Fig. 4

Correlation between expression of ACE2 on target cells and cell capturing ability. Endogenous expression of ACE2 in different cell lines determined by A Western blotting and B qPCR. C The cell capture ability of immobilized S1 to different cell lines. Captured cells were counted manually under the optical microscope; D correlation between ACE2 RNA level and S1 captured cell number fit a linear relationship with R² = 0.82