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

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. •The clinical use of classical antibodies raises complex issues.•Nanobodies as the single-chain antibodies are now widely used and tested in the treatment of many diseases.•Many nanobodies have been produced against various viruses.•The nanobodies can be considered as prominent agents to treat COVID-19 infectious disease.