Occurrence of Phenotypically Mixed Viruses in the Bryan High-Titer Strain of Rous Sarcoma Virus and RSV(RAV-1) Stocks 1

Summary

RSV stocks in common laboratory use, BH-RSV and its pseudotype designated as RSV (RAV-1), were examined to demonstrate occult xenogenetic RAV by using genetically different host cells and antisera specific to subgroups A and B avian tumor viruses. The virus stocks contained a phenotypically mixed virus, i.e., subgroup A RAV genome enveloped in subgroups B RAV protein coat. The virus replicated in C/A cells and yields the progeny of subgroup A RAV. The progeny replicated in C/O cells serially but not in C/A cells. The phenotypically mixed virus could not infect C/AB cells and was neutralized by an antiserum specific to subgroup B viruses. The possible origin and the significance of the virus were discussed.

The authors are indebted to Dr. William H. Murphy, the University of Michigan, for his helpful comments and criticisms during the preparation of this manuscript.