Demonstration of Double-Stranded Ribonucleic Acid in Concentrates of RNA Viruses

Summary Nucleic acid preparations from unpurified concentrates of Newcastle disease virus, Sindbis virus and Semliki Forest virus were found to contain up to 2% double-stranded RNA. Double-stranded RNA was identified by reaction with antisera specific for double-stranded RNA, capacity to protect primary rabbit kidney cells against virus infection, and relative ribonuclease resistance. The presence of such double-stranded RNA in virus preparations provides an explanation for how inactivated crude suspensions of single-stranded RNA virus virions may induce interferon in the absence of detectable viral replication. Serologically active double-stranded RNA was also detected in normal chick embryo cell nucleic acid extracts. This differed greatly from double-stranded viral RNA, however, since the serologic activity was more sensitive to destruction by ribonuclease than the viral dsRNA and it did not stimulate resistance to virus infection in primary rabbit kidney cells. The authors are indebted to W. P. M. Fisher, Marilyn Johnston, Mary-Ellen Davies, and Helen Perry for excellent technical assistance.