Detection of cellular receptors specific for the hepatitis B virus preS surface protein on cell lines of extrahepatic origin

Hepatitis B virus infection is primarily mediated by the interaction of the preS region of the viral envelope protein with its still unknown cellular receptor. Using recombinantly expressed preS proteins, the distribution of preS-binding receptors on cell lines from extrahepatic origins was determin ed by immunofluorescence and flow cytometry. In contrast to human liver cel l lines, most cell lines from extrahepatic origins did not bind preS protei ns. Nevertheless, exceptions were found in the bone marrow-derived cell lin e, KG-1, and the osteogenic sarcoma cell line SaOS-2, as well as in the pre viously reported EBV-transformed B-cell line, Wa. To determine the biochemi cal nature of these receptors, Wa-cells were cell surface biotinylated and the preS-binding receptors were isolated by immunoprecipitation. A specific band with a molecular weight of similar to 30 kDa was identified in a SDS- polyacrylamide gel, which further characterization is expected to provide c lues regarding the infection mechanism of HBV in hepatic- and extra-hepatic cells. (C) 2000 Academic Press.