Other research groups also reported that autophagy is essential for Thymus cell/lymphocyte (T-cell) -mediated apoptosis which can be enhanced by AKT/mTOR/Phosphoinositide 3-kinase (PI3K) inhibitors. These studies indicate that autophagy is essential for T-cell mediated apoptosis signaling. Because autophagy is at least partially down-regulated by mTOR, mTOR inhibitors such as sirolimus can be used to pharmacologically induce autophagy. Overall, these findings suggest that activation of mTOR and resultant suppression of autophagy play a critical role in resistance of IDO1 inhibitor.