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 arginase-1 antibody is quality control tested by MIBIscope™ analysis of stained tissue microarray using the appropriate positive and negative tissue field of views and are pathologist verified.

Recommended Usage: 1 uL of Arginase-1 antibody per 100 uL staining volume using the MIBI™ Staining Protocol.
For optimal results, antibody should be titrated for each desired application.  Suggested starting range is 1:100.

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 tissue.