Fig. 2

TAA-bound OMVs specifically targeted tumors and repressed bladder cancer growth. a Schematic illustration examining how OMV-P 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 with PBS, OMV, or OMV-P on days 6, 10, 16, 20 and 23. b, c Antitumor effect of OMV-P. Tumor size was measured every 3 days. Quantification of the tumor size data are presented in (b, c). Experiments were repeated three times. d) Quantitative analysis of different subsets of CD3⁺CD45⁺ T cells in lymph nodes by flow cytometry (n = 3). Memory CD4⁺ T cells, CD4⁺CD44⁺ T cells. Memory CD8⁺ T cells, CD8⁺CD44⁺ T cells. Activated CD8⁺ T cells, CD8⁺Granzyme-B⁺ T cells. Treg, CD4⁺CD25⁺FoxP3⁺ T cells. e) Quantitative analysis of different subsets of immune cells in PBMCs by flow cytometry (n = 4 or 3). Memory CD4⁺ T cells, memory CD8⁺ T cells, activated CD8⁺ T cells, and Treg were analyzed as described above (n = 4). Macrophages (n = 3), CD45⁺CD11b⁺F4/80⁺ cells. f, h) Cy7-labeled OMV-P were systemically injected into C57/BL6J mice bearing MB49 tumor cells. Whole body distribution of the injected Cy7-OMV-P was observed by an in vivo imaging system on days 0, 1, and 2 after injection. Liver, kidney, spleen, tumor, and lymph node were isolated to measure the accumulation of Cy7 fluorescence in different organs. d, day. g, i Quantification of fluorescence in the tumors (in vivo or ex vivo) (n = 3). Data are shown as mean ± SD. One-way ANOVA with a Tukey multiple comparisons test. NS, no significance; *, p < 0.05; **, p < 0.01; ***, p < 0.001; ****, p < 0.0001