title: Serological analysis of BALB/C methylcholanthrene sarcoma Meth A by SEREX: identification of a cancer/testis antigen.
abstract: Antigens of BALB/c methylcholanthrene-induced fibrosarcoma Meth A recognized by the host humoral immune response were investigated by serological analysis of antigens by recombinant expression cloning (SEREX). Immunoscreening a cDNA library from Meth A (Kgamma) cells (Meth A retrovirally transfected with murine IFN-gamma cDNA) with sera from BALB/c mice growing parental Meth A transplants identified 10 antigens. One of them, OY-MS-4, showed characteristics of a cancer/testis (CT) antigen. Nucleotide sequence analysis revealed that OY-MS-4 was identical to a mouse placenta and embryonic expression gene (pem) known to be selectively expressed during embryogenesis and in transformed cell lines. In adult mice, expression of OY-MS-4 was restricted to testis and placenta. Four of 6 methylcholanthrene-induced fibrosarcomas in BALB/c mice showed strong expression of OY-MS-4. In 6 T-cell leukemias, only a dimethylbenzanthracene-induced leukemia, EL4 (C57BL), showed strong expression. Two other tumors, A20.2J and P815, induced by ethylnitrosourea and methylcholanthrene, respectively, also strongly expressed OY-MS-4. The other 9 gene products identified in Meth A by SEREX were expressed in all 15 tumors tested and in a range of normal tissues. Sequence analysis of cDNA inserts coding for the SEREX-defined antigens showed no evidence of mutation. Despite the expression of OY-MS-1-10 antigens in methylcholanthrene sarcomas other than Meth A, no antibody was detected in the sera of mice bearing these other sarcomas. The basis for the unique immunogenicity of OY-MS-1-10 presented by Meth A, but not by other syngeneic tumors expressing these gene products, is unknown.
authors.affiliation: Department of Immunology, Okayama University Medical School, Okayama, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ono
authors.forename: S
authors.initials: S
authors.lastname: Sato
authors.forename: N
authors.initials: N
authors.lastname: Kimura
authors.forename: M
authors.initials: M
authors.lastname: Tanaka
authors.forename: A
authors.initials: A
authors.lastname: Shibuya
authors.forename: L J
authors.initials: LJ
authors.lastname: Old
authors.forename: E
authors.initials: E
authors.lastname: Nakayama
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000912:Antibodies, Neoplasm / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D000951:Antigens, Neoplasm / Q000032:analysis* / Q000235:genetics; D002273:Carcinogens; D018076:DNA, Complementary / Q000235:genetics; D008297:Male; D008748:Methylcholanthrene; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012513:Sarcoma, Experimental / Q000139:chemically induced / Q000276:immunology*; D012698:Serologic Tests / Q000379:methods*; D014407:Tumor Cells, Cultured / Q000276:immunology
chemical_list: D000912:Antibodies, Neoplasm; D000951:Antigens, Neoplasm; D002273:Carcinogens; D018076:DNA, Complementary; D012333:RNA, Messenger; D008748:Methylcholanthrene