Determination of foetal calf serum in vaccine preparations by immunoradiometric assay and enzyme-linked immunosorbent assay.
A simple and sensitive immunoradiometric assay (IRMA) for detection of foetal calf serum proteins in vaccine preparations has been developed. In this two-site sandwich assay the same preparation of polyclonal anti-FCS immunoglobulin (IgG) was used for coating the solid phase (as a capture antibody) and in a labelled form (I-125 labelled) for detection. The developed assay allows precise and accurate quantification of FCS proteins (down to 10 ng/ml) in vaccine preparations and has been used for screening of FCS residues (a) during production of measles vaccine, and (b) in various different commercial vaccine preparations. An enzyme-linked immunosorbent assay (ELISA) was also developed based on the same assay two-site sandwich principle, where anti-FCS was directly labelled with horse-radish peroxidase. ELISA was comparable in sensitivity and accuracy with IRMA.