Breadth of neutralization and synergy of clinically relevant human monoclonal antibodies against HCV genotypes 1a, 1b, 2a, 2b, 2c, and 3a

Abstract

Human monoclonal antibodies (HMAbs) with neutralizing capabilities constitute potential immune-based treatments or prophylaxis against hepatitis C virus (HCV). However, lack of cell culture-derived HCV (HCVcc) harboring authentic envelope proteins (E1/E2) has hindered neutralization investigations across genotypes, subtypes, and isolates. We investigated the breadth of neutralization of 10 HMAbs with therapeutic potential against a panel of 16 JFH1-based HCVcc expressing patient-derived Core-NS2 from genotypes 1a (strains H77, TN, and DH6), 1b (J4, DH1, and DH5), 2a (J6, JFH1, and T9), 2b (J8, DH8, and DH10), 2c (S83), and 3a (S52, DBN, and DH11). Virus stocks used for in vitro neutralization analysis contained authentic E1/E2, with the exception of full-length JFH1 that acquired the N417S substitution in E2. The 50% inhibition concentration (IC50) for each HMAb against the HCVcc panel was determined by dose-response neutralization assays in Huh7.5 cells with antibody concentrations ranging from 0.0012 to 100 μg/ml. Interestingly, IC50-values against the different HCVcc’s exhibited large variations among the HMAbs, and only three HMAbs (HC-1AM, HC84.24, and AR4A) neutralized all 16 HCVcc recombinants. Furthermore, the IC50-values for a given HMAb varied greatly with the HCVcc strain, which supports the use of a diverse virus panel. In cooperation analyses, HMAbs HC84.24, AR3A, and, especially HC84.26, demonstrated synergistic effects towards the majority of the HCVcc’s when combined individually with AR4A. Conclusion: Through a neutralization analysis of 10 clinically relevant HMAbs against 16 JFH1-based Core-NS2 recombinants from genotypes 1a, 1b, 2a, 2b, 2c, and 3a, we identified at least 3 HMAbs with potent and broad neutralization potential. The neutralization synergism obtained when pooling the most potent HMAbs could have significant implications for developing novel strategies to treat and control HCV.

Hepatitis C virus resistance to broadly neutralizing antibodies measured using replication-competent virus and pseudoparticles

“…S1). Of note, IC 50 s measured for H77 HCVcc and S52 HCVcc with bNAbs CBH-5, HC33.4, HC84.26 and AR3A were all consistent with values measured in a previously published study (Carlsen et al, 2014). As has been shown in prior publications (Bailey et al, 2015a;Keck et al, 2009;Wasilewski et al, 2016), relative resistance of HCVcc variants to most bNAbs Table 1, and all neutralization curves are shown in Fig.…”

“…These HCVcc have been used to further define viral entry pathways (Brimacombe et al, 2011;Carlsen et al, 2013;Mathiesen et al, 2015;Timpe et al, 2008) and to show that broadly neutralizing monoclonal antibodies (bNAbs) can prevent HCV infection in animal models (Forns et al, 2000;Morin et al, 2012;Youn et al, 2005). Panels of HCVcc expressing E1E2 from multiple genotypes have also been used to measure neutralizing breadth of bNAbs (Carlsen et al, 2014;Keck et al, 2008Keck et al, , 2013Law et al, 2008).…”

Naturally selected hepatitis C virus polymorphisms confer broad neutralizing antibody resistance

“…However, we show for the first time that all of these mAbs, except nonneutralizing mAb CBH-4B, segregate into only 3 distinct neutralization clusters. This suggests that resistance polymorphisms outside of known epitopes may confer resistance to many anti-HCV human mAbs, including some of the most broadly neutraliz- neutralization clustering, as it showed synergistic neutralization by a combination of mAbs, HC84.26 and AR4A, which we have identified as NC1 and NC2 mAbs, respectively, in this study (35). Increasing evidence suggests that mutations outside of known binding epitopes may confer resistance to anti-HCV mAbs.…”

“…Increasing evidence suggests that mutations outside of known binding epitopes may confer resistance to anti-HCV mAbs. The Carlsen study found no correlation between variation in mapped mAb epitopes and mAb resistance (35). In addition, studies by Keck et al (14) and Fofana et al (36) described mutations arising in single HCV-infected subjects that fell outside of known mAb-binding epitopes and conferred relative resistance to multiple anti-HCV mAbs.…”

A Hepatitis C Virus Envelope Polymorphism Confers Resistance to Neutralization by Polyclonal Sera and Broadly Neutralizing Monoclonal Antibodies

“…Infusion of bNAbs is protective against infection in animal models of HCV (22, 31), and early high-titer bNAb responses to HCV are associated with viral clearance in humans (3,10,(32)(33)(34)(35). Unfortunately, resistance to bNAbs can also develop, and multiple studies have demonstrated that this resistance sometimes results from mutations distant from bNAb binding sites (11,(36)(37)(38). Since bNAbs may serve as a guide for HCV vaccine development, a more comprehensive understanding of resistance to bNAbs is essential.…”