Assays for Determining Pertussis Toxin Activity in Acellular Pertussis Vaccines

Abstract

Whooping cough is caused by the bacterium Bordetella pertussis. There are currently two types of vaccines that can prevent the disease; whole cell vaccines (WCV) and acellular vaccines (ACV). The main virulence factor produced by the organism is pertussis toxin (PTx). This toxin is responsible for many physiological effects on the host, but it is also immunogenic and in its detoxified form is the main component of all ACVs. In producing toxoid for vaccines, it is vital to achieve a balance between sufficiently detoxifying PTx to render it safe while maintaining enough molecular structure that it retains its protective immunogenicity. To ensure that the first part of this balancing act has been successfully achieved, assays are required to accurately measure residual PTx activity in ACV products accurately. Quality control assays are also required to ensure that the detoxification procedures are robust and stable. This manuscript reviews the methods that have been used to achieve this aim, or may have the potential to replace them, and highlights their continuing requirement as vaccines that induce a longer lasting immunity are developed to prevent the re-occurrence of outbreaks that have been observed recently.

Pharmacological targeting of host chaperones protects from pertussis toxin in vitro and in vivo

“…We have shown other membrane 34 . This phenomenon is the basis of routine assays to determine monoclonal antibody function and to measure antitoxin responses 51,52 . Here, we utilized this CHO-K1 assay and pharmacological inhibitors of heat shock proteins, Cyps and FKBPs to show PT interactions with Hsp90, Hsp70, FKBP and Cyps are required for PT-intoxication of CHO-K1 cells.…”

iGIST - a kinetic bioassay for pertussis toxin based on its effect on inhibitory GPCR signaling

“…Thus, tests for residual PTX activity are instrumental for ACV development and manufacturing. Mouse histamine sensitization test (HIST) is a benchmark PTX assay in the vaccine industry capable of detecting PTX at ng/ml levels 17 . HIST is based on the early observation of PTX-treated mice becoming sensitive to histamine 18 .…”

“…HIST is based on the early observation of PTX-treated mice becoming sensitive to histamine 18 . Mice are exposed to PTX-containing preparations, challenged with histamine and monitored for death 17 .…”

“…Though it has a long record in the industry, HIST is a terminal assay causing profound stress for the animals. Besides, HIST requires large amounts of animals, with a recent global annual estimate of 65.000 mice 17 . preprint (which was not certified by peer review) is the author/funder.…”

A Review on Bacterial Respiratory Infections and Optimization of Their Identification

“…At present, two types of vaccines exist to prevent the disease. These bacteria attach and proliferate extracellularly in the airways and secrete several toxins with a variety of local and systemic effects on the host cells (38)(39)(40)(41) .…”