Figure 5.

SFV-IL-12 + anti-CD137 therapy augments the CD8/Treg ratio and the quality of CD8⁺ T cells. C57BL/6 female mice were flank-inoculated with 5 × 10⁵ B16-OVA cells on day 0 and then received intratumorally saline or 10⁸ viral particles (vp) of SFV-IL-12 on day 7. On days 7 and 10 mice received intraperitoneally 100 µg of rat immunoglobulin G (IgG) or anti-CD137 mAb. On day 11 mice were sacrificed and tumors were harvested, processed, and analyzed by flow cytometry. (a) Graphs show the number of CD8⁺ T cells (left), Tregs (middle), and the ratio between CD8⁺ T and Treg lymphocytes (right). The results are represented as the mean ± standard error of mean (SEM). (b) Representative dot plots of CD25 and FoxP3 expression on CD4⁺ T cells. Numbers indicate the percentages of cells in each quadrant analyzed by fluorescence-activated cell sorting (FACS). Tregs are identified in the upper-right quadrants as CD4⁺CD25⁺Foxp3⁺ cells. (c) Plots showing FACS-assessed size and complexity of intratumoral CD8⁺ T cells. The values on the right upper corner of each panel represent the mean ± SD for FSC or SSC. *P < 0.05; **P < 0.01; α, anti-; SFV-IL-12, Semliki Forest virus encoding interleukin-12.