title: Enhanced ICAM-1-dependent adhesion of myelomonocytic cells expressing increased levels of beta 2-integrins and CD43.
abstract: Interaction of ICAM-1 and its ligands plays an important role in the leukocyte binding to endothelium. The best characterized ICAM-ligands belong to the family of beta 2-integrins (CD11/CD18), but recently it has been suggested that CD43, a molecule with no structural resemblance to integrins binds ICAM-1 also. On the leukocytes the main regulatory pathway for ICAM-mediated binding is believed to be a short-term regulation of the avidity of CD11/CD18. In this study the authors investigated whether a quantitative increase in the surface expression of ICAM-ligands also can lead to enhanced binding to purified ICAM-1. PMA-treatment differentiates myelomonocytic cell lines into macrophages with a concomitant increase in the surface expression and mRNA-levels of the beta 2-integrin alpha- and beta-chains as well as that of CD43, another ICAM-ligand. The binding of the PMA-treated THP-1 cells to ICAM-1 was increased simultaneously compared to non-treated cells. The binding was blocked completely with antibodies to CD18 and ICAM-1. It is concluded that in addition to the transient qualitative regulation, a long-term quantitative regulation of ICAM-1 ligands also plays a role in increasing the adhesiveness of myelomonocytic cells. This may be relevant in chronic inflammation episodes.
authors.affiliation: Department of Bacteriology and Immunology, University of Helsinki, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Tiisala
authors.forename: M L
authors.initials: ML
authors.lastname: Majuri
authors.forename: O
authors.initials: O
authors.lastname: Carpén
authors.forename: R
authors.initials: R
authors.lastname: Renkonen
mesh_terms: D015703:Antigens, CD / Q000235:genetics / Q000502:physiology; D000954:Antigens, Surface / Q000502:physiology; D018845:CD11 Antigens; D018821:CD18 Antigens; D002448:Cell Adhesion / Q000187:drug effects*; D015815:Cell Adhesion Molecules / Q000494:pharmacology*; D006801:Humans; D016023:Integrins / Q000032:analysis*; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D051917:Leukosialin; D012333:RNA, Messenger / Q000032:analysis; D012795:Sialoglycoproteins / Q000032:analysis* / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000737:chemistry / Q000166:cytology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D015703:Antigens, CD; D000954:Antigens, Surface; D018845:CD11 Antigens; D018821:CD18 Antigens; D015815:Cell Adhesion Molecules; D016023:Integrins; D007375:Interleukin-1; D051917:Leukosialin; D012333:RNA, Messenger; C465014:SPN protein, human; D012795:Sialoglycoproteins; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma; D013755:Tetradecanoylphorbol Acetate