IL10 and infection: Similar to our findings, anti-PD-L1 treatment increased the number of IL-10-producing Treg cells during Toxoplasma gondii infection, which coincided with the reduction of pathogen-specific effector T cell responses and can be reverted by blocking IL-10 receptor signaling (57), suggesting that a Treg cell-specific PD-1/IL-10 signaling axis is involved in host defense against infections.