title: Differential regulation of HLA-DR expression and antigen presentation in Toxoplasma gondii-infected melanoma cells by interleukin 6 and interferon gamma.
abstract: CD4+ cytotoxic T lymphocytes (CTL) clones, YT-4 and YT-9, specific for Toxoplasma gondii (T. gondii)-infected melanoma SK-MEL 28 (P36), were generated from the peripheral blood lymphocytes (PBL) of a patient with chronic toxoplasmosis. These CTL clones were shown to secrete significant amounts of interleukin 6 (IL-6) and interferon gamma (IFN-gamma) upon antigen (Ag)-specific stimulation. Downregulation of human leukocyte antigen (HLA)-DR surface expression and HLA-DR mRNA levels in P36 cells were observed when P36 cells were infected with T. gondii. Such downregulated HLA-DR expressions of T. gondii-infected P36 cells were upregulated by treatment with both recombinant IL-6 (rIL-6) and recombinant IFN-gamma (rIFN-gamma). The antigen-presenting ability of T. gondii-infected P36 cells to T. gondii-infected cell-specific CTL was enhanced by rIFN-gamma but not by rIL-6. The present study reveals the existence of differential regulation of HLA-DR expression and Ag presentation in T. gondii-infected melanoma cells by IL-6 and IFN-gamma.
authors.affiliation: Department of Medical Zoology, Nagasaki University School of Medicine, Japan.
authors.forename: T H
authors.initials: TH
authors.lastname: Yang
authors.forename: F
authors.initials: F
authors.lastname: Aosai
authors.forename: K
authors.initials: K
authors.lastname: Norose
authors.forename: M
authors.initials: M
authors.lastname: Ueda
authors.forename: A
authors.initials: A
authors.lastname: Yano
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002999:Clone Cells; D016207:Cytokines / Q000276:immunology; D006684:HLA-DR Antigens / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology*; D015850:Interleukin-6 / Q000276:immunology*; D008545:Melanoma; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology / Q000276:immunology*; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000097:blood / Q000276:immunology*; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
chemical_list: D016207:Cytokines; D006684:HLA-DR Antigens; D015850:Interleukin-6; D007371:Interferon-gamma