title: In vitro production and titration assays of B-tropic retroviruses isolated from C57BL mouse tumors induced by radiation leukemia virus (RadLV-Rs): effect of dexamethasone.
abstract: The effect of dexamethasone (DXM) on the replication and titration assays of B-ecotropic radiation leukemia virus (RadLV-Rs) isolates was examined. The drug was shown to enhance in vitro virus release by otherwise low producer permissive cells. DXM also stimulated infectivity and focus formation in murine S+L--permissive cells and shortened the time-appearance of virus-induced foci. In contrast to foci observed in nontreated cultures, which are generally abortive and composed of only a few morphologically transformed cells, those obtained with DXM were comparable to those induced by ecotropic retroviruses with a potent helper activity for murine sarcoma virus. In addition, DXM increased virus-induced XC cell fusion. These fundamental data allowed a more abundant in vitro production of the B-ecotropic RadLV-Rs virus isolates as well as precise infectivity titration assays.
mesh_terms: D000818:Animals; D002459:Cell Fusion / Q000187:drug effects; D002460:Cell Line; D002472:Cell Transformation, Viral; D003588:Cytopathogenic Effect, Viral; D003907:Dexamethasone / Q000494:pharmacology*; D009052:Leukemia Virus, Murine / Q000254:growth & development*; D007942:Leukemia, Experimental / Q000382:microbiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D014776:Virus Cultivation / Q000379:methods*; D014779:Virus Replication / Q000187:drug effects
chemical_list: D003907:Dexamethasone