FIGURE 5.

Effects of the C. jejuni infection on caspase activity. Co-cultures of HT-29/B6-GR/MR and THP-1 cells were infected with C. jejuni with or without apoptosis inhibitor Q-VD-OPh. (A) Caspase-3 cleavage in western blot after C. jejuni infection. Immunoblotting was performed on the cell lysates 22 h after infection. Staurosporine was used for the induction of apoptosis at the concentration of 1 μM as a positive control. Western blot densitometry represented in percent of the mean value in control samples. Western Blot intensity was normalized with β-actin level, n = 6, **p < 0.01. (B) Caspase-3/7 activity measured in a luminescense assay on cell lysates after 22 h of infection. Staurosporine (Ssp., 1 μM) incubated samples were used as positive controls. Data are represented in relative fluorescence units (RFU), n = 6, ***p < 0.001. (C) Apoptosis induction measured by TUNEL staining, showing DNA defragmentation in fluorescence microscopy. DAPI was applied as a nuclear counterstain. (D) Quantitative analysis of apoptotic cells in TUNEL staining (indicated by white arrows). Number of apoptosis positive cell nuclei was estimated in five high power fields per sample, containing approximately 1600 cells each. n = 6, ***p < 0.001, unpaired Student’s t-test with Bonferroni-Holm adjustment for multiple comparisons.