Fig. 3

Immunization with P. aeruginosa SyBV inhibits the development of bacteria-induced pulmonary inflammation similar to natural OMV. a Study protocol for SyBV immunization for preventing bacteria-induced lung inflammation. b, c The level of TNF-α (b) and IL-6 (c) in BAL fluid was evaluated at 48 h after the last challenge (n = 5). d Representative lung histology images at 48 h after the last challenge (n = 5 with 10 images collected for each, scale bars: 100 μm). eP. aeruginosa-specific IgG titers after the last immunization with OMV or SyBV (n = 5). f The level of P. aeruginosa-specific CD4⁺ T-cell-derived IFN-γ after CD4⁺ T-cells were isolated from immunized spleens (three independent samples). All data are presented as the mean ± s.e.m. ^**P < 0.01, ^***P < 0.001; ns, not significant by two-way ANOVA with Tukey’s post-test versus the sham group