Arginase-1 (E4U1I) Mouse mAb

L-arginine plays a critical role in regulating the immune system (1-3). In inflammation, cancer, and certain other pathological conditions, myeloid cell differentiation is inhibited leading to a heterogeneous population of immature myeloid cells, known as myeloid-derived suppressor cells (MDSCs). MDSCs are recruited to sites of cancer-associated inflammation and express high levels of arginase-1 (4). Arginase-1 catalyzes the final step of the urea cycle converting L-arginine to L-ornithine and urea (5). Thus, MDSCs increase the catabolism of L-arginine resulting in L-arginine depletion in the inflammatory microenvironment of cancer (4,6). The reduced availability of L-arginine suppresses T cell proliferation and function and thus contributes to tumor progression (4,6). Arginase-1 is of great interest to researchers looking for a therapeutic target to inhibit the function of MDSCs in the context of cancer immunotherapy (7). In addition, research studies have demonstrated that arginase-1 distinguishes primary hepatocellular carcinoma (HCC) from metastatic tumors in the liver, indicating its value as a potential biomarker in the diagnosis of HCC (8,9). 1.Albina, J.E. et al. (1989) J Exp Med 169, 1021-9. 2.Mills, C.D. (2001) Crit Rev Immunol 21, 399-425. 3.Rodriguez, P.C. et al. (2004) Cancer Res 64, 5839-49. 4.Gabrilovich, D.I. and Nagaraj, S. (2009) Nat Rev Immunol 9, 162-74. 5.Wu, G. and Morris, S.M. (1998) Biochem J 336 (Pt 1), 1-17. 6.Raber, P. et al. (2012) Immunol Invest 41, 614-34. 7.Wesolowski, R. et al. (2013) J Immunother Cancer 1, 10. 8.Sang, W. et al. (2015) Tumour Biol 36, 3881-6. 9.Geramizadeh, B. and Seirfar, N. (2015) Hepat Mon 15, e30336.