ANPEP and infection: While we observed a fourfold decrease in GD3 on HCT-8 cells following OC43 infection, as well as a 1.7-fold decrease in CD13 expression following 229E infection, we were surprised to observe a significant increase in ACE2 receptor expression and MFI following NL63 infection of LLC-MK2 cells (2.3-fold) but also following OC43 infection (1.8-fold).