Biology subjects

Zon, I.

Publications and source records attributed to Zon, I..

3 recordsLinked to original sources

bioRxiv2026

Consensus native-like hepatitis C virus E1E2 engages broadly neutralizing antibody precursors

A major goal for hepatitis C virus (HCV) vaccine development is to elicit broadly neutralizing antibodies (bNAbs) against the E1E2 glycoprotein complex located on the viral surface. Inducing HCV bNAbs requires engagement of their germline B cell precursors. HCV glycoproteins usually do not bind and activate inferred germline precursors of bNAbs (igl-bNAbs), possibly because most circulating strains contain non-conserved isolate-specific residues, even in bNAb epitopes. Here, we generated stabilized native-like soluble E1E2 (sE1E2) antigens based on a consensus sequence of HCV (HepCon) to limit the exposure of antigenically rare residues. The antigenicity and glycosylation profiles show that HepCon sE1E2 resembles a native-like E1E2 heterodimer. HepCon sE1E2 induced cross-reactive neutralizing antibody responses as a soluble protein immunogen and as membrane-anchored mRNA-delivered immunogen in animals. Importantly, HepCon sE1E2 engages multiple igl-bNAbs against two major epitopes: antigenic region 3 (AR3), which is targeted by igl-bNAbs derived from the widely expressed human VH1-69 B cell gene, and antigenic region 4 (AR4), which is only present on native-like E1E2. Nanoparticles with HepCon sE1E2 efficiently activated B cell lines expressing AR3 and AR4 igl-bNAb B cell receptors in vitro. Finally, using HepCon sE1E2 we elucidated the atomic contacts of an AR3 igl-bNAb by cryo-electron microscopy. Thus, HepCon sE1E2 is a promising candidate for germline-targeting vaccination strategies.

immunology↗

bioRxiv2024

Bispecific antibodies against the hepatitis C virus E1E2 envelope glycoprotein

Hepatitis C virus (HCV) currently causes about one million infections and 240,000 deaths worldwide each year. To reach the goal set by the World Health Organization (WHO) of global HCV elimination by 2030, it is critical to develop a prophylactic vaccine. Broadly neutralizing antibodies (bNAbs) target the E1E2 envelope glycoproteins on the viral surface, can neutralize a broad range of the highly diverse circulating HCV strains and are essential tools to inform vaccine design. However, bNAbs targeting a single E1E2 epitope might be limited in neutralization breadth, which can be enhanced by using combinations of bNAbs that target different envelope epitopes. We have generated 60 IgG-like bispecific antibodies (bsAbs) that can simultaneously target two distinct epitopes on E1E2. We combine non-overlapping E1E2 specificities into three types of bsAbs, each containing a different hinge length. The bsAbs show retained or increased potency and breadth against a diverse panel of HCV pseudoparticles (HCVpp) and HCV produced in cell culture (HCVcc) compared to monospecific and cocktail controls. Additionally, we demonstrate that changes in the hinge length of bsAbs can alter the binding stoichiometry to E1E2. These results provide insights into the binding modes and the role of avidity in bivalent targeting of diverse E1E2 epitopes, and suggest structural differences between HCVpp and HCVcc. This study illustrates how potential cooperative effects of HCV bNAbs can be utilized by strategically designing bispecific constructs. These new HCV bsAbs can guide vaccine development and unlock novel therapeutic and prophylactic strategies against HCV and other (flavi)viruses.

microbiology↗

bioRxiv2021

Structure of the hepatitis C virus E1E2 glycoprotein complex

Hepatitis C virus (HCV) infection is a leading cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma in humans, and afflicts more than 58 million people worldwide. The HCV envelope E1 and E2 glycoproteins are essential for viral entry and infection, and comprise the primary antigenic target for neutralizing antibody responses. The molecular mechanisms of E1E2 assembly, as well as how the E1E2 heterodimer binds broadly neutralizing antibodies, remains elusive. We present the cryo-electron microscopy (cryoEM) structure of the membrane-extracted full-length E1E2 heterodimer in complex with broadly neutralizing antibodies (bNAbs) AR4A, AT12009 and IGH505 at [~]3.5 [A] resolution. We resolve the long sought-after interface between the E1 and E2 ectodomains and reveal how it is stabilized by hydrophobic interactions and glycans. This structure deepens our understanding of the HCV fusion glycoprotein and delivers a blueprint for the rational design of novel vaccine immunogens and anti-viral drugs.

immunology↗