Fig. 4.

IL-8 production and TEER in inverted polarized T-84 cells infected with S. dysenteriae 1 derivatives. T-84 cells were grown on inverted transwells, and bacteria were applied to the basolateral surface. IL-8 secretion was measured in basolateral supernatants after 24 hours of incubation. TEER was measured prior to infection and at 24 h postinfection and expressed as a percentage of the initial TEER. Bars: BL, blank; A, WT 1617; B, CVD 1254; C, CVD 1255; D, CVD 1256; E, CVD 1257; F, CVD 1255(pOmpC-StxB); G, CVD 1255(pTrc-StxB). The TEER values for strains 1617 and CVD 1254 were significantly less than all other strains and are indicated with an asterisk (P < 0.01, using an unpaired Student's t test).