An unconventional enzyme-immunoassay for the evaluation of antigenic potency of bacterial extracts

Background. The evaluation of the antigen concentration of bacterial vaccines is crucial both on raw materials and in final products, such as drugs. Bacterial lysates are used in humans to improve the immune response during upper respiratory tract infections. Methods. An enzyme immunoassay, which employs a single specific antiserum and suboptimal concentration of antigen coated to plastic wells, was developed to evaluate the concentration of antigens in Branhamella catarrhalis lysates. Results. Sensitivity was good with detection of only a few nanograms of antigen, and better than that of the rocket electrophoresis used as the reference method. The assay was highly reproducible both in intra-day and between-day experiments. For this reason, it is suitable for use both in routine quality control and during the research and development of new antigenic products. Conclusions. The control of the production process of infectious agent-derived antigens in the pharmacological industry could be significantly improved using this low-cost, easily automated assay.