Table 1.

Pathways assessed to evaluate the mechanistic basis for the T cell suppressive activity of liver Tgfb1^−/− MDSC.

Target Enzyme or Molecule	Inhibitor	Concentration	Effect on MDSC activity
Nitric oxide synthase (NOS) -1, -2, -3	L-NG-monomethyl Arginine citrate (L-NMMA)	5.0 mM	Blocks
NOS-2	N6- (1-iminoethyl)-L-lysine (L-NIL)	0.5 mM	Blocks
Arginase	N-hydroxy-nor-Arginine (nor-NOHA)	1.0 mM	No effect
Indoleamine 2,3-dioxygenase (IDO)	1-methyl-tryptophan (1-MT)	0.2 mM	No effect
Reactive oxygen species (ROS)	Catalase	1000 U/ml	No effect
	Superoxide Dismutase (SOD)	200 U/ml	No effect
PD-L1/PD-1	Blocking Anti-PD-L1 mAb	10 μg/ml	No effect
	Blocking Anti-PD-1 mAb	10 μg/ml	No effect
TGF-β	Blocking Anti-TGF-β-1, -2, -3 mAb	10 μg/ml	No effect
IL-10/IL-10R	Blocking Anti-IL-10 mAb	20 μg/ml	No effect
	Blocking Anti-IL-10R mAb	20 μg/ml	No effect