title: Ultrastructure of murine tumour cell lines defective in MHC class I expression before and after interferon-gamma treatment.
abstract: Two tumour cell clones, 6D1 and 4C2 cells, which are defective both in the major histocompatibility gene complex (MHC) class I expression and in the endogenous antigen presentation, are recovered with interferon (IFN)-gamma treatment. The present study describes the ultrastructure of these cells by using scanning and transmission electron microscopy in relation to the effect of IFN-gamma treatment. The general morphology of these cells was found to be similar to each other and comparable to that of a tumour cell clone, 4A1 cells, of the same origin, normal in MHC class I expression; they exhibited a fibroblast-like appearance and had many blebs on all the cell surfaces, with desmosome-like junctions between cells. On IFN-gamma treatment, surface fine blebs appeared less, and mitochondria became more densely stained. Expression of MHC class I molecules on the cell surface was much higher in the IFN-gamma treated 6D1 and 4C2 cells than in untreated cells, when estimated by immunoelectron microscopy. The addition of an epitope peptide to these cells did not enhance the class I expression, which differed from other antigen presentation-defective cells such as RMA-S cells, nor change the cell surface morphology.
authors.affiliation: Department of Virology and Immunology, Oska University of Pharmaceutical Sciences, Japan. nz6t-hsk@asahi-net.or.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Hosaka
authors.forename: K
authors.initials: K
authors.lastname: Taguchi
authors.forename: T
authors.initials: T
authors.lastname: Iwamoto
authors.forename: K
authors.initials: K
authors.lastname: Kuroda
authors.forename: H
authors.initials: H
authors.lastname: Tsuruoka
authors.forename: H
authors.initials: H
authors.lastname: Xu
authors.forename: T
authors.initials: T
authors.lastname: Hamaoka
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D000970:Antineoplastic Agents / Q000494:pharmacology*; D048429:Cell Size / Q000187:drug effects; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000276:immunology*; D007371:Interferon-gamma / Q000494:pharmacology*; D051379:Mice; D008854:Microscopy, Electron; D009374:Neoplasms, Experimental / Q000235:genetics / Q000276:immunology* / Q000648:ultrastructure*; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D015395:Histocompatibility Antigens Class I; D007371:Interferon-gamma