An in vitro approach in quality control of toroid vaccines

For routine immunogenicity testing of traditionally produced vaccines, anim al tests are required by regulatory authorities, with potency estimated in International Units. A new concept focuses on assuring immunogenicity by mo nitoring batch-to-batch consistency in production. This concept is used for well-defined biologicals such as hormones. Through the use of immunochemic al and bio- and physiocochemical techniques the traditional products can be characterised as completely as possible. Developments in in vitro methodol ogies offer opportunities for immunogenicity testing in vitro. This study d escribes the possibilities for applying the consistency concept to the trad itional products, tetanus and diphtheria toxoids. The sources of variation in these products were studied by flocculation time, SDS-PAGE, biosensor an alysis, gelpermeation chromatography and in vitro cytokine production studi es. Batch-to-batch variation was shown using these in vitro techniques. Res ults indicate that it is possible to apply the consistency concept in the q uality control of traditional vaccines like tetanus and diphtheria toxoids. (C) 2001 Elsevier Science Ltd. All rights reserved.