Improved Efficiency of Bluetongue Viral Antigen Isolation for Successful Immunization

Abstract

Bluetongue (BT) is a viral disease transmitted by Culicoides spp. The clinical presentation of BT varies widely among susceptible sheep, and in most cases results in severe illness and death in the infected animals. The mortality among susceptible sheep ranges from 2-30% but can occasionally be as high as 70%. Therefore, we investigated a new method to increase the purified BTV-antigen. BTV viral suspensions were purified using Freon-113 and ultracentrifugation through 40% sucrose. We obtained 94.5-95.8% purification of the BT-16 viral antigen. Sheep and cows were immunized with the isolated BTV antigen obtained from this method to confirm antibody specificity to BTV. The antibody activity measured by enzyme-linked immunosorbent assay (ELISA) from goat serum was 7.0log2 to 13.0log2 (on average 10.8±2.28log2) relative to that of sheep (P<0.05 to P<0.0001). We show here that this method can successfully purify BTV-16 antigen and could be used for large-scale production and other BTV serotypes.