title: Characterization and functional analysis of interferon-gamma-induced intercellular adhesion molecule-1 expression in human keratinocytes and A-431 cells.
abstract: Human intercellular adhesion molecule-1 (ICAM-1) is a cell-surface glycoprotein that serves as one of the major ligands for lymphocyte function-associated antigen-1 (LFA-1), a member of the integrin supergene family of adhesion molecules that is involved in cell-cell adhesion. Homotypic and heterotypic conjugate formation between leukocytes and between leukocytes and target cells via the LFA-1/ICAM-1 interaction has been demonstrated to be a critical event in numerous immunologic and inflammatory processes. While LFA-1 is expressed by all leukocytes, ICAM-1 is not normally expressed by all tissues with which leukocytes interact, but ICAM-1 may be induced de novo by various cytokines, including interferon-gamma (IFN-gamma). The constitutive and IFN-gamma-induced expression and function of ICAM-1 in human keratinocytes (HK) and A-431 cells in culture has been analyzed. While A-431 cells constitutively express ICAM-1 when assessed by northern blotting, by biosynthetic labeling and immunoprecipitation, and by flow cytometry, HK do not. When these two cell types are exposed to recombinant human (rh-) IFN-gamma at 1000 U/ml for 24 h, A-431 cells upregulate ICAM-1 and HK express ICAM-1 to an equal degree when assessed by these same parameters. Furthermore, in an in vitro adhesion assay, rh-IFN-gamma treatment of the HK or A-431 cells greatly increases the specific adherence of radiolabeled T cells to these cells. These data provide further evidence for the potential role of the regulated expression of ICAM-1 by keratinocytes in immunologic and inflammatory responses occurring in the skin.
authors.affiliation: Dermatology Branch, National Cancer Institutes of Health, Bethesda, Maryland 20892.
authors.forename: S W
authors.initials: SW
authors.lastname: Caughman
authors.forename: L J
authors.initials: LJ
authors.lastname: Li
authors.forename: K
authors.initials: K
authors.lastname: Degitz
mesh_terms: D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000235:genetics; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma / Q000494:pharmacology*; D015603:Keratinocytes / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins; D013601:T-Lymphocytes / Q000502:physiology; D015854:Up-Regulation
chemical_list: D015815:Cell Adhesion Molecules; D012333:RNA, Messenger; D011994:Recombinant Proteins; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma