Development of Multivalent Nanobodies Blocking SARS CoV 2 Infection by Targeting RBD of Spike Protein

Abstract

Background: The outbreak and pandemic of coronavirus SARS CoV 2 caused significant threaten to global public health and economic consequences. It is extremely urgent that global people must take actions to develop safe and effective preventions and therapeutics. Nanobodies, which are derived from single‑chain camelid antibodies, had shown antiviral properties in various challenge viruses. In this study, multivalent nanobodies with high affinity blocking SARS CoV 2 spike interaction with ACE2 protein were developed.Results: Totally, four specific nanobodies against spike protein and its RBD domain were screened from a naïve VHH library. Among them, Nb91 hFc and Nb3 hFc demonstrated antiviral activity by neutralizing spike pseudotyped viruses in vitro. Subsequently, multivalent nanobodies were constructed to improve the neutralizing capacity. As a result, heterodimer nanobody Nb91 Nb3 hFc exhibited the strongest RBD binding affinity and neutralizing ability against SARS CoV 2 pseudoviruses with an IC50 value at approximately 1.54 nM. Conclusions: The present study indicated that naïve VHH library could be used as a potential resource for rapid acquisition and exploitation of antiviral nanobodies. Heterodimer nanobody Nb91 Nb3 hFc may serve as a potential therapeutic agent for the treatment of COVID 19.

Dynamic landscape mapping of humoral immunity to SARS-CoV-2 identifies non-structural protein antibodies associated with the survival of critical COVID-19 patients

“…Two specific nanobodies, Nb91-hFc and Nb3-hFc, demonstrated antiviral activity by neutralizing SARS-CoV-2 pseudoviruses in vitro. 60 Another nanobody produced by a naïve llama single-domain antibody library and PCR-based maturation showed neutralizing activity against live SARS-CoV-2. 61 Our data may help direct the development of nanobodies targeting nsps for COVID-19 therapy.…”

Comprehensive Deep Mutational Scanning Reveals the Immune-Escaping Hotspots of SARS-CoV-2 Receptor-Binding Domain Targeting Neutralizing Antibodies

“…Thus, RBD determines the transmissibility and infectivity of the virus, and all vaccines under development directly target it. Moreover, neutralizing antibodies have been developed against SARS-CoV-2 (Jiang et al, 2020;Pinto et al, 2020;Rogers et al, 2020;Xiaojie et al, 2020;Lau et al, 2021;Liu et al, 2021;Lu et al, 2021). However, RBD mutations can The heatmap of interactive residues of RBD derived from the calculated mutational binding stabilities by using Discovery Studio 3.5 (DS), Mutabind2, FoldX, and mCSM-PPI2.…”

“…The S protein is immunogenic; hence, several approaches have targeted it for viral neutralization. Neutralizing antibodies targeting RBD have also been developed (Pinto et al, 2020;Rogers et al, 2020;Xiaojie et al, 2020;Liu et al, 2021;Lu et al, 2021). Some antibody-based antiviral therapeutics have demonstrated high specificity, potency, and modularity.…”

Therapeutic Potential of Exploiting Autophagy Cascade Against Coronavirus Infection

“…In the long run, therefore we need more than one vaccine ensuring an unbiased global access particularly in the underdeveloped countries, protection of diverse population of different ethnic background as well as immunity against multiple viral strains. In addition to boost host innate immunity, among various strategies employed, passive immunotherapy using camelidderived single domain antibody fragments, also known as VHH or nanobodies, are of great interest for the treatment and prevention of COVID-19 (Hanke et al, 2020;Lu et al, 2021). Although retaining specificity and affinity, due to their substantial smaller size, around one tenth of the conventional antibodies, nanobodies possess several advantages, like easy manipulation, cloning, express in bacteria in large quantities along with a number of favourable biochemical properties, including high thermostability and deep tissue penetration (Hanke et al, 2020;Koenig et al, 2021).…”