The binding of these mAbs to recombinant purified S protein was also determined using indirect ELISA where different concentrations of antibodies were used for binding. Binding to S protein was observed for all four mAbs with 1A9 showing the strongest binding (Figure 3B). Similarly, all four mAbs bound to the full-length S protein of SARS-CoV-2 when tested via IF (Figure 3C). Collectively our data demonstrates the ability of all four mAbs to bind full-length S protein in both its native and denatured forms.