Use of protamine sulphate for elimination of substrate DNA in poliovaccines produced on continuous cell lines.

Cell substrate DNA was shown to be an abundant contaminant in the clarified preparations of the Sabin type 1, 2 and 3 poliovaccines produced on a continuous cell line (4647). The size of the DNA, as evaluated for the Sabin type 1 poliovaccine, was highly heterogeneous, ranging from 100 to 20,000 base pairs. In view of potential oncogenicity of this DNA a simple and efficient procedure for its elimination is proposed. The method is based on use of protamine sulphate which at the concentration of 2.0 mg ml-1 precipitated cell DNA almost completely without affecting the virus titres.