title: MHC class II antigen presentation pathway in murine tumours: tumour evasion from immunosurveillance?
abstract: Qualitative differences in the MHC class II antigen processing and presentation pathway may be instrumental in shaping the CD4+ T cell response directed against tumour cells. Efficient loading of many MHC class II alleles with peptides requires the assistance of H2-M, a heterodimeric MHC class II-like molecule. In contrast to the HLA-DM region in humans, the beta-chain locus is duplicated in mouse, with the H2-Mb1 (Mb1beta-chain distal to H2-Mb2 (Mb2) and the H2-Ma (Ma) alpha-chain gene). Here, we show that murine MHC class II and H2-M genes are coordinately regulated in murine tumour cell lines by T helper cell 1 (IFN-gamma) and T helper cell 2 (IL-4 or IL-10) cytokines in the presence of the MHC class II-specific transactivator CIITA as determined by mRNA expression and Western blot analysis. Furthermore, Malphabeta1 and Malphabeta2 heterodimers are differentially expressed in murine tumour cell lines of different histology. Both H2-M isoforms promote equally processing and presentation of native protein antigens to H2-A(d)- and H2-E(d)-restricted CD4+ T cells. Murine tumour cell lines could be divided into three groups: constitutive MHC class II and CIITA expression; inducible MHC class II and CIITA expression upon IFN-gamma-treatment; and lack of constitutive and IFN-gamma-inducible MHC class II and CIITA expression. These differences may impact on CD4+ T cell recognition of cancer cells in murine tumour models.
authors.affiliation: Department of Medical Microbiology, Johannes Gutenberg University, Mainz, D-55101, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Walter
authors.forename: K
authors.initials: K
authors.lastname: Lingnau
authors.forename: E
authors.initials: E
authors.lastname: Schmitt
authors.forename: M
authors.initials: M
authors.lastname: Loos
authors.forename: M J
authors.initials: MJ
authors.lastname: Maeurer
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D015153:Blotting, Western; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D019281:Dimerization; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006681:HLA-D Antigens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000276:immunology*; D007371:Interferon-gamma / Q000494:pharmacology; D016753:Interleukin-10 / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009687:Nuclear Proteins; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators / Q000235:genetics; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000276:immunology / Q000378:metabolism
chemical_list: C416189:H2-M antigens; D006681:HLA-D Antigens; C084245:HLA-DM antigens; D000949:Histocompatibility Antigens Class II; C083728:MHC class II transactivator protein; D009687:Nuclear Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D015534:Trans-Activators; D016753:Interleukin-10; D015847:Interleukin-4; D007371:Interferon-gamma