TOPOLOGY OF BOVINE ROTAVIRUS (RF STRAIN) VP6 EPITOPES BY REAL-TIME BIOSPECIFIC INTERACTION ANALYSIS

An automated biosensor system designed for measuring molecular interac tions in real-time (BIAcore) was used to characterize monoclonal antib odies (Mabs) raised against the inner capsid protein (VP6) of the bovi ne rotavirus (RF strain). Six Mabs, all reactive in Western blot and i n indirect immunofluorescence assays, were mapped, using purified reco mbinant VP6. These Mabs were delineated into several groups of antibod ies. Interactions of selected monoclonal antibodies with purified vira l particles were studied by the BIAcore methodology. We showed that so me Mabs did not react with single-shelled particles. Conversely, sever al Mabs reacted with single-shelled particles and one antibody reacted with both single-shelled and double-shelled particles. The latter Mab seemed to interact with VP6 through the holes of the outer capsid and its interaction with the double-shelled particles induced a significa nt decapsidation. These results allowed a better characterization of t he epitopes of VP6. The localization of the epitopes in the viral part icle is discussed in comparison with a pepscan study that determined t he reactivity of Mabs with nested heptapeptides derived from the whole VP6 molecule. (C) 1994 Academic Press, Inc.