Figure 1.

Basolaterally conditioned media of S. typhimurium–infected epithelia induce IL-8 secretion in virgin epithelia. Model intestinal epithelia were apically exposed to S. typhimurium. The epithelial media was then transferred to untreated model epithelia. IL-8 was assayed in basolateral media 5 hours later. (a) Media was transferred maintaining its polarity of origin (i.e., apical to apical, basolateral to basolateral) 1 hour after addition of bacteria. Live S. typhimurium (added apically for 5 hours) served as a positive control. (b) Basolateral media was transferred at the indicated time after addition of bacteria.