title: Natural killer cells play a role in MHC class I in vivo induction in tumor cells that are MHC negative in vitro.
abstract: The natural killer (NK) cell is one of the key cells in discriminating major histocompatibility complex (MHC) negative 'missing-self' target tumor cells, and interleukin 2 (IL-2) treatment was effective in inducing NK cell activation. In this study, we tried to clarify how poorly-immunogenic murine B16 melanoma could be discriminated in vivo by creating an IL-2 cDNA-transduced immunogene therapy model (B16/IL-2). In vitro study showed that IL-2 introduction did not induce MHC class I. However, immune cells depleted total tumor digest, which consisted of 90% anti-melanoma MM2-9B6-positive cells that revealed B16/IL-2 strongly, and control tumor cells (B16/mock) partially expressed MHC class I in vivo. In the B16/IL-2 model, NK cell infiltration was 10 times higher than B16/mock (7.6 versus 0.73, p=0.017). In addition, the cell surface of CD69-expressing NK cell population was increased in B16/IL-2, and the interferon gamma (IFNgamma) message level in NK cells was significantly increased in B16/IL-2 (p=0.0359). Interestingly, NK cell depletion in vivo completely abolished MHC class I expression on B16/mock, and decreased MHC class I expression and T-cell infiltration in B16/IL-2. These data suggest that NK cells are not only important for missing-self recognition, but are also crucial for induction of tumor cell MHC molecule expression and play an important role in helping acquired immunity to recognize tumor cells.
authors.affiliation: Division of Immunoregulation, Section of Disease Control, Institute for Genetic Medicine, Hokkaido University, Sapporo, Hokkaido, Japan.
authors.forename: Mika
authors.initials: M
authors.lastname: Kijima
authors.forename: Masanao
authors.initials: M
authors.lastname: Saio
authors.forename: Guan-Feng
authors.initials: GF
authors.lastname: Oyang
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Suwa
authors.forename: Rumiko
authors.initials: R
authors.lastname: Miyauchi
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kojima
authors.forename: Hisashi
authors.initials: H
authors.lastname: Imai
authors.forename: Jiro
authors.initials: J
authors.lastname: Nakagawa
authors.forename: Kenichi
authors.initials: K
authors.lastname: Nonaka
authors.forename: Naoki
authors.initials: N
authors.lastname: Umemura
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishimura
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takami
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic; D005805:Genes, MHC Class I; D006680:HLA Antigens / Q000096:biosynthesis*; D007371:Interferon-gamma / Q000276:immunology; D007376:Interleukin-2 / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000276:immunology*; D008545:Melanoma / Q000235:genetics* / Q000276:immunology* / Q000662:veterinary; D051379:Mice; D012878:Skin Neoplasms / Q000235:genetics* / Q000276:immunology* / Q000662:veterinary; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D006680:HLA Antigens; D007376:Interleukin-2; D007371:Interferon-gamma