Host-dependent variation of Bluetongue virus neutralization

Abstract

To determine if neutralizing epitopes of Bluetongue virus (BTV) 17 are host dependent, e.g., that monoclonal antibodies (mAb) to Bluetongue virus 17 (BTV 17) differ in their ability to neutralize BTV infectivity in insect versus mammalian cells, a panel of neutralizing mAb was developed. The relative neutralizing titer of eight mAb for BTV 17 infectivity in mammalian versus insect target cells was determined. Four mAb differed in their relative neutralization titer when assayed on mammalian target cells as compared to insect target cells. These findings suggest that different epitopes involved in neutralization might be important in virus infectivity and neutralization in mammalian versus insect target cells. To determine which viral protein(s) these mAb bind, the specificity of the mAb was determined by radioimmunoprecipitations. Five BTV 17 neutralizing mAb bound to the major outer coat protein P2, a 98-kDa protein, whereas the BTV protein(s) bound by the other three neutralizing mAb could not be determined. The potential role of the two BTV outer coat proteins in infection of mammalian and insect host cells is discussed.