VH3-53/66-Class RBD-Specific Human Monoclonal Antibody iB20 Displays Cross-Neutralizing Activity against Emerging SARS-CoV-2 Lineages

Abstract

Immune evasion of SARS-CoV-2 undermines current strategies tocounteract the pandemic, with the efficacy of therapeutic virus-neutralizing monoclonal antibodies (nAbs) being affected the most. In this work, we asked whether two previously identified human cross-neutralizing nAbs, iB14 (class VH1-58) and iB20 (class VH3-53/66), are capable of neutralizing the recently emerged Omicron (BA.1) variant. Both nAbs were found to bind the Omicron RBD with a nanomolar affinity, yet they displayed contrasting functional features. When tested against Omicron, the neutralizing activity of iB14 was reduced 50-fold, whereas iB20 displayed a surprising increase in activity. Thus, iB20 is a unique representative of the VH3-53/66-class of nAbs in terms of breadth of neutralization, which establishes it as a candidate for COVID-19 therapy and prophylactics.

Serial Llama Immunization with Various SARS-CoV-2 RBD Variants Induces Broad Spectrum Virus-Neutralizing Nanobodies

“…Neutralization assays for H5, G7, 2F4, and their Fc fusions were conducted in the same way as described by Gorchakov et al [ 21 ]. For 9A7, 9A21, 9A57, and 9A58, their Fc fusions, 9A4 and 9A80, a modified version of the assay was used [ 22 ]. 48 h following transduction of the ACE2-HEK293N cells with a mixture of antibody and S-pseudotyped lentivirus, the cells were washed with PBS and lysed in PBS with 0.2% Triton X-100.…”

“…Earlier, we described a panel of highly potent monoclonal human antibodies that neutralized the Wuhan variant of SARS-CoV-2 and several early coronavirus variants [ 21 , 22 ]. As a parallel research direction, we also investigated the properties of SARS-CoV-2-specific llama nanobodies.…”

A potent, broadly neutralizing human monoclonal antibody that efficiently protects hACE2-transgenic mice from infection with the Wuhan, BA.5, and XBB.1.5 SARS-CoV-2 variants

“…The constructs encoding wild-type and mutant variants of the Spike protein were obtained either via gene synthesis (Genewiz, USA; NovoPro Bioscience, China; Evrogen, Russia) or PCR mutagenesis with sets of mutagenic primers ( 33 ). A Spike-pseudotyped lentivirus neutralization assay was performed as described ( 19 ). Briefly, ACE2-HEK293T cells were transduced with a mixture of the antibody and the Spike-pseudotyped lentiviral particles; 48 hours later, the cells were washed, lysed, and luminescence intensity upon the addition of the substrate (1.25 µg of freshly prepared h-coelenterazine (Nanolight Technologies, Germany) in 50 µL of PBS per well, 3 s) was measured.…”

“…We previously reported the isolation of a panel of monoclonal antibodies capable of neutralizing the Wuhan-1 variant of SARS-CoV-2 with ultrahigh potency ( 18 ). Of these, one was shown to neutralize both the early viral variants and the Omicron variant BA.1–BA.4/5 ( 19 ). In the present study, we set out to isolate SARS-CoV-2-neutralizing antibodies that have a broader range using an individual with hybrid antiviral immunity as the source of B cells ( Figure 1A ).…”

Hybrid Immunity from Gam-COVID-Vac Vaccination and Natural SARS-CoV-2 Infection Confers Broader Neutralizing Activity against Omicron Lineage VOCs Than Revaccination or Reinfection

“…We previously reported the isolation of a panel of human monoclonal antibodies displaying highly potent neutralization of the Wu-1 variant of the virus [ 7 ]. One antibody from this panel showed high activity against early omicron variants [ 8 ], but none of them neutralized BQ.1.1, XBB, or XBB.1.5. Therefore, a deeper understanding of how broad immunity may be formed would be valuable for improving vaccination strategies and guiding identification of next-generation, pan-sarbecovirus therapeutic antibodies.…”