QUANTIFICATION OF WHOLE VIRUS-PARTICLES (146S) OF FOOT-AND-MOUTH-DISEASE VIRUS IN THE PRESENCE OF VIRUS SUBUNITS (12S), USING MONOCLONAL-ANTIBODIES IN A SANDWICH ELISA

This paper describes a method for the specific quantification of whole virions Of foot-and-mouth disease (146S) in the presence of virus sub units (12S). The method involves the use of virus neutralising monoclo nal antibodies directed against a linear epitope of the VP1 loop regio n of a type O virus The monoclonal antibodies were used as both captur e and detecting reagents (labelled with horse radish peroxidase) in a sandwich ELISA. Such monoclonal antibodies also have the advantage tha t they do not detect viruses containing proteolytically cleaved VP1, t hus the assay system is ideal for estimation of whole particles in vac cine manufacture where the immunogenicity of the vaccine depends on vi rus integrity (whole virions being present) and uncleaved capsid prote in VP1. Other combinations of different anti-type O FMD virus monoclon al antibodies used as capture and detecting reagents were also examine d. The system could be adapted to on-line continuous testing of virus being produced during a manufacturing run allowing maximisation of vir us yield and quality control.