Neutrophil-epithelial interactions were modelled using polarized T84 cells and ligands were identified through observations of beta2-integrin dependence in patients with chronic granulomatious disease. Interactions between neutrophils and the apical membrane of crypt cells were analysed using HPLC and an in vitro model with T84 monolayers colonized by Salmonella typhimurium was used to assess neutrophil movement across the epithelium. The decline in transepithelial resistance following movement of neutrophils across the epithelial monolayer may have been due to an interaction between neutrophils and ligand ICAM-1 in which the neutrophils move along the paracellular pathway of epithelial cells. Cell surface polarity may influence these neutrophil-epithelial interactions which influence Cl secretion. These studies revealed that only strains produced in vivo were able to induce neutrophil transmigration in the in vitro model and may be indicative of new progressive therapies for inflammatory bowel disease.