Tangential Flow Filtration for the Recovery of Acellular Pertussis Vaccine Components

Membrane-based TFF technology can ease scale-up and provide a higher recovery percentage compared to conventional purification methods.
Oct 01, 2009


The commercial preparation of acellular pertussis vaccine depends on the effective recovery and purification of the antigens pertussis toxin (PT), filamentous haemaglutinin (FHA), and pertactin (PRN) from Bordetella pertussis fermentation. This study describes the recovery of the antigens using an open channel 0.45-μm tangential flow filtration module with optimization of the process parameters of transmembrane pressure, cross flow, and flux. Under the optimized conditions, greater than 98% recovery of FHA and PT was obtained.

Pertussis or whooping cough is an acute infectious disease of the respiratory tract caused primarily by Bordetella pertussis and less commonly by Bordetella parapertussis.1 Pertussis still continues to cause significant morbidity and mortality globally. "Per" meaning intensive and "tussis" cough: describes the clinical manifestation of the disease characterized by coughing and minor systemic complaints predominant in children.2 B. pertussis is a nonmotile gram-negative coccobaccilli less than 1 μm in width and length. Diptheria toxoid and tetanus toxoid combined with whole-cell pertussis (DTP vaccine) has long been in use for childhood immunization programs. Whole-cell DTP vaccines are associated with local adverse reactions like erythrema, swelling, fever, and mild systemic events, e.g., convulsions and hypotonic hyporesponsive events.3 The reactogenecity of the whole cell pertussis vaccine has evoked public controversy in several countries and prompted the development of the acellular pertussis vaccine, which has a lower rate of adverse events and is effective in preventing pertussis.

Pathogensis of pertussis is a complex process and not completely understood. It includes pertussis toxin, filamentous hemagglutinin, pertactin, tracheal colonization factor (TCF), serum bactericidal resistance factor (BrkA), tracheal cytotoxin (TCT), adenyl cyclase toxin-hemolysin (ACT), lipoplooligosaccharide (LOS), heat labile toxin (HLT), and fimbriae 2 and 3 (Fims 2 & 3).4 Acellular pertussis vaccines contain inactivated pertussis toxin (PT), 105 kD, and may contain one or more of the bacterial components: filamentous hemagglutinin (FHA), 220 kD, a 69 kD outer membrane protein pertactin (PRN), and Fims 2 & 3.

To keep the disease under control large amounts of PT, FHA, and PRN must be prepared for mass immunization. The first step toward purification is the clarification of the fermentation broth for the recovery and further downstream processing of the antigens. The traditional method available is centrifugation. The scale-up of the process using centrifugation may lead to lower recovery of the antigens and a huge capital investment with low scalability. Therefore, an efficient bioseparation technique that can be easily scaled up with lesser capital investment is necessary. Membrane-based technology for biopharmaceuticals has been widely suggested and used.5,6 Tangential flow filtration (TFF) technology using an open channel, steam-sterilizable device allows microorganisms to be washed and concentrated in an efficient, rapid manner by using a closed recirculating filtration system, where both the concentrated cell mass and the filtrate can be collected under aseptic conditions. The factors that must be considered for successful scale-up of TFF technology are purity, yield, and reproducibility, for which the process parameters of the TFF must be optimized accurately. This article describes the optimization of the TFF process for high recovery of the acellular pertussis vaccine antigenic components: PT and FHA.

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