FIGURE 1.

PTx increases invasion and translocation of E. coli K1 RS218. A, pretreatment of HBMEC with PTx (200 ng/ml) for 6 h significantly increases the translocation rate of E. coli HB101 by 3.52 ± 0.13-fold and E. coli K1 RS218 by 6.72 ± 0.55-fold, respectively. B, 6-h PTx pretreatment (200 ng/ml) of HBMEC significantly increases the invasion rate of the pathogenic E. coli K1 RS218 strain by 4.11 ± 0.59-fold compared with untreated HBMEC. No significant changes were observed for the nonpathogenic E. coli HB101 strain. Bars, mean ± S.E. (error bars) of three independent experiments performed in triplicate. **, p < 0.01; ***, p < 0.001 (determined by ANOVA followed by Bonferroni post hoc test).