Bispecific VH/Fab antibodies targeting neutralizing and non-neutralizing Spike epitopes demonstrate enhanced potency against SARS-CoV-2. Issue 1 (1st January 2021)

• Record Type: Journal Article
• Authors: Lim, Shion A.; Gramespacher, Josef A.; Pance, Katarina; Rettko, Nicholas J.; Solomon, Paige; Jin, Jing; Lui, Irene; Elledge, Susanna K.; Liu, Jia; Bracken, Colton J.; Simmons, Graham; Zhou, Xin X.; Leung, Kevin K.; Wells, James A.
• Is Part Of: MAbs. Volume 13:Issue 1(2021)
• Publication Date: 2021-01-01
• Subjects: Bispecific -- neutralizing antibody -- knob-in-hole -- COVID-19 -- SARS-CoV-2; Monoclonal antibodies -- Therapeutic use -- Periodicals; Monoclonal antibodies -- Periodicals; Antibodies, Monoclonal -- Periodicals; 616.0798
• DOI: 10.1080/19420862.2021.1893426
• Languages: English
• ISSNs: 1942-0862

Abstract

ABSTRACT: Numerous neutralizing antibodies that target SARS-CoV-2 have been reported, and most directly block binding of the viral Spike receptor-binding domain (RBD) to angiotensin-converting enzyme II (ACE2). Here, we deliberately exploit non-neutralizing RBD antibodies, showing they can dramatically assist in neutralization when linked to neutralizing binders. We identified antigen-binding fragments (Fabs) by phage display that bind RBD, but do not block ACE2 or neutralize virus as IgGs. When these non-neutralizing Fabs were assembled into bispecific VH/Fab IgGs with a neutralizing VH domain, we observed a ~ 25-fold potency improvement in neutralizing SARS-CoV-2 compared to the mono-specific bi-valent VH-Fc alone or the cocktail of the VH-Fc and IgG. This effect was epitope-dependent, reflecting the unique geometry of the bispecific antibody toward Spike. Our results show that a bispecific antibody that combines both neutralizing and non-neutralizing epitopes on Spike-RBD is a promising and rapid engineering strategy to improve the potency of SARS-CoV-2 antibodies.