Expression and Characterization of Avian Reovirus SigmaC-MBP Fusion Proteins as ELISA Antigens

Research Poster
Linda Michel
Research Scientist
Daral Jackwood
Food Animal Health Research Program

Avian reoviruses (ARV) belong to the Orthoreovirus genus in the family Reoviridae. They are widespread in chickens and turkeys and have been linked to several diseases in poultry; most notably tenosynovitis in chickens. ARV strains form at least six distinct genotype clusters. The ARV protein primarily responsible for this diversity is SigmaC, which induces the formation of neutralizing antibodies that protect chickens from disease. The presence of these antibodies can be detected with commercial ELISA kits. Increasing antigenic diversity of the virus, however, may decrease the effectiveness of this assay for detection of ARV antibodies. To circumvent this problem, we used a platform expression system to produce the SigmaC protein fused to a maltose binding protein (MBP) tag to facilitate purification. ARV strains were isolated from infected broilers and the SigmaC gene was sequenced. Genes from different genotypes were cloned into an MBP fusion plasmid transfer vector and then transfected into the genome of baculovirus under the control of the polyhedron promotor. SigmaC-MBP expressed from baculovirus cultures was purified over amylose resin and used to coat ELISA plates. An ELISA was performed using serum from chickens infected with ARV from different genotypes. The results indicate the different SigmaC-MBP antigens reacted stronger to homologous ARV antibodies.