title: ICAM-3 (CD50) is expressed by human mast cells: induction of homotypic mast cell aggregation via ICAM-3.
abstract: Intercellular adhesion molecule-3 (ICAM-3, CD50), an adhesion receptor of the immunoglobulin superfamily, is suggested to play a key role in adhesive cellular interactions during the initial phase of an immune response. We here provide evidence that ICAM-3 is abundantly expressed by cells of the human mast cell line HMC-1 and, to a lower degree, by purified skin mast cells, as demonstrated by flow-cytometry, ELISA and RT-PCR. ICAM-3 immunoprecipitated from surface biotinylated HMC-1 cells migrates as a broad band of Mr 124,000 by Western blot analysis. We also demonstrate that monoclonal antibodies directed against ICAM-3 are capable of inducing rapid HMC-1 cell aggregation, the extent of which strongly depends on the epitope recognized by the mAb applied. Interestingly, although inhibitable by two of six mAbs against LFA-1, HMC-1 aggregation induced via ICAM-3 appears to be mediated by an adhesive pathway independent of LFA-1. Dermal mast cells are also aggregated with anti-ICAM-3 mAbs, a phenomenon which has not been described before for isolated tissue mast cells. However, this process displays slower kinetics, as compared to HMC-1 cells. That anti-ICAM-3 mAbs are able to mediate biological effects is further illustrated by their capability to increase stimulation-dependent release of the pro-inflammatory cytokines interleukin-6 (IL-6) and IL-8 from HMC-1 cells. Taken together, these results indicate that ICAM-3 is not only expressed by immature and mature human mast cells, but also possesses functional relevance and may therefore play a significant role in mast cell associated processes.
authors.affiliation: Department of Dermatology, Charité, Campus Virchow-Klinikum, Humboldt-Universität zu Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Babina
authors.forename: K
authors.initials: K
authors.lastname: Mammeri
authors.forename: B M
authors.initials: BM
authors.lastname: Henz
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD; D000943:Antigens, Differentiation; D015815:Cell Adhesion Molecules / Q000096:biosynthesis / Q000276:immunology / Q000502:physiology*; D002449:Cell Aggregation; D002460:Cell Line; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism; D008407:Mast Cells / Q000502:physiology*; D051379:Mice; D011233:Precipitin Tests; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D015815:Cell Adhesion Molecules; D003432:Cross-Linking Reagents; C483616:ICAM3 protein, human; D015850:Interleukin-6; D016209:Interleukin-8; D016169:Lymphocyte Function-Associated Antigen-1