Fig. 4.

Combined immunofluorescence analysis of placental colocalization of ACE and TMPRSS2.

Confocal fluorescence microscopy of the anemic territory of a TAPS placenta subjected to combined anti-ACE2 (green) and anti-TMPRSS2 (red) immunofluorescence, captured at the same settings. Yellow dots represent regions of colocalization of ACE2 and TMPRSS2, suggestive of membrane fusion. In selected fields, colocalization was confirmed quantitatively using Pearson's correlation coefficient analysis whereby a cutoff of r² > 0.5 was used to indicate positive colocalization.