FIG. 4.

Vaccinia virus produced by airway epithelia preferentially infects epithelia from the basolateral surface. Differentiated epithelia were infected basolaterally with vaccinia virus (vp37-eGFP). Three days later, ASL was collected and used to infect naïve epithelia from the apical (A) or basolateral (B) surface. Three days later, cultures were stained with phalloidin-Alexa (red) to stain actin and ToPro3 to stain nuclei (blue) and analyzed for GFP expression (green).