: Okada
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000032:analysis*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D018958:CD55 Antigens; D016827:CD8 Antigens; D003176:Complement C3 / Q000378:metabolism; D003169:Complement Inactivator Proteins / Q000032:analysis*; D006684:HLA-DR Antigens / Q000032:analysis*; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D008213:Lymphocyte Activation; D008565:Membrane Proteins / Q000032:analysis*; D011994:Recombinant Proteins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D018958:CD55 Antigens; D016827:CD8 Antigens; D003176:Complement C3; D003169:Complement Inactivator Proteins; D006684:HLA-DR Antigens; D007376:Interleukin-2; D008565:Membrane Proteins; D011994:Recombinant Proteins