Inositol 1,4,5-trisphosphate Receptor Interacting Protein-Like 1 or ITPRIPL1 is a transmembrane protein with broad expression in the testis associated with immune evasion. In fact, ITPRIPL1 is a molecule specifically expressed in immune privileged tissues, “hot” tumors without PD-L1 expression, and non-responding tumors to PD-1 blockade therapy. ITPRIPL1 has been shown to impair T cell function in vitro and in vivo through CD3e with experimental evidence supporting a negative correlation between ITPRIPL1 expression level in antigen-presenting cells and T cell cytotoxicity. ITPRIPL1 was a hypermethylated-low expression gene in breast cancer and acted as an independent biomarker for the prognosis of lung adenocarcinoma by using bioinformatics methods. Thus, targeting the ITPRIPL1-CD3e axis, especially in PD-1 - PD-L1 negative patients, is a promising therapeutic strategy to reduce immune evasion.

> 95% as determined by Bis-Tris PAGE; > 95% as determined by HPLC