Preparation and properties of an inhibitory extract from frog virus 3 particles

The structural constituents of the frog virus 3 particle were solubilized by treatment with a nonionic detergent followed by the addition of a high salt concentration. This soluble viral extract (SVE) inhibits host nucleic acid synthesis. Its activity on RNA synthesis was studied in KB cells and found to be dependent on the presence of DEAE dextran. Inactivation of the inhibitory properties of SVE were obtained by trypsin digestion, treatment with urea, or heat denaturation. Neutralization of the activity of SVE was obtained by anti-frog virus 3 serum but not by anti-BHK serum. In vitro a complex may be formed between polynucleotides and the inhibitor indicating a possible mechanism for vivo inhibition.