DOI: 10.3390/biomedicines12030642 ISSN: 2227-9059

Broad Epitope Coverage of Therapeutic Multi-Antibody Combinations Targeting SARS-CoV-2 Boosts In Vivo Protection and Neutralization Potency to Corner an Immune-Evading Virus

Ilse Roodink, Maartje van Erp, Andra Li, Sheila Potter, Sander M. J. van Duijnhoven, Milou Smits, Arthur J. Kuipers, Bert Kazemier, Bob Berkeveld, Ellen van Geffen, Britte S. de Vries, Danielle Rijbroek, Bianca Boers, Sanne Meurs, Wieger Hemrika, Alexandra Thom, Barry N. Duplantis, Roland A. Romijn, Jeremy S. Houser, Jennifer L. Bath, Yasmina N. Abdiche
  • General Biochemistry, Genetics and Molecular Biology
  • Medicine (miscellaneous)

Therapeutic antibodies (Abs) which act on a broader range of epitopes may provide more durable protection against the genetic drift of a target, typical of viruses or tumors. When these Abs exist concurrently on the targeted antigen, several mechanisms of action (MoAs) can be engaged, boosting therapeutic potency. This study selected combinations of four and five Abs with non- or partially overlapping epitopes to the SARS-CoV-2 spike glycoprotein, on or outside the crucial receptor binding domain (RBD), to offer resilience to emerging variants and trigger multiple MoAs. The combinations were derived from a pool of unique-sequence scFv Ab fragments retrieved from two SARS-CoV-2-naïve human phage display libraries. Following recombinant expression to full-length human IgG1 candidates, a biolayer interferometric analysis mapped epitopes to bins and confirmed that up to four Abs from across the bins can exist simultaneously on the spike glycoprotein trimer. Not all the bins of Abs interfered with the spike protein binding to angiotensin converting enzyme 2 (ACE2) in competitive binding assays, nor neutralized the pseudovirus or authentic virus in vitro, but when combined in vivo, their inclusion resulted in a much stronger viral clearance in the lungs of intranasally challenged hamsters, compared to that of those treated with mono ACE2 blockers. In addition, the Ab mixtures activated in vitro reporter cells expressing Fc-gamma receptors (FcγRs) involved in antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP). The best four-Ab combination neutralized seventeen variants of concern from Wuhan-Hu1 to Omicron BA.4/BA.5 in vitro.

More from our Archive