title: Continuous propagation of radiation leukemia virus on a C57BL mouse-embryo fibroblast line, with attenuation of leukemogenic activity.
abstract: The radiation leukemia virus (RadLV), a murine leukemia virus derived from thymic lymphomas induced by x-irradiation in strain C57BL/Ka mice, has been successfully propagated in sustained high titer in vitro in a newly established line, BL-5, of C57BL/Ka mouse-embryo fibroblasts. In addition, the production of endogenous virus, presumed to be RadLV, has been induced and sustained through multiple serial passages after treatment of BL-5 cell cultures with 5-bromodeoxyuridine. The chronically RadLV-infected subline, designated BL-5 (RadLV), sheds virus into the supernatant culture fluids that is biologically active in vitro in the XC cell plaque assay, in interference assays for focus-formation by murine sarcoma virus, and in the intracellular induction of group-specific antigens detectable by immunofluorescence, but is apparently devoid of leukemogenic activity after intrathymic inoculation into neonatal or immunosuppressed C57BL/Ka mice. Although BL-5 cells exhibited morphological alterations suggestive of transformation in vitro and gave rise to fibrosarcomatous ascites tumors after intraperitoneal inoculation with C57BL/Ka mice, the chronically infected BL-5(RadLV) cells remained normal in morphology and failed to yield fibrosarcomas in vivo.
mesh_terms: D000818:Animals; D001973:Bromodeoxyuridine / Q000494:pharmacology; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D004622:Embryo, Mammalian; D005347:Fibroblasts; D005354:Fibrosarcoma / Q000382:microbiology; D009052:Leukemia Virus, Murine / Q000254:growth & development / Q000302:isolation & purification*; D007942:Leukemia, Experimental / Q000382:microbiology; D007953:Leukemia, Radiation-Induced / Q000382:microbiology; D008223:Lymphoma / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D010534:Peritoneal Neoplasms / Q000382:microbiology; D010948:Viral Plaque Assay; D014776:Virus Cultivation; D014779:Virus Replication / Q000187:drug effects
chemical_list: D001973:Bromodeoxyuridine