Figure 6. In situ immunization with CpG plus αOX40/CTLA4 induces depletion of i.t. tumor-specific Tregs.

After a CD4-negative selection, OVA-specific FOXP3-GFP Tregs were FACS sorted from splenocytes of Thy1.2 DO11.10 FOXP3-GFP mice. 2.5 × 10⁵ cells were injected into 5-day-old A20-OVA tumors on the right flank of Thy1.1 BALB/c mice. On day 8, right tumors were treated with i.t. CpG plus low-dose αOX40/CTLA4. On day 4 of therapy, the number of Thy1.2⁺ donor Tregs was counted by FACS in the injected (right) and distant (left) A20-OVA tumors, the right draining lymph nodes (DLN R), the spleen, and the blood of Thy1.1⁺ recipients.