Anti-Hepatitis C, E2 (Clone HEPC-74) - Purified No Carrier Protein (H311-GRP)

Hepatitis C (HCV) is a flavivirus that annually infects an estimated 58 million people worldwide, causing liver failure and cancer 1. HCV has two surface glycoproteins, E1 and E2, that associate to form a heterodimer, E1E2, on the surface of the virion. E1 is thought to function in viral-host membrane fusion during entry, whereas E2 is known to interact with the cellular entry receptors tetraspanin CD81, scavenger receptor-B1, occludin, and claudin. E1 and E2 are single-pass transmembrane proteins that do not share sequence or structural similarity with other flavivirus type II fusion glycoproteins. Both E1 and E2 are heavily glycosylated. HEPC-74 was generated by screening donor plasma from patients who had spontaneously cleared HCV infection for HCV-neutralizing antibodies using a panel of 19 genotype 1a and 1b HCV pseudoparticles 2. Plasma taken just before infection clearance was used in the screening. Peripheral blood mononuclear cells from serum obtained after clearance were then isolated, and B-cells were transformed with EBV, CpG and supplements, cultured, and screened for neutralizing activity against autologous and heterologous HCV variants. Cells capable of neutralizing HCV were fused with HMMA2.5 myeloma cells for hybridoma production and screened against HCV E1E2 heterodimer. The resulting monoclonal antibodies were then purified and tested for neutralizing breadth against the original 19 genotype panel. HEPC-74 was found to neutralize 17/19 variants. Additionally, HEPC-74 neutralized all except genotype 3 in a panel of genotype 1-6 replication-competent cell culture viruses. HEPC-74 binds to a conserved, conformational epitope in the front layer of E2 2 near N-linked glycans at positions N430 and N448 1. HEPC-74 recognizes E2 using a disulfide-linked CDRH3 motif and predominantly binds V H domain residues 3. HEPC-74 blocks CD81 binding to E1E2 due to overlapping binding sites 1,3,4. HEPC-74 blocks HCV entry at an early post-attachment step, before claudin engagement 4. HEPC-74 binds native E1E2 but not denatured protein 2. HEPC-74 is a neutralizing antibody 4 that can be useful in cryo-EM mapping of E1E2 1.