Development of Potent and Effective Synthetic SARS-CoV-2 Neutralizing Nanobodies

Abstract

The respiratory virus responsible for Coronavirus disease 2019 (COVID-19), Severe acute respiratory syndrome coronavirus 2 (SARS-2), has impacted nearly every aspect of life worldwide, claiming the lives of over 2.5 million people globally, at the time of this publication. Neutralizing nanobodies (V H H) represent a promising therapeutic intervention strategy to address the current SARS-2 pandemic and provide a powerful toolkit to address future virus outbreaks. Using a synthetic, high-diversity V H H bacteriophage library, several potent neutralizing V H H antibodies were identified and evaluated for their capacity to tightly bind to the SARS-2 receptor-binding domain (RBD), to prevent binding of SARS-2 spike (S) to the cellular receptor Angiotensin-converting enzyme 2 (ACE2), and to neutralize viral infection. Preliminary preclinical evaluation of multiple nanobody candidates demonstrate that they are prophylactically and therapeutically effective in vivo against wildtype SARS-2. The identified and characterized nanobodies described herein represent viable candidates for further preclinical evaluation and another tool to add to our therapeutic arsenal to address the COVID-19 pandemic.

Differential laboratory passaging of SARS-CoV-2 viral stocks impacts the in vitro assessment of neutralizing antibodies

“…In this and other studies (9,33) the error prone RNA dependent RNA polymerase of the VSV genome enabled rapid generation of escape mutations. Although the mutation rate of SARS-CoV-2 is lower than that of other RNA viruses such as VSV that lack the 3U exonuclease proofreading mechanism found in coronaviruses (34), the escape mutants observed by this and other studies reflect mutations detected in natural infections (9,33). This can be explained by the large viral populations generated in natural infections and the enormous scope of the CoVID-19 pandemic.…”