title: Persistent infection of BHK21/WI-2 cells with rubella virus and characterization of rubella variants.
abstract: Persistently infected cell lines of BHK21/WI-2 cells have been established by infection with the wild type rubella virus strain M-33. These cell lines, BHK-MP1 and BHK-MP2, showed immunity-like resistance to superinfection with M-33 virus at both 34 degrees and 39.5 degrees C. They also showed intrinsic interference with the replication of Newcastle Disease Virus at 34 degrees C but not at 39.5 degrees C. They released a small number of infectious virus particles which were temperature sensitive variants, being able to form plaques at 34 degrees C, but not at 39.5 degrees C on BHK21/WI-2 and on its derivative, BSR. When BHK-MP1 cells were cultured at 34 degrees C in growth medium containing 10--20 microgram/ml of 5-bromodeoxyuridine (BudR) there was a 5- to 10-fold increase in infectious virus in the medium as compared with the untreated controls. Mitomycin C (0.5 microgram/ml) treatment for 7 hours likewise stimulated the release of virus from these cells. The enhancement of viral release by BudR was completely blocked by pretreatment with actinomycin D (5 microgram/ml) for 3 hours prior to BudR treatment. Since the variant can be induced by these prophage inducers and inhibited by actinomycin D it is suggested that the viral genome is converted to a DNA provirus which is analogous to the lysogenic state of bacteriophage.
mesh_terms: D000818:Animals; D001973:Bromodeoxyuridine / Q000494:pharmacology; D002460:Cell Line; D006224:Cricetinae; D003609:Dactinomycin / Q000494:pharmacology; D014644:Genetic Variation; D008937:Mitomycins / Q000494:pharmacology; D009522:Newcastle disease virus / Q000254:growth & development; D012412:Rubella virus / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D013696:Temperature; D014762:Viral Interference; D014779:Virus Replication / Q000187:drug effects
chemical_list: D008937:Mitomycins; D003609:Dactinomycin; D001973:Bromodeoxyuridine