Studies on a detection method of residual host cell DNA in Sabin strain inactivated poliovirus vaccine

Objective To establish a method of detecting residual Vero cell DNA in Sabin strain inactivated poliovirus vaccines. Methods The genomic DNA of Vero cell was extracted. Digoxigenin labeled probe was prepared. The detection results of samples treated with two different methods were compared. The specificity, sensitivity and stability of the established method were verified. Results The concentration of Vero cell DNA was 295 μg/ml, and the ratio of absorbance at 260 nm and 280 nm was 1.88. Probe sensitivity was 0.01 pg/μl. The sensitivity of the method was 1 ng when DNA reference was treated with phenol, and reached 10 pg when the reference was treated with sodium iodide. No hybridization between the probe and non-homologous DNAs was observed. The sensitivity remained 10 pg 9 months after the probe was conserved at -70 ℃. Conclusions The detection method of residual Vero cell DNA in Sabin strain inactivated poliovirus vaccines is developed. Sodium iodide has advantages of both high recovery and easy operation for DNA extraction. It is suitable for residual Vero cell DNA detection. Key words: Poliovirus vaccine, inactivated; DNA contamination; Vero cells; Methods