FIGURE 4.

PGG suppresses the binding of Spike-RBD on ACE2 receptor in HEK293 cells. (A) HEK293 cells were transiently transfected with hACE2-EGFP (green). After 24 h, the cells were incubated with supernatant containing mFc-tagged SARS-CoV-2-RBD with or without PGG (25–100 μM) for 40 min. The cells were subsequently fixed and detected with mouse IgG Fc TRITC antibody (red). All images were captured by confocal microscopy using a Leica SP8 (×40 oil immersion objective lens). (B) Images of Spike-RBD-ACE2 binding intensity were quantified by ImageJ. Data were expressed as mean ± S.D., n = 3; *p < 0.05, one-way ANOVA analysis.