Background: Arginase-1 is expressed by liver cells, myeloid-derived suppressor cells (MDSCs), macrophages, and neutrophils.  In mammals, there are three enzymes that metabolise arginine: two arginase isoforms  (ARG1, ARG2) and inducible nitric oxide synthase (iNOS). Arginase-1 catalyzes the breakdown of L-arginine into L-ornithine and urea as the final step in the urea cycle.  L-arginine is a  necessary metabolite for T cell receptor signaling and T cell proliferation. Arginase is induced by inflammation. In cancer, MDSCs within the tumor microenvironment (TME) produce arginase-1 resulting in low levels of available L-arginine within the TME leading to attenuated T cell responsiveness.

Validation: Each lot of conjugated antibody is quality control tested by staining tissue following the MIBI Staining Protocol optimized for the applicable tissue format with subsequent MIBIscope analysis using the appropriate positive and negative tissue field of views. These results are pathologist verified.

Recommended Usage: Human FFPE: 1:100 dilution. For optimal results, the antibody should be titrated for each desired application.

MIBI technology: Learn more about MIBI™ Technology, a multiplex IHC technology with unmatched sensitivity and true subcellular resolution.

References

• Rodríguez, P.C., Ochoa A.C. Arginine regulation by myeloid derived suppressor cells and tolerance in cancer:  mechanisms and therapeutic perspectives. Immunol Rev. 2008; 222:180-91.
• McGaha T.L. et al. Amino acid catabolism: a pivotal regulator of innate and adaptive immunity. Immunol Rev. 2012;  249(1):135-57.

* Conjugate tested on human and mouse FFPE tissue.