Assay of Defective-interfering Semliki Forest Virus by the Inhibition of Synthesis of Virus-specified RNAs

Abstract
A simple, rapid and reproducible assay for defective-interfering Semliki Forest virus (DI SFV), which is based on the inhibition of synthesis of virus-specified RNA in SFV-infected cells, is described. Using the assay, it was shown that DI virus is generated by a single passage in baby hamster kidney (BHK) cells in an inoculum which contained no detectable DI virus. The UV target size of the interfering activity was calculated.