Figure 4.

Bacteria release a PIF with the same properties as that isolated from bacterial-epithelial interactions. An overnight culture of S. typhimurium (S.t.) was pelleted, washed two times by centrifugation, and resuspended in HBSS (10¹⁰ CFU/ml). One hour later, bacterial supernatant was isolated and basolaterally applied to model epithelia where its ability to induce IL-8 secretion was measured.(a) Supernatant was applied over a range of concentrations. (b) Bacterial supernatant was subjected to indicated treatments (as described in Figure 2) before being applied to epithelia.