Nanobodies, the potent agents to detect and treat the Coronavirus infections: A systematic review

Abstract

The newly emerged coronavirus (SARS-CoV-2) continues to infect humans, and no effective treatment has yet been found. Antibody therapy is one way to control infection caused by COVID-19. However, the use of classical antibodies raises complex issues. Heavy chain antibodies (HCAbs) are single-domain antibodies derived from the Camelidae family. The variable part of these antibodies (Nanobodies or VHH) has interesting properties such as small size, cost-effective production, and good tissue permeability, causing VHH to be regarded as an antiviral therapeutics. However, the small size of nanobodies may lead to low antigen binding affinity and rapid renal clearance. In this systematic review, the application of nanobodies in the treatment of COVID-19 infection and other similar infections (MERS and SARS) was reviewed.

Keywords: COVID-19; Nanobodies; SARS-CoV-2; VHH.

Fig. 1

A schematic picture of nanobody mechanisms. (a) By binding nanobodies to a localization signal (LS), the protein of interest (POI) can be enriched at a specific cellular site, such as mitochondria, (b) Nanobodies can perform a direct inhibitory effect and prevent from a protein activity, (c) Nanobodies can be used to target a for enzymatic degradation, (d) Fusion between the nanobody and the fluorescent protein (FP) results in the formation of a chromobody. POI can be visualized and traced using this chromobody.

Fig. 2

Application of nanobodies in diagnosis and treatment of diseases.

Fig. 3

Systematic review flow chart of the first literature search according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.