Targeting conserved viral virulence determinants by single domain antibodies to block SARS-CoV2 infectivity

• Published in: bioRxiv 2021-01
• Main Authors: Singh, Sudhakar, Dahiya, Surbhi, Singh, Yuviana J, Beeton, Komal, Jain, Ayush, Sarkar, Roman, Dubey, Abhishek, Syed Azeez Tehseen, Sehrawat, Sharvan
• Format: Article
• Language: English
• Subjects: Antibodies; High temperature; Immunogenicity; Infectivity; Nanobodies; Phage display; Proteins; Proteolysis; Severe acute respiratory syndrome coronavirus 2; Virulence; Viruses
• DOI: 10.1101/2021.01.13.426537

Abstract We selected SARS-CoV2 specific single domain antibodies (sdAbs) from a previously constructed phage display library using synthetic immunogenic peptides of the virus spike (S) protein as bait. The sdAbs targeting the cleavage site (CS) and the receptor binding domain (RBD) in S protein efficiently neutralised the infectivity of a pseudovirus expressing SARS-CoV2 S protein. Anti-CS sdAb blocked the virus infectivity by inhibiting proteolytic processing of SARS-CoV2 S protein. Both the sdAbs retained characteristic structure within the pH range of 2 to 12 and remained stable upto 65°C. Furthermore, structural disruptions induced by a high temperature in both the sdAbs were largely reversed upon their gradual cooling and the resulting products neutralised the reporter virus. Our results therefore suggest that targeting CS in addition to the RBD of S protein by sdAbs could serve as a viable option to reduce SARS-CoV2 infectivity and that proteolytic processing of the viral S protein is critical for infection. Competing Interest Statement The authors have declared no competing interest. Footnotes * Conflict of financial interest The authors declare no conflict of financial interest. The study was supported by intramural funding from IISER Mohali and DBT (BT/PR20283/BBE/117/2016) to SS.