title: Physicochemical and immunochemical assays for monitoring consistent production of tetanus toxoid.
abstract: The detoxification of tetanus toxin by formaldehyde is a crucial step in the production of tetanus toxoid. The inactivation results in chemically modified proteins and it determines largely the ultimate efficacy and safety of the vaccine. Currently, the quality of tetanus toxoid lots is evaluated in potency and safety tests performed in animals. As a possible alternative, this article describes a panel of in vitro methods, which provides detailed information about the quality of tetanus toxoid. Ten experimental lots of tetanus toxoid were prepared using increasing concentrations of formaldehyde and glycine to obtain tetanus toxoids having differences in antigenicity, immunogenicity, residual toxicity and protein structure. The structural properties of each individual toxoid were determined using immunochemical and physicochemical methods, including biosensor analysis, ELISA, circular dichroism, TNBS assay, differential scanning calorimetry, fluorescence and SDS-PAGE. The quality of a tetanus toxoid lot can be assessed by these set of analytical techniques. Based on antigenicity, immunogenicity and residual toxicity data, criteria are formulated that tetanus toxoids lot have to meet in order to have a high quality. The in vitro methods are a valuable selection of techniques for monitoring consistency of production of tetanus toxoid, especially for the detoxification process of tetanus toxin.
authors.affiliation: Institute for Translational Vaccinology, P.O. Box 450, 3720 AL Bilthoven, The Netherlands. bernard.metz@rivm.nl
authors.forename: Bernard
authors.initials: B
authors.lastname: Metz
authors.forename: Wichard
authors.initials: W
authors.lastname: Tilstra
authors.forename: Robert
authors.initials: R
authors.lastname: van der Put
authors.forename: Nanda
authors.initials: N
authors.lastname: Spruit
authors.forename: Jan
authors.initials: J
authors.lastname: van den Ijssel
authors.forename: Jolanda
authors.initials: J
authors.lastname: Robert
authors.forename: Coenraad
authors.initials: C
authors.lastname: Hendriksen
authors.forename: Gideon
authors.initials: G
authors.lastname: Kersten
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods; D005260:Female; D005557:Formaldehyde / Q000737:chemistry*; D011786:Quality Control; D013744:Tetanus Toxin / Q000737:chemistry* / Q000494:pharmacology*; D013745:Tetanus Toxoid / Q000009:adverse effects / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D013744:Tetanus Toxin; D013745:Tetanus Toxoid; D005557:Formaldehyde
keywords: Immunochemical techniques; Physicochemical techniques; Potency; Structural characterization; Tetanus toxoid; Vaccine; formaldehyde