Proof of concept for rational design of hepatitis C virus E2 core nanoparticle vaccines

Abstract

Hepatitis C virus (HCV) envelope glycoproteins E1 and E2 are responsible for cell entry, with E2 being the major target of neutralizing antibodies (NAbs). Here, we present a comprehensive strategy for B cell–based HCV vaccine development through E2 optimization and nanoparticle display. We redesigned variable region 2 in a truncated form (tVR2) on E2 cores derived from genotypes 1a and 6a, resulting in improved stability and antigenicity. Crystal structures of three optimized E2 cores with human cross-genotype NAbs (AR3s) revealed how the modified tVR2 stabilizes E2 without altering key neutralizing epitopes. We then displayed these E2 cores on 24- and 60-meric nanoparticles and achieved substantial yield and purity, as well as enhanced antigenicity. In mice, these nanoparticles elicited more effective NAb responses than soluble E2 cores. Next-generation sequencing (NGS) defined distinct B cell patterns associated with nanoparticle-induced antibody responses, which target the conserved neutralizing epitopes on E2 and cross-neutralize HCV genotypes.

Single-component multilayered self-assembling nanoparticles presenting rationally designed glycoprotein trimers as Ebola virus vaccines

“…Namely, the redesigned GP∆muc trimer activated more VH/VL genes (9.4/9.4) than its NP form (6/7), with P values of 0.0163 and 0.0076 for VH and VL, respectively. In contrast, the E2p NP decorated with 60 HCV E2 cores activated more VH, but not VL, genes than the E2 core (65).…”

“…5B, bottom). This finding was somewhat unexpected, as significant differences were found between soluble E2 core and NP groups at both w2 and w5 in a recent HCV vaccine study (65), suggesting that antibody titers of antigen-presenting NPs may be influenced by antigen size, structure, and epitope distribution. NP display may occlude antibody access to the base and stalk epitopes, which are the targets of many bNAbs (9).…”

“…Previously, we displayed HIV-1 Env trimers on 24-and 60-meric NPs, which elicited tier-2 NAb responses more effectively than trimers in mice and rabbits (55,64). We also reported NPs presenting an optimized HCV E2 core and demonstrated cross-genotype NAb responses in mice (65). Here, we tested these protein NPs as "multivalent carriers" to display redesigned GP∆muc trimers for in vivo assessment.…”

“…5F) in the ebolavirus-pp assay. Immunoglobulin G (IgG) was purified from the mouse serum at the last time point (w11) to eliminate non-specific, anti-viral activities (55,65). Distinct patterns of antibody response were observed, suggesting the elicitation of NAbs and c13C6-like non-NAbs.…”

“…Previously, we combined antigen-specific B cell sorting and NGS to obtain a quantitative readout of B cell responses induced by HCV E2 core (E2mc3) and E2mc3-E2p NP (65). Diverse heavychain variable gene (VH) usage, a higher degree of VH mutations, and a broader range of heavy chain complementarity determining region 3 (HCDR3) length were observed for E2p, alluding to 477 a common B cell mechanism for NP vaccines (65). In this study, we applied the same strategy to 478 obtain GP-specific B cell profiles for different EBOV vaccines (Fig.…”