title: Expression and functional effects of Eph receptor tyrosine kinase A family members on Langerhans like dendritic cells.
abstract: BACKGROUND
  The Eph receptors are the largest receptor tyrosine kinase family. Several family members are expressed in hematopoietic cells. Previously, the expression of a member of this family, EphA2, was identified on dendritic like cells in tonsils. We therefore specifically examined the expression of EphA2 on in vitro generated dendritic cells.
  
  
  RESULTS
  In this study, expression of the EphA2 receptor was identified on in vitro generated Langerhans like dendritic cells compared to in vitro generated dendritic cells. We show that ligand induced engagement of the EphA2 receptor leads to receptor autophosphorylation indicating a functional receptor signaling pathway in these cells. We also observe phosphorylation and dephosphorylation of distinct proteins following ligand activation of EphA receptors. In co-stimulation assays, receptor-ligand interaction reduces the capacity of the Langerhans like dendritic cells to stimulate resting CD4+ T cells.
  
  
  CONCLUSIONS
  Engagement of EphA receptor tyrosine kinases on Langerhans like dendritic cells induces signaling as shown by tyrosine phosphorylation and dephosphorylation of distinct proteins. Furthermore this engagement renders the cells less capable of stimulating CD4+ T cells.
authors.affiliation: Department of Immunology, The Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway. else.munthe@labmed.uio.no
authors.forename: Else
authors.initials: E
authors.lastname: Munthe
authors.forename: Eivind Farmen
authors.initials: EF
authors.lastname: Finne
authors.forename: Hans-Christian
authors.initials: HC
authors.lastname: Aasheim
mesh_terms: D000954:Antigens, Surface / Q000096:biosynthesis; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology; D015815:Cell Adhesion Molecules / Q000096:biosynthesis; D002455:Cell Division / Q000502:physiology; D002460:Cell Line; D003432:Cross-Linking Reagents / Q000494:pharmacology; D016207:Cytokines / Q000502:physiology; D003713:Dendritic Cells / Q000737:chemistry* / Q000378:metabolism*; D036383:Ephrin-A2 / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics*; D007801:Langerhans Cells / Q000737:chemistry* / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000502:physiology; D036104:Receptor, EphA2 / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D036081:Receptors, Eph Family / Q000235:genetics* / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D016176:T-Lymphocyte Subsets / Q000502:physiology; D013601:T-Lymphocytes / Q000378:metabolism; D018417:Th1 Cells / Q000502:physiology; D018418:Th2 Cells / Q000502:physiology
chemical_list: D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D003432:Cross-Linking Reagents; D016207:Cytokines; D036383:Ephrin-A2; D036104:Receptor, EphA2; D036081:Receptors, Eph Family