[refurb]

If the virus is infecting a cell through the ACE2 receptor, wouldn’t upregulating the receptor just increase the risk of infection?

As per the paper, you want to either block the receptor or down regulate it.

[Alex3917]

That definitely could be true, but from what I've read it probably isn't. One of the ways the virus kills people is by destroying their ACE2 receptors, which your lung cells need to function. If you blocked them all, your lung cells would die anyway. So as long as the virus can enter your lung cells, you might as well prevent it from killing them by making extra ACE2 receptors. That's the theory anyway.

There are also many other ways you can block the virus from entering your lungs that don't involve downregulating your ACE2 receptors.