FORMATION OF NATIVE HEPATITIS-C VIRUS GLYCOPROTEIN COMPLEXES

The hepatitis C virus (HCV) glycoproteins (E1 and E2) interact to form a heterodimeric complex, which has been proposed as a functional subu nit of the HCV virion envelope. As examined in cell culture transient- expression assays, the formation of properly folded, noncovalently ass ociated E1E2 complexes is a slow and inefficient process. Due to lack of appropriate immunological reagents, it has been difficult to distin guish between glycoprotein molecules that undergo productive folding a nd assembly from those which follow a nonproductive pathway leading to misfolding and aggregation. Here we report the isolation and characte rization of a conformation-sensitive E2-reactive monoclonal antibody ( H2). The H2 monoclonal antibody selectively recognizes slowly maturing E1E2 heterodimers which are noncovalently linked, protease resistant, and no longer associated with the endoplasmic reticulum chaperone cal nexin. This complex probably represents the native prebudding form of the HCV glycoprotein heterodimer. Besides providing a novel reagent fo r basic studies on HCV virion assembly and entry, this monoclonal anti body should be useful for optimizing production and isolation of nativ e HCV glycoprotein complexes for serodiagnostic and vaccine applicatio ns.