Comparison of the binding characteristics to BHK-21 cells of viruses representing the two Theiler's virus neurovirulence groups.

The binding characteristics of the highly virulent GDVII and less virulent BeAn strains of Theiler's murine encephalomyelitis viruses (TMEV) to whole BHK-21 cells were determined using a direct viral binding assay. The overall rates of association and dissociation of BeAn and GDVII viruses were similar. Using a saturation binding assay intended for multivalent ligands, such as picornaviruses, the number of binding sites per cell was calculated as 1.6 x 10(5). Competitive binding assays with both viruses showed one-way blocking. In addition, treatment of cell monolayers with neuraminidase reduced binding of BeAn virus by 90% but did not affect GDVII binding. Wheat germ agglutinin, a lectin which blocks binding to sialic acid and N-acetylglucosamine residues, substantially reduced binding of radiolabeled GDVII and BeAn viruses. Treatment of asialylated cells with O-glycanase further reduced the binding of BeAn virus, suggesting that O-linked oligosaccharides are involved in viral binding. These results suggest members of the two TMEV virulence groups share a common receptor but bind it differently.