CloneID: aRBD-5
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 with 0.02% Proclin 300.
Available Custom Conjugation Options: AP, HRP, Fluorescein, APC, PE, Biotin Type A, Biotin Type B, Streptavidin, FluoroProbes 647H, Atto488, APC/Cy7, PE/Cy7
Uniprot Accession No.: P0DTC2
Specificity Statement: The antibody binds the Spike protein of the SARS-CoV-2.
Application Notes (Clone): The VHH and 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 0.674 nM and 1.016 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 16.3 nM and 1.25 nM 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 a hetero-bivalent VHHs, aRBD-2-5, which showed significantly higher RBD binding affinities (KD of 59.2 pM). Similarly, the Fc fusion also showed enhanced binding affinities, with KD values of 12.3 pM. The homo- and hetero-bivalent VHHs exhibited potent neutralizing ability against SARSCoV-2 inoculated onto Vero E6 cells. The 50% neutralization dose was 1.22 ng/ml (0.043 nM) for aRBD-2-5. Finally, the ND50s for aRBD-2-5-Fc was 11.8 ng/ml (0.107 nM) (Ma et al, 2021; PMID:33658349).
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