title: Endogenous C-type viruses of BALB-c cells: frequencies of spontaneous and chemical induction.
abstract: A sensitive biological assay has been developed for studying the frequency of virus induction from mouse cells containing poorly infectious endogenous C-type viruses. A low spontaneous frequency of virus activation of one but not a second endogenous virus of BALB/c cells has been demonstrated. The resistance of BALB/c cells to superinfection by the more inducible virus appears to be absolute, whereas resistance to the other virus is only relative. Thus, the evidence indicates that the BALB/c cell exerts differential effects at two levels of regulation on the expression of its biologically distinguishable endogenous C-type viruses.
mesh_terms: D000818:Animals; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured / Q000382:microbiology*; D004305:Dose-Response Relationship, Drug; D017988:Gammaretrovirus / Q000254:growth & development* / Q000302:isolation & purification; D007065:Idoxuridine / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008815:Mice, Inbred Strains; D008937:Mitomycins / Q000494:pharmacology; D012190:Retroviridae / Q000254:growth & development* / Q000302:isolation & purification; D014762:Viral Interference; D014779:Virus Replication
chemical_list: D008937:Mitomycins; D007065:Idoxuridine