FIG. 1.

Shigella-induced PMN transepithelial migration assay. In this assay, the basolateral surface of inverted T84 monolayers are first colonized by S. flexneri and then washed so that only the cell-associated population remains (cell-adherent plus cell-internalized bacteria). PMN are then placed in the upper (basolateral) reservoir, where they come in contact with the basolateral surface and are subsequently judged for their ability to migrate across these inverted T84 monolayers.