A novel bispecific antibody dual-targeting approach for enhanced neutralization against fast-evolving SARS-CoV-2 variants

Front Immunol. 2023 Sep 26:14:1271508. doi: 10.3389/fimmu.2023.1271508. eCollection 2023.

Abstract

Introduction: The emergence of new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants has caused unprecedented health and socioeconomic crises, necessitating the immediate development of highly effective neutralizing antibodies. Despite recent advancements in anti-SARS-CoV-2 receptor-binding domain (RBD)-specific monoclonal antibodies (mAbs) derived from convalescent patient samples, their efficacy against emerging variants has been limited. In this study, we present a novel dual-targeting strategy using bispecific antibodies (bsAbs) that specifically recognize both the SARS-CoV-2 RBD and fusion peptide (FP), crucial domains for viral attachment to the host cell membrane and fusion in SARS-CoV-2 infection.

Methods: Using phage display technology, we rapidly isolated FP-specific mAbs from an established human recombinant antibody library, identifying K107.1 with a nanomolar affinity for SARS-CoV-2 FP. Furthermore, we generated K203.A, a new bsAb built in immunoglobulin G4-(single-chain variable fragment)2 forms and demonstrating a high manufacturing yield and nanomolar affinity to both the RBD and FP, by fusing K102.1, our previously reported RBD-specific mAb, with K107.1.

Results: Our comprehensive in vitro functional analyses revealed that the K203.A bsAb significantly outperformed the parental RBD-specific mAb in terms of neutralization efficacy against SARS-CoV-2 variants. Furthermore, intravenous monotherapy with K203.A demonstrated potent in vivo neutralizing activity without significant in vivo toxicity in a mouse model infected with a SARS-CoV-2 variant.

Conclusion: These findings present a novel bsAb dual-targeting strategy, directed at SARS-CoV-2 RBD and FP, as an effective approach for rapid development and management against continuously evolving SARS-CoV-2 variants.

Keywords: SARS-CoV-2; bispecific antibody; fusion peptide; phage display; receptor-binding domain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Bispecific* / therapeutic use
  • Antibodies, Neutralizing
  • Antibodies, Viral
  • COVID-19*
  • Humans
  • Mice
  • SARS-CoV-2

Substances

  • Antibodies, Bispecific
  • Antibodies, Neutralizing
  • Antibodies, Viral

Supplementary concepts

  • SARS-CoV-2 variants

Grants and funding

The authors declare financial support was received for the research, authorship, and/or publication of this article. This research was supported by the Bio & Medical Technology Development Program of the National Research Foundation of Korea (grant numbers: NRF-2019M3E5D5065844 and NRF-2020M3A9I2107093) and the Korea Health Technology R&D Project of the Korea Health Industry Development Institute (grant number: HI22C0360) funded by the Korean government.