Replication of Vesicular Stomatitis Virus Facilitated in Nonpermissive Cells by Early Functions of Shope Fibroma Virus

Abstract

In serially cultured domestic rabbit kidney (DRK3) cells, vesicular stomatitis virus (VSV) alone was unable to replicate, inhibit synthesis of cellular DNA, or induce CPE [cytopathic effect]. When these cells were inoculated simultaneously with VSV plus Shope fibroma virus (SFV), both viruses replicated without apparent interference. This facilitation of VSV by SFV also occurred when these dually inoculated cells were treated with hydroxyurea at concentrations which inhibited production of infectious SFV by greater than 99% and synthesis of viral and cellular DNA with a buoyant density in CsCl of 1.69 g/cm3 by greater than 90%. Apparently, an early event in the replication of SFV, before viral DNA synthesis, converts DRK3 cells from a nonpermissive state, in which VSV alone is not able to induce CPE, to a permissive state that allows complete VSV replication.