title: Characterization of lymphoid tumors induced by a recombinant murine retrovirus carrying the avian v-myc oncogene. Identification of novel (B-lymphoid) tumors in the thymus.
abstract: Lymphoid tumors induced by a recombinant murine retrovirus carrying the v-myc oncogene of avian MC29 virus were characterized. The Moloney murine leukemia virus myc oncogene (M-MuLV (myc], carried by an amphotropic MuLV helper, induced tumors in NIH Swiss and NFS/N mice after a relatively long latency (8 to 24 wk). Tumor masses appeared in the thymus, spleen, and lymph nodes. Flow cytometry of the tumor cells indicated that approximately 50% were positive for Thy 1.2. Most of these tumors also expressed one or more other cell surface markers of thymocytes and mature T cells (CD4, CD8). Southern blot hybridization revealed genomic rearrangements for the TCR beta genes. The TCR beta analysis suggested that the M-MuLV(myc)-induced Thy 1.2+ tumors were derived from somewhat less mature cells than tumors induced by M-MuLV, which is a classical non-acute retrovirus lacking an oncogene. The remainder of the M-MuLV(myc)-induced tumors were Thy 1.2-, but they were positive for Ly-5 (B220) and also for MAC-2. The Thy 1.2- tumors were characteristically located in the thymus. However, they were negative for TCR beta gene rearrangements. Some, but not all, of the Thy 1.2- tumors contained rearrangements for Ig genes. Additionally, they typically expressed mRNA specific for B but not for T cells. Thus, these thymic tumors had characteristics of the B cell lineage. Tumor transplantation experiments demonstrated that the Thy 1.2- tumor cells could reestablish in the thymus and spleen of irradiated hosts, and low level expression of the Thy 1 molecule was observed in the thymus but not the spleen on the first passage. After serial passage, one Thy 1- tumor altered its cell surface phenotype to Thy 1low B220-.
mesh_terms: D000818:Animals; D000954:Antigens, Surface; D001354:Avian Leukosis Virus / Q000235:genetics*; D001402:B-Lymphocytes; D004273:DNA, Neoplasm / Q000302:isolation & purification; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000209:etiology / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains; D008979:Moloney murine leukemia virus / Q000235:genetics*; D009368:Neoplasm Transplantation; D009857:Oncogenes; D010641:Phenotype; D012333:RNA, Messenger / Q000302:isolation & purification; D018800:Thy-1 Antigens; D013953:Thymus Neoplasms / Q000209:etiology / Q000235:genetics* / Q000276:immunology
chemical_list: D000954:Antigens, Surface; D004273:DNA, Neoplasm; D012333:RNA, Messenger; D018800:Thy-1 Antigens