title: Modified binding assay for improved sensitivity and specificity in the detection of residual pertussis toxin in vaccine preparations.
abstract: A binding assay was recently published that differentiates between pertussis toxin (PTx) and the pertussis toxoid (PTd) used in acellular pertussis vaccines based on the selective binding of PTx to fetuin and detection with a polyclonal antibody. We found that the assay specificity for PTx was affected by both pH and salt. A monoclonal antibody (mAb) was identified that eliminated specificity problems and improved the sensitivity to 0.4 ngPTx/ml. This mAb was previously shown to neutralize PTx toxicity in vivo, thereby supporting the assay's potential biological relevance as an alternative to the mouse histamine sensitivity test for the safety of pertussis vaccines.
authors.affiliation: Health Canada, Biologics and Genetic Therapeutics Directorate, Center for Biologics Research, 251 Sir Frederick Banting Dr., A/L 2201E, Ottawa, Ontario K1A 0K9, Canada. Richard.Isbrucker@hc-sc.gc.ca
authors.forename: Richard A
authors.initials: RA
authors.lastname: Isbrucker
authors.forename: Alex
authors.initials: A
authors.lastname: Bliu
authors.forename: Fiona
authors.initials: F
authors.lastname: Prior
mesh_terms: D000911:Antibodies, Monoclonal / Q000378:metabolism; D000992:Antitoxins / Q000378:metabolism; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay / Q000379:methods; D009994:Osmolar Concentration; D037342:Pertussis Toxin / Q000032:analysis*; D011485:Protein Binding; D012680:Sensitivity and Specificity; D014612:Vaccines / Q000737:chemistry*; D000509:alpha-Fetoproteins / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000992:Antitoxins; D014612:Vaccines; D000509:alpha-Fetoproteins; D037342:Pertussis Toxin