study showing moxidectin and ivermectin exhibited antiviral activity in Vero E6 cells. Authors indicate that no statistically significant effect was seen in Calu-3/PBEC cells, however Figure 3 shows a dose dependent reduction with ivermectin and moxidectin, and the actual values are not provided. Calu-3 is one of many cell lines derived from human lung carcinomas . Calu-3 cells resemble serous gland cells. They do not express 15-lipoxygenase, an enzyme specifically localized to the surface epithelium, but they do express secretory component, secretory leukocyte protease inhibitor, lysozyme, and lactoferrin, all markers of serous gland cells.  note that the absence of systemic inflammation, circulatory factors, and other paracrine systemic influences is a potential limitation of the isolated cell system.
Kumar et al., 3/17/2021, preprint, 14 authors.
In Vitro studies are an important part of preclinical research, however results may be very different in vivo.