Binding of Hepatitis C Virus to CD81

TLDR

Chronic hepatitis C virus infection affects about 3 % of the global population, is a leading cause of liver disease, is linked to cryoglobulinemia, and its cell‑entry mechanisms remain poorly understood. The HCV envelope protein E2 binds the major extracellular loop of the tetraspanin CD81, which is expressed on hepatocytes and B lymphocytes. E2 binds the CD81 extracellular loop, and recombinant loop proteins bind HCV while neutralizing antibodies that block infection in vivo inhibit this binding in vitro.

Abstract

Chronic hepatitis C virus (HCV) infection occurs in about 3 percent of the world's population and is a major cause of liver disease. HCV infection is also associated with cryoglobulinemia, a B lymphocyte proliferative disorder. Virus tropism is controversial, and the mechanisms of cell entry remain unknown. The HCV envelope protein E2 binds human CD81, a tetraspanin expressed on various cell types including hepatocytes and B lymphocytes. Binding of E2 was mapped to the major extracellular loop of CD81. Recombinant molecules containing this loop bound HCV and antibodies that neutralize HCV infection in vivo inhibited virus binding to CD81 in vitro.