Fig. 5.

SpxB-mediated H₂O₂ production induces IL-1β release after 6 h of stimulation. Unprimed, LPS-, or TNF-primed human bronchial epithelial cells were infected with D39∆cps and the isogenic mutants at MOI 50 (a, c, d), or stimulated with 150 and 100 μM H₂O₂ in the presence or absence of catalase (b–d). IL-1β release was evaluated at 6 h post infection (a) or stimulation (b). Relative mRNA expression of NLRP3 (c) and pro-IL-1β (d) was quantified in infected and stimulated cells. The data in (a, b) are displayed as box plots. Bars in (c, d) denote mean values ± SD. The level of significance was determined using Kruskal-Wallis test with Dunn's post-test (n ≥ 4; *p < 0.05; **p < 0.01; ***p < 0.001). SD, standard deviation.