CloneID: aRBD-7
Antigen Long Description: The original antibody was generated by immunizing two alpacas with highly purified recombinant SARS-CoV-2 RBD, and developing a VHH library. The antibody was isolated by panning against SARS-CoV-2 RBD.
Buffer Composition: PBS only.
Uniprot Accession No.: P0DTC2
Specificity Statement: The antibody binds the Spike protein of the SARS-CoV-2.
Application Notes (Clone): The VHH with IgG1 Fc formats demonstrated strong binding to both RBD and the entire ectodomain (S1+S2) of SARS-CoV-2 spike in ELISA, with a low nanomolar 50% effective concentration (EC50 respectively 0.522 nM and 0.748 nM). The binding affinity of the VHH format and VHH-Fc formats to RBD were also measured using surface plasmon resonance, with KD values of 3.31 nM and 72 pM respectively. Both VHH and Fc fusion formats could block RBD-ACE2 interaction in a dose-dependent manner, as characterized by competitive ELISA. Furthermore, the fusion of two VHHs with nonoverlapping epitopes resulted in the hetero-bivalent VHHs, aRBD-2-7, which showed significantly higher RBD binding affinities (KD of 0.25 nM). Similarly, their Fc fusions also showed enhanced binding affinities, with a KD value of 0.22 nM. The homo- and hetero-bivalent VHHs exhibited potent neutralizing ability against SARSCoV-2 inoculated onto Vero E6 cells. The 50% neutralization dose was 3.18 ng/ml (0.111 nM), for aRBD-2-7. Finally, the ND50s for aRBD-2-7-Fc was 6.76 ng/ml (0.0606 nM) (Ma et al, 2021; PMID:33658349).
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