title: Intercellular adhesion molecule-3 (CD50) on human epidermal Langerhans cells participates in T-cell activation.
abstract: Three different intercellular adhesion molecules (ICAMs) have been identified acting as ligand for counter-receptor leukocyte-function-associated antigen-1 (LFA-1) (CD11a/CD18). We have recently shown that ICAM-1 (CD54) is present on cultured human epidermal Langerhans cells but not on freshly isolated Langerhans cells, and that this molecule participates in the generation of an antigen-specific T-cell response. ICAM-2 (CD102) was not involved because this molecule is expressed by neither fresh nor cultured Langerhans cells. In this study, the presence of ICAM-3 (CD50) on Langerhans cells was examined. Flow cytofluorometric analysis demonstrated that ICAM-3 is strongly displayed by fresh Langerhans cells, and daily determinations showed that the level of this trypsin-resistant molecule remained nearly unchanged during in vitro culture for up to 4 d, indicating that Langerhans cells constitutively express this molecule. Analysis of RNA extracted from purified cultured Langerhans cells by means of reverse transcriptase-polymerase chain reaction demonstrated the presence of mRNA specific for ICAM-3. Antigen-specific T-cell responses triggered by Langerhans cells were dose-dependently inhibited by anti-ICAM-3 if the antibody was added within the first 16 h of T-cell stimulation. Simultaneous addition of anti-ICAM-1 and anti-ICAM-3 synergistically inhibited T-cell responses, although a total block was never achieved. Pretreatment of Langerhans cells with anti-ICAM-3 resulted in a reduced T-cell response, whereas pretreatment of T cells did not. These results suggest that ICAM-3 on Langerhans cells, like ICAM-1, is functionally involved in the initiation of antigen-specific activation of T cells, but the expression of these two ICAMs on Langerhans cells is differently regulated.
authors.affiliation: Department of Dermatology, Academic Medical Center, University of Amsterdam, The Netherlands.
authors.forename: M B
authors.initials: MB
authors.lastname: Teunissen
authors.forename: C W
authors.initials: CW
authors.lastname: Koomen
authors.forename: J D
authors.initials: JD
authors.lastname: Bos
mesh_terms: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured; D000939:Epitopes; D006801:Humans; D007801:Langerhans Cells / Q000737:chemistry*; D008213:Lymphocyte Activation; D012333:RNA, Messenger / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology*; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D015815:Cell Adhesion Molecules; D000939:Epitopes; C483616:ICAM3 protein, human; D012333:RNA, Messenger