In addition, endotoxins and the pro-inflammatory cytokines, IL-1β and TNFα, all enhanced soluble catalytic ectodomain ACE2 shedding from the airway epithelia, suggesting that the shedding of ACE2 may represent a mechanism by which viral entry and infection may be controlled, such as with SARS-COV-1 and SARS-COV-2. Here, ACE2 is linked to infection.