Free and Cell Associated Pertussis Toxin Antigen Quantification to Determine Bordetella Pertussis Appropriate Harvesting Time by ELISA Method

Duration of whole cell pertussis (WCP) fermenter culture affects the quality and quantity of the Bordetella pertussis PTX production which directly influence in pertussis vaccine potency, and in this way, has a significant consequence on vaccine immunogenicity. The aim of this research was to quantify the cell associated and free pertussis toxin antigen by ELISA method to determine the optimal and appropriate harvesting time for WCP vaccine production. The PTX antigen levels were measured in three series of fermenter (350 L) batches (A, B and C) of WCP vaccine strain 509, cultivated in culture media B2 in optical densities of 0.1, 0.8, 1.1, 1.2, 1.3. Each sample was quantitatively evaluated in three modes of sediment, supernatant and suspension of WCP vaccine compared to standard pertussis toxin by ELISA and analyzed using Excel software. According to the analysis of the results which was interpreted based on maximum amount of the PTX antigen anchor to Bordetella pertussis, optimal duration of the fermenter (350 L) culture of WCP strain 509, was determined for 38 to 42 hours at optical density of 1.2. Due to the disadvantages of turbidity method and the advantages of PTX antigen measurement by ELISA method (quantitative, qualitative and repeatability), this approach promises a reliable method in order to effective control of parameters and procedures in production process, in process quality control (IPQC) and consistency approach of WCP vaccine production.