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-CoV-2), has affected nearly every aspect of life worldwide, claiming the lives of over 3.9 million people globally, at the time of this publication. Neutralizing humanized nanobody (V H H)-based antibodies (V H H-huFc) represent a promising therapeutic intervention strategy to address the current SARS-CoV-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-huFc antibodies were identified and evaluated for their capacity to tightly bind to the SARS-CoV-2 receptor-binding domain, to prevent binding of SARS-CoV-2 spike (S) to the cellular receptor angiotensin-converting enzyme 2, and to neutralize viral infection. Preliminary preclinical evaluation of multiple V H H-huFc antibody candidates demonstrate that they are prophylactically and therapeutically effective in vivo against wildtype SARS-CoV-2. The identified and characterized V H H-huFc antibodies described herein represent viable candidates for further preclinical evaluation and another tool to add to our therapeutic arsenal to address the COVID-19 pandemic.

Structural Insights into the Design of Synthetic Nanobody Libraries

“…The most common strategy in the design of the hypervariable regions is to leave CDR1 and CDR2 at a fixed length each, whereas CDR3 may be represented by several different lengths, especially in the most recently reported libraries [ 12 , 13 , 14 , 15 , 17 , 18 , 19 , 20 , 22 , 23 ]. In most cases, the variability of CDRs 1 and 2 is set to represent the amino acid variability found in natural Nb repertoires.…”

“…That is why the number of Nb binders and their affinity values are generally higher in immune libraries [ 7 ]. However, recent works have shown that synthetic libraries can yield high affinity Nbs against different antigens, comparable to those obtained from immune libraries [ 12 , 14 , 20 , 22 ].…”

“…Given the variability and non-specificity of synthetic libraries, the chances of obtaining high affinity Nbs are in principle lower. Nonetheless, recent studies have reported Nbs, selected from synthetic libraries, with affinities in the nanomolar range [ 12 , 14 , 20 , 22 ] and even in the subnanomolar order [ 12 , 14 , 20 ]. In addition, the affinity of a selected Nb may be further improved by an in vitro maturation process [ 15 , 62 ].…”

Bovine-derived antibodies and camelid-derived nanobodies as biotherapeutic weapons against SARS-CoV-2 and its variants: A review article

“…Synthetic nanobodies (sybodies) are small, aerosolizeable, and heat stable, making them a viable candidate for COVID-19 prevention and treatment [ 79 ]. Stefan et al [ 118 ] created a massive synthetic VHH library (3.18 × 10 10 ) and identified more than 50 VHH candidates that can bind to SARS-2 [ 6 ]. Schoof et al [ 119 ] used a synthetic Nbs library to identify a panel of Nbs that can bind to multiple epitopes on Spike.…”

The Response of the Muslim Community in Indonesia when Lockdown was Reimplemented

“…The dire results have come despite ambitious and comprehensive response measures; at least on paper, the strict pattern of action has failed to mitigate the impact of this pandemic (Cabana et al, 2021). Then the situation was tense again when COVID-19 mutated from the novel Coronavirus (for example, the Delta and Kappa variants), which became an additional threat for the upcoming season in various countries (Stefan et al, 2021), including Indonesia, which was confirmed in June 2021 (Hasibuan, 2021). Therefore, this public health emergency requires more than just a health and medical care response, requiring the involvement of all citizens, targeted action from governments at all levels, and the implementation of multi-stakeholder policies (Bernard et al, 2021).…”