Effect of Solution Environment on the Purification of Pertussis Toxin

The low recovery of pertussis toxin (PT) and the low resolving efficiency of chromatography, due to the instability of PT in low salt condition, are the main challenges for its purification. We applied 2 M urea to prevent the aggregation and disassociation of PT during the purification by ionexchange chromatography (IEC) and gel filtration chromatography (GFC). The effect of urea on the purification of PT was investigated by ELISA assay and non-reduced SDS-PAGE. The activity recoveries of PT and filamentous hemagglutinin (FHA) in IEC and GFC, the resolution efficiency in GFC, and the purities of PT and FHA were improved obviously by adding 2 M urea in the mobile phase. The results highlight the potential application of urea in the acellular pertussis vaccine (APV) manufacture procedure.