Isolation and Purification of a Polymeric Form of the Glycoprotein of Rabies Virus

Abstract

Of the 3 major proteins associated with the rabies virus membrane, only the glycoprotein was located on the external surface of the virus membrane. Glycoprotein prepared by treatment of rabies virus with Triton X-100 and purified by isoelectric focusing was homogeneuos with respect to size and isoelectric point. This material, which is free of phospholipids, is able to protect in vaccination experiments [in mice] against a lethal challenge infection with rabies virus. The apparent MW of this component isolated under non-denaturing conditions is approximately 400,000. The same material analyzed by SDS polyacrylamide gel electrophoresis (PAGE) consisted soley of polypeptide chains of the G protein (MW 80,000). A minor glycoprotein (gp 50), detected by PAGE of the Triton X-100 released material, appeared to be a breakdown product of the G-protein. Therefore the detergent released material represents homopolymers of the G-protein. Whether the antigenic determinants reside on the monomeric subuint or are a property of the polymeric form of the G-protein is disucssed.