Identification of human hepatocyte protein(s), which binds specifically to the recombinant envelope-2/non-structural-1 protein of hepatitis C virus

Hepatitis C virus (HCV), which is the major pathogen responsible for human chronic liver disease, has special tropism for hepatocytes. Although, low-density lipoprotein receptor, CD81 and negatively charged glycosaminoglycans have been proposed as candidate receptors for HCV, no confirmed receptor(s) on the hepatocytes have been identified to date. It is also suggested that additional, yet unidentified, cellular proteins may be involved in the host-viral interaction. Therefore, this study was conducted with the main aim to identify hepatocyte protein(s) that may have affinity for the HCV structural protein, envelope-2/non-structural-1 (E2/NS1) protein. For the binding studies, hepatocytes were isolated from fresh normal human liver tissues. The hepatocyte proteins on the nitrocellulose paper were reacted with recombinant E2/NS1 protein and anti-E2 (rabbit). In another approach, to rule out the possibility of binding of rec-E2/NS1 with the hepatocyte cytoplasmic proteins, hepatocyte plasma membrane proteins were passed through CNBr-activated and recombinant E2/NS1 bound sepharose-4B column. The recombinant E2/NS1 binding hepatocyte plasma membrane protein(s) were eluted and were then analyzed. Altogether, our data suggest that E2/NS1 protein of HCV binds to two hepatocyte proteins of molecular weights 25-28 kDa and 59-60 kDa. These results indicate the possible role of the above proteins (25-28 kDa and 59-60 kDa) in the viral binding to the hepatocytes.