Figure 4
Live BCG interacts with epithelial cells to induce necrosis, but not apoptosis. (a) Effect of UV treatment on BCG viability. BCG treated for 30 min under UV light (Ultraviolet germicidal irradiation (UVGI)) demonstrated a significant ‘kill’ efficacy of 99% (Two-Way ANOVA in conjunction with Tukey’s Multiple Comparisons Test; ****P ≤ 0.0001). Data presented as cfu/mL Means ± SD; n = 3. (b) No significant increase in caspase 3/7 activity was observed in either cell type when infected with live BCG, compared with untreated (UT) cells over 48 h (Two-Way ANOVA in conjunction with Tukey’s Multiple Comparisons Test; P ≥ 0.05). No effect was detected in cells treated with UVGI BCG. (c) LDH cytotoxicity assay revealed significant increase in BATII cell death only with live BCG (Two-Way ANOVA in conjunction with Tukey’s Multiple Comparisons Test; **P ≤ 0.01), but not BPAEC endothelial cell cultures. (d) Cell viability as indicated by the CellTiter-Glo assay indicates only live BCG has a detrimental effect on BATII cell viability, with no noticeable effect in BPAEC cultures. Viability was not affected in either culture when infected with UVGI BCG. (e) IL8 release both constitutive and in response to BCG is polarised towards the basolateral aspect of the co-culture, showing significant increases at 24 (apical) and 48 h (apical and basolateral) (One-way ANOVA followed by Tukey’s Multiple Comparisons test). (f) TNFα release is also polarised towards the basolateral aspect of the culture, showing significant increases at 24 and 48 h in both apical and basolateral fractions. All data for (e,f) presented as Mean ± SD, n = 3; *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001, ****P ≤ 0.0001.
