Fig. 4

OMV co-delivery of both TAAs and PD-L1 antibody significantly inhibited tumor growth. a Schematic illustration examining how OMV-PP inhibits bladder cancer growth. C57BL/6 mice were s.c. injected with MB49 cells in the right flank on day 0 and s.c. immunized on day 3, 7, 12, and 16 for four total vaccinations. b, c Antitumor effect of OMV-PP. Tumor size was measured every 3 days. d Quantitative analysis of different subsets of CD3⁺CD45⁺ T cells in lymph nodes by flow cytometry (n = 3). e) Quantitative analysis of different subsets of immune cells in PBMCs by flow cytometry (n = 3 or 5). f, g Quantitative analysis of ELISPOT assay for IFNγ secretion to detect immune cell activation of splenocytes (f) and TILs (g) against selected epitopes. 1, PBS. 2, SpC-OMVs. 3, SpT-peptides + anti-PD-L1. 4, SpC-OMVs + SpT-peptides + anti-PD-L1. Data are shown as mean ± SD. One-way ANOVA with a Tukey multiple comparisons test or unpaired two-tailed Student’s t-test. NS, no significance; *, p < 0.05; **, p < 0.01; ***, p < 0.001; ****, p < 0.0001