A CELL-SURFACE PROTEIN THAT BINDS AVIAN HEPATITIS-B VIRUS-PARTICLES

We have identified a 180-kDa cellular glycoprotein (gp180) that binds with high affinity to duck hepatitis B virus (DHBV) particles. The pro tein was detected by coprecipitating labeled duck hepatocyte proteins with virions or recombinant DHBV envelope proteins, using nonneutraliz ing monoclonal antibodies to the virion envelope. Binding of gp180 req uires only the pre-S region of the viral large envelope protein, since recombinant fusion proteins bearing only this region efficiently copr ecipitate gp180. The DHBV-gp180 interaction is blocked by two independ ent neutralizing monoclonal antibodies. The protein is found on both i nternal and surface membranes of the cell, and the species distributio n of gp180 binding activity mirrors the known host range of DHBV infec tion. Functional gp180 is expressed in a wide variety of tissues in su sceptible ducks.