STAG2 and influenza: Due to concerns over the effect of cell tropism on infection dynamics, most influenza infection assays are now conducted in Madin-Darby canine kidney (MDCK) cells which have been transfected to express more SA2,6 Gal receptors (called SIATI cells), rather than in regular MDCKs which predominantly express SA2,3 Gal receptors [24].