Consistent with the essential role for CTLA-4 in Treg suppression during non-infection conditions in vivo[46], significant reductions in Salmonella recoverable CFUs and accelerated T cell activation were found with CTLA-4 blockade initiated beginning day 5 after Salmonella infection, and the magnitude of these changes paralleled those following DT-induced Treg ablation in F1 Foxp3DTR mice (Figure 8C and D). Here, CTLA4 is linked to infection.