Figure 7: Detection of in situ intra-tumoral Treg cells (a) and MDSCs (b) in C3 tumor-challenged mice at week five post implantation. Tumor implanted groups of mice were injected with PBS alone (b), or vaccinated using DPX-E7 (a). Frozen tumor tissues were sectioned, fixed and stained for CD4+CD25+ Treg and CD11b+Gr1+ MDSCs, analyzed by confocal microscopy ( magnification). v, blood vessel. Representative sections shown are from 5-6 tumors processed and subjected to blinded analysis in each group.