title: Expression of costimulatory molecules on human retinoblastoma cells Y-79: functional expression of CD40 and B7H1.
abstract: OBJECTIVE
  To examine the expression of various costimulatory molecules on the human retinoblastoma cell line Y-79 and assess the functional roles of selected costimulatory molecules.
  
  
  METHODS
  Y-79 cells were incubated in the presence or absence of IFN-gamma, with or without irradiation (100 Gy). Expression of major histocompatibility complex (MHC) class I molecules, MHC class II, CD80, CD86, CD40, CD70, B7H1, B7DC, B7H2, OX40L, and 4-1BBL on Y-79 cells was measured by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometric analysis. The functional role of CD40-mediated interactions in modifying immune responses to Y-79 was assessed in vitro by using recombinant human CD40 ligand (rhCD40L). The costimulatory effect of B7H1-expressing IFN-gamma-treated Y-79 cells on proliferation of purified T cells was studied in Y-79/T-cell coculture experiments with a blocking anti-B7H1 monoclonal antibody (mAb).
  
  
  RESULTS
  CD40 and B7H2 were consistently detected on Y-79 cells by RT-PCR and flow cytometry. Cell surface expression of CD40 was upregulated on stimulation by IFN-gamma alone, radiation alone, and IFN-gamma combined with radiation. B7H1 expression was induced by IFN-gamma stimulation and increased further when irradiated Y-79 cells were stimulated by IFN-gamma. Treatment of Y-79 cells with rhCD40L enhanced cell surface expression of MHC class I and intercellular adhesion molecule (ICAM)-1 and also stimulated monocyte chemotactic protein (MCP)-1 production. Proliferative response of purified CD3+ T cells costimulated with IFN-gamma-stimulated Y-79 was significantly enhanced by the addition of anti-B7H1 mAb.
  
  
  CONCLUSIONS
  These results suggest that CD40 expressed on Y-79 plays an important role in augmenting antitumor immunity. In contrast, the expression of B7H1 on IFN-gamma-treated Y-79 cells contributes to the suppression of T cells. The dual effects of CD40 and B7H1 on Y-79 cells may contribute to positive or negative regulation of antitumor immune responses in human retinoblastoma.
authors.affiliation: Department of Ophthalmology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Usui
authors.forename: Youko
authors.initials: Y
authors.lastname: Okunuki
authors.forename: Takaaki
authors.initials: T
authors.lastname: Hattori
authors.forename: Masaru
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kezuka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Goto
authors.forename: Masahiko
authors.initials: M
authors.lastname: Usui
mesh_terms: D015703:Antigens, CD / Q000235:genetics*; D060890:B7-H1 Antigen; D019013:CD40 Antigens / Q000235:genetics*; D018932:Chemokine CCL2 / Q000235:genetics; D018920:Coculture Techniques; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D015395:Histocompatibility Antigens Class I / Q000235:genetics; D000949:Histocompatibility Antigens Class II / Q000235:genetics; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics; D007371:Interferon-gamma / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins; D019572:Retinal Neoplasms / Q000276:immunology*; D012175:Retinoblastoma / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000276:immunology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000528:radiation effects; D015854:Up-Regulation
chemical_list: D015703:Antigens, CD; D060890:B7-H1 Antigen; C111835:CCL2 protein, human; C423236:CD274 protein, human; D019013:CD40 Antigens; D018932:Chemokine CCL2; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D012333:RNA, Messenger; D011994:Recombinant Proteins; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma