Evaluation of Pertussis Toxin Expression in B۲ and THIJS Media

Whole-cell pertussis vaccine (wP) has been imperative and highly effective in preventing childhood deaths due to pertussis. Pertussis toxin is one of the virulence factors of Bordetella pertussis in all available pertussis vaccines. wP production in Razi Vaccine and Serum Research Institute is according to bioreactor culture of B. pertussis strains in B۲ medium. The aim of this study was to evaluate B. pertussis strain ۵۰۹ PT production in B۲ and Thalen-IJssel (THIJS) media by Chinese Hamster Ovary (CHO) cell and enzyme-linked immunosorbent assay methods (ELISA). In the current study, B. pertussis strain ۵۰۹ was cultured in B۲ and THIJS media. Six samples were taken during the log growth phase within ۲-۳ h intervals (triplicate). The growth rate was calculated using opacity and the quantification of cell-associated and released PT measured by ELISA and CHO cell assays. THIJS medium was significantly showed an increase in the bacterial growth rate. During the first ۲۹ h, bacterial concentrations in B۲ and THIJS culture medium were ۱۹ and ۲۹ IOU, respectively. In THIJS medium, greater amount of pertussistoxin production was cell-associated. In B۲ medium, maximum cell-associated toxin by ELISA and CHO cell assays were in the ODs of ۱.۱ and ۰.۹ and for THIJS medium in the ODs of ۱.۶ and ۱.۱, respectively. B. pertussis strain ۵۰۹ in THIJS medium produced higher cell mass and cell-associated pertussis toxin than that of B۲. It can be used for the production of whole-cell vaccine with higher pertussis toxin and accordingly using lower biomass per dose leading to the reduction of vaccine toxicity.