Purification method for cell-cultured influenza virus H5N1

Objective To reduce the residual proteins and DNA of host cells in the preparation of H5N1 influenza A virus. Methods Core 700 was firstly used to remove residual host cell proteins, and then Capto Q was used to remove host cell DNA. Several batches of H5N1 influenza A virus cultured in Madin-Darby canine kidney (MDCK) cells were purified using this method. The efficiency of purification was evaluated using many methods including quantitative real-time PCR, hemagglutination (HA) test and single radial immunodiffusion assay. Moreover, Benzonase nuclease was used for comparison. Results Without the use of Benzonase nuclease, the overall removal rates of host cell DNA and residual proteins were 99.62% and 98.1%, and the HA antigen recovery rate was 66.96%. Conclusions This study established a purification strategy with good effect for cell-based influenza vaccines. It can efficiently remove host cell DNA and proteins and achieve a high HA recovery rate. The purification result is no worse than that of adding Benzonase nuclease, suggesting the potential of its application in actual vaccine production. Key words: Influenza virus; MDCK cells; Host cell protein; Host cell DNA; Purification