Figure 4.
iTreg in the TME are highly interactive and engage a variety of immune and non-immune cells. The immune checkpoint inhibitory receptors, CTL-4, PD-1, LAG-3, TIM-3 and TIGIT, are upregulated on the iTreg surface in the TME. The ligands for these receptors are present on a variety of tissue and immune cells so that Treg have an ample opportunity to interact with these various cells. It is possible that these receptors on iTreg control contextual responses of Treg to environmental signals. Engagements of Treg in immune and non-immune activities may be regulated by these receptors.