title: Transferability study of CHO cell clustering assays for monitoring of pertussis toxin activity in acellular pertussis vaccines.
abstract: Current regulations for acellular pertussis (aP) vaccines require that they are tested for the presence of residual or reversion-derived pertussis toxin (PTx) activity using the mouse histamine sensitisation test (HIST). Although a CHO cell clustering assay can be used by manufacturers to verify if sufficient inactivation of the substance has occurred in-process, this assay cannot be used at present for the final product due to the presence of aluminium adjuvants which interfere with mammalian cell cultures. Recently, 2 modified CHO cell clustering assays which accommodate for the adjuvant effects have been proposed as alternatives to the HIST. These modified assays eliminate the adjuvant-induced cytotoxicity either through dilution of the vaccine (called the Direct Method) or by introducing a porous barrier between the adjuvant and the cells (the Indirect Method). Transferability and suitability of these methods for testing of products present on the European market were investigated during a collaborative study organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM). Thirteen laboratories participated in this study which included 4 aP-containing vaccines spiked by addition of PTx. This study also assessed the transferability of a standardised CHO cell clustering assay protocol for use with non-adjuvanted PTx preparations. Results showed that the majority of laboratories were able to detect the PTx spike in all 4 vaccines at concentrations of 4 IU/mL or lower using the Indirect Method. This sensitivity is in the range of the theoretical sensitivity of the HIST. The Direct Method however did not show the expected results and would need additional development work.
authors: Health Canada, Biologics and Genetic Therapies Directorate, Centre for Biologics Evaluation, 100 Eglantine Dr., Ottawa, K1A 0K9, Canada.
authors: R
authors: R
authors: Isbrucker
authors: European Directorate for the Quality of Medicines & HealthCare (EDQM), Department of Biological Standardisation, OMCL Network & HealthCare (DBO), Council of Europe, Strasbourg, France.
authors: A
authors: A
authors: Daas
authors: Center for Biologics, Evaluation, and Research, US Food and Drug Administration, 10903 New Hampshire Avenue, MD 20993, Silver Spring, USA.
authors: L
authors: L
authors: Wagner
authors: European Directorate for the Quality of Medicines & HealthCare (EDQM), Department of Biological Standardisation, OMCL Network & HealthCare (DBO), Council of Europe, Strasbourg, France, angele.costanzo@edqm.eu.
authors: A
authors: A
authors: Costanzo
mesh_terms: D000818:Animals; D016466:CHO Cells; D002626:Chemistry, Pharmaceutical / Q000379:methods / Q000592:standards*; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D051379:Mice; D037342:Pertussis Toxin / Q000302:isolation & purification* / Q000592:standards* / Q000627:therapeutic use; D010567:Pertussis Vaccine / Q000592:standards* / Q000627:therapeutic use; D022282:Vaccines, Acellular / Q000592:standards* / Q000627:therapeutic use
chemical_list: D010567:Pertussis Vaccine; D022282:Vaccines, Acellular; D037342:Pertussis Toxin
keywords: 3Rs; Biological Reference Preparation; Biological Standardisation Programme; CHO cell clustering assay; Pertussis toxin; acellular pertussis vaccine; alternative assay; biological standardisation; collaborative study; mouse histamine sensitisation test