Figure 4.

Combination of α4–1BB and αCTLA-4 provides tumor protection by increasing the ratios of CD8⁺ T cells to immunosuppressive populations. Mice bearing subcutaneous mEER tumors were either untreated or treated with intranasal HPV peptide vaccine, α4–1BB, or αCTLA-4 individually or in combinations as described in Fig. 1 legend. Tumors were harvested at day 15 and the isolated leukocytes were characterized by flow cytometry after staining for different surface and intracellular markers. The figure shows percentages of CD8⁺T cells (A), frequencies of CD8⁺ T cells as number of cells per tumor area (B), percentages of CD8⁺ T cells expressing GrzB and KLRG1 (C), frequencies of CD8⁺GrzB⁺KLRG1⁺ cells (D), percentages of CD4⁺FoxP3⁺ Tregs (E), frequencies of CD4⁺FoxP3⁺ Tregs (F), CD8⁺ T cells to Treg ratio (G), percentages of CD11b⁺Gr1⁺ MDSCs (H), frequencies of CD11b⁺Gr1⁺ MDSCs (I), and the CD8⁺ T cells to MDSC ratio (J). Data are represented as means ± SEM. Results represent pooled data from multiple experiments (n = 2–11 mice/group). Statistical significance was calculated using one-way ANOVA. *, P < 0.05; **, P < 0.005; ***, P < 0.0005; ****, P < 0.00005.