Fig. 4
Pseudovirus assay of the C5G2 nanobody A Competitive ELISA showed that the C5G2 protein, but not D3, competed with ACE2 to bind RBD with an IC50 of 3.75 nM. As a control, the IC50 of mNb6 for the competition was 4.64 nM. The experiment was performed in triplicate. B Pseudovirus assay of C5G2’s inhibition potency to protect cells from virus infection. The wild-type virus and Alpha, Beta Gamma, Delta and Omicron (BA.1) viruses were tested. mNb6 was used as a positive control. Nanobody D3 binding to NTD of S1 was the negative control. The IC50 values are shown both in ng/ml and nM (nmol/L)