TMPRSS2 and infection: However, recent evidence suggests that this might not be the case, and CQ and HCQ might not efficiently block the plasma membrane pathway of cell invasion: while CQ and HCQ blocked infection in Vero E6 cell line (a kidney epithelial cell line that expresses ACE2 but not TMPRSS2; IC50 of CQ: 6.5 μM; IC50 of HCQ: 13.3 μM), these drugs did not block infection in Vero E6 cells recombinantly expressing TMPRSS2 (Hoffmann et al., 2020b).