Table 1. T cell anergy versus T cell exhaustion.

Unresponsive state	Differentiation state affected	Driving forces	General characteristics of the unresponsive state
T cell anergy	Naïve/Effector	Impaired antigen presentation	Impaired activation and proliferation
		Reduced costimulation	Defective differentiation and effector function
		Expression of immunomodulatory molecules (IDO, CD73, CD39)	Apoptosis
		Regulatory cytokines (IL-10, TGF-β)
T cell exhaustion	Effector	Antigen persistence, chronic activation	Progressive impairment of effector function
		Regulatory cytokines (IL-10, TGF-β)	Expression of inhibitory receptors (PD-1, TIM-3, LAG-3)
		Suboptimal priming (while in the naïve state)	Decreased expression of common γ chain cytokine receptors
			Apoptosis