Figure 5:

The effect of brilacidin on viral attachment and the binding of spike RBD or S1 proteins to hACE2. (A) Pseudotyped SARS-CoV-2 viruses were treated with brilacidin at different concentrations for 1h at 37°C. The virus-defensin mixture was added to HeLa-hACE2 cells, and cells were incubated at 4°C for 2h. After washing off unbound viruses, cells were lysed, and cell-associated HIVp24 was determined as described in the Methods. (B) Immobilized spike RBD (484E), RBD (484K), or S1 proteins on the plate were pre-treated with various concentrations of brilacidin for 1h followed by incubation with biotinylated hACE2 proteins at 37°C for 1h. After incubation, plates were washed, and the bound hACE2 proteins were detected by incubation with alkylate phosphatase (AP)-conjugated streptavidin followed by the AP colorimetric assay as described in Methods. Data are mean ± SD of triplicate samples.