Recombinant Bordetella pertussis pertactin (P69) from the yeast Pichia pastoris: high-level production and immunological properties.

Acellular whooping cough vaccines are based on pertussis toxoid but their effectiveness may be increased by the addition of other Bordetella pertussis antigens. We expressed the immunogenic outer membrane protein pertactin (P69) from B. pertussis to high levels in multi-copy transformants of the industrial yeast Pichia pastoris. In high-density fermentations, engineered P. pastoris yielded greater than 3 g of the protein per litre of culture. Purified recombinant pertactin was able to stimulate the incomplete protection afforded by toxoid to the level of the whole-cell vaccine, as shown by the Kendrick test, supporting its inclusion in future acellular vaccines.