Monoclonal Antibodies to Bluetongue Virus Define Two Neutralizing Epitopes and a Hemagglutinating Epitope

Monoclonal antibodies were used to characterize neutralizing epitopes on VP2 of bluetongue virus serotype 10 (BTV-10). Six neutralizing monoclonal antibodies that immune precipitated VP2 demonstrated two distinct patterns of reactivity in the competitive enzyme-linked immune absorbent assay (ELISA). These results suggest that there are at least two distinct domains of neutralization on VP2 of BTV. Monoclonal antibodies defining the two domains were serotype-restricted in plaque neutralization, immune precipitation or ELISA. One of the two neutralizing domains also demonstrated significant hemagglutinating activity. Both cattle and sheep infected with BTV-10 produce antibodies to the two neutralizing epitopes.