Attachment of the gammaherpesvirus bovine herpesvirus 4 is mediated by the interaction of gp8 glycoprotein with heparinlike moieties on the cell surface

Abstract

Cell surface heparan sulfate serves as the initial receptor for several alphaherpesviruses and at least one betaherpesvirus. This study shows that during the process of adsorption of the gammaherpesvirus bovine herpesvirus 4 (BHV-4), the viral glycoprotein gp8 interacts with heparinlike moieties of cell surface. This conclusion is based on the following findings. (i) Soluble heparin was capable of blocking BHV-4 infection of Georgia bovine kidney cells by inhibition of viral attachment. (ii) Nevertheless, after virus adsorption to Georgia bovine kidney cells, heparin was partially capable of removing adsorbed virus. (iii) Enzymatic digestion of cell surface heparan sulfate but not of chondroitin sulfates A, B, and C reduced the binding of the virus to the cells, and rendered the cells partially resistant to infection. (iv) Radiolabeled purified BHV-4 bound to wild-type Chinese hamster ovary cells, whereas binding of the virus to mutant Chinese hamster ovary cell lines that where deficient in either all glycosaminoglycans or only heparan sulfate was significantly impaired. (v) Using heparin-affinity chromatography, gp8 glycoprotein was shown to bind specifically to immobilized heparin and to elute in the presence of soluble heparin. These data together showed that the gammaherpesvirus BHV-4, like alphaherpesviruses and one betaherpesvirus, adsorbs to cells by binding to cell surface heparin-like moieties. Therefore, this study extends the group of herpesviruses interacting with heparinlike moieties at the cell surface to a member of the gammaherpesvirinae subfamily.