Hepatitis C virus E1-E2 envelope glycoprotein complex (HCV E1-E2)

The E1-E2 envelope glycoprotein complex is a non-covalently linked heterodimer that serves as the primary surface component of the Hepatitis C Virus (HCV) [4, 6]. It is composed of two subunits: E2, which functions as the primary receptor-binding protein by interacting with host factors like CD81 and SR-BI, and E1, which is thought to mediate the fusion between the viral envelope and the host cell membrane [1, 10, 16]. This complex is the sole target for broadly neutralizing antibodies (bNAbs) and is the focal point for prophylactic vaccine development aimed at preventing HCV infection [2, 12]. Developing therapeutics against E1-E2 is exceptionally challenging due to the virus's extreme sequence variability and the presence of a glycan shield that protects critical epitopes from immune recognition [5, 12]. While Direct-Acting Antivirals (DAAs) target non-structural proteins to treat existing infections, E1-E2 remains the essential target for generating long-term immunity and preventing transmission [3, 12]. Recent structural insights using cryo-electron microscopy have provided a blueprint for the rational design of next-generation immunogens that better mimic the native viral surface [5, 7, 11].

Other names

HCV E1/E2 heterodimerE1E2 complexHepatitis C virus envelope glycoproteinsgpE1/gpE2 complexEnvelope glycoprotein E1Envelope glycoprotein E2

Drugs targeting the E1-E2 complex primarily function as entry inhibitors by blocking the interaction between the viral E2 protein and host cell receptors such as CD81 and scavenger receptor class B type I (SR-BI) [1, 6, 12]. Neutralizing antibodies may also interfere with the conformational changes required for membrane fusion, which is largely mediated by the E1 subunit, or aggregate virions to prevent attachment [10, 13, 15].