Hepatitis C virus envelope glycoproteins E1 and E2 (E1/E2)

The Hepatitis C virus (HCV) envelope glycoproteins E1 and E2 are the primary structural proteins located on the surface of the HCV virion, where they assemble as a non-covalent heterodimer. These glycoproteins are essential for viral entry into hepatocytes, a process involving sequential interactions with host cell receptors such as CD81, scavenger receptor class B type I (SR-BI), claudin-1, and occludin. E2 is the major receptor-binding protein, while E1 is believed to facilitate the fusion of the viral membrane with the host endosomal membrane, although the two proteins function cooperatively as a single unit. Because they are the only viral proteins exposed to the host immune system, the E1/E2 complex is the principal target for neutralizing antibodies and the primary focus of prophylactic vaccine development. Therapeutic interventions under investigation include broadly neutralizing monoclonal antibodies (e.g., HCV1), entry-inhibiting peptides (e.g., Peptide 75, E27), and small molecules like flunarizine that interfere with the fusion process. However, the development of effective therapies is significantly hindered by the virus's high genetic diversity, the presence of hypervariable regions (HVR1) that act as immunological decoys, and a dense glycan shield that masks conserved epitopes.

Other names

E1E2gp35gp70HCV envelope proteinsE1E2 complexE1E2 heterodimer

Inhibition of viral entry by blocking attachment to host receptors (e.g., CD81, SR-BI), interfering with post-attachment steps, or preventing membrane fusion between the viral envelope and the host endosomal membrane.