Fig. 2 (A) Transendothelial electrical resistance (TEER) of HUVEC monolayers after incubation with the cytotoxic factor for 240 min. The TEER was expressed as a percentage of the zero control. (B) Transcytosis of SEPEC15 and  E. coli  K12 C600 in the absence and in the presence of purified cytotoxic factor. * p  < 0.0001.