title: Imbalanced MHC class II molecule expression at surface of murine B cell lymphomas.
abstract: To study the role of class II MHC expression in mouse lymphomagenesis, we examined the cell surface expression of I-A/E antigens on 24 spontaneous or murine leukemia virus (MuLV)-induced mouse B10.A (I-Ak, I-Ek) B cell lymphomas. Two primary B10.A B cell lymphomas were observed with strong I-Ek expression but with only minimal cell surface I-Ak expression. Both tumors are readily transplantable in syngeneic mice, with maintenance of their I-A-, I-E+ phenotype. Strikingly, one I-A-, I-E+ B cell lymphoma contains a (11; 17) translocation with a breakpoint on chromosome 17 that is localized within or very close to the H-2 complex. DNA of both tumors contains normal restriction enzyme fragments of the A alpha and A beta genes. Northern blot analyses indicated that one I-A-, I-E+ tumor strongly expressed A alpha, E alpha, and E beta mRNAs but possessed only a weak expression of A beta mRNA. The other B cell lymphoma showed A beta, E alpha, and E beta mRNA expression but only minimal A alpha mRNA expression. In 11 primary B10.A B cell lymphomas with a normal I-A+, I-E+ phenotype, no imbalances in A alpha/A beta mRNA levels were observed. The implications of these findings for the role of class II MHC expression in mouse B cell lymphoma-genesis are discussed.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000235:genetics / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000276:immunology*; D007621:Karyotyping; D008223:Lymphoma / Q000235:genetics / Q000276:immunology*; D008285:Major Histocompatibility Complex; D008297:Male; D051379:Mice; D009368:Neoplasm Transplantation; D012333:RNA, Messenger / Q000235:genetics; D014178:Translocation, Genetic
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D004273:DNA, Neoplasm; D000949:Histocompatibility Antigens Class II; D012333:RNA, Messenger