CMP-5 hydrochloride is a potent, specific, and selective PRMT5 inhibitor, while displays no activity against PRMT1, PRMT4, and PRMT7 enzymes. CMP-5 hydrochloride selectively blocks S2Me-H4R3 by inhibiting PRMT5 methyltransferase activity on histone preparations. CMP-5 hydrochloride prevents EBV-driven B-lymphocyte transformation but leaving normal B cells unaffected. IC50 & Target: IC50: 3.7 μM (mTh1 cells), 9.2 μM (mTh2 cells) 26.9 μM (hTh1 cells), 36.1 μM (hTh2 cells)In Vitro: CMP-5 (0-100 μM; 24-72 hours) is selectively toxic to lymphoma cells, but shows a limited toxicity to normal resting B lymphocytes even after prolonged incubation. CMP-5 (40 μM; 24 hours) decreases p-BTK and pY(416)SRC expression in 60A cells when it compares to the DMSO-treated group. CMP-5 (0-40 μM; 24 hours) preferentially suppresses the proliferation of human Th1 cells over Th2 cells (43 versus 9% inhibition, respectively). The sensitivity of Th1 cells over Th2 cells to PRMT5 inhibition is different, the IC50 values are 26.9 μM and 31.6 μM in human Th1 cells and Th2 cells, respectively. CMP-5 (25 μM; 24 hours) alone inhibits mouse Th1 cell proliferation by 91%, when added different doses IL-2, IL-2 enhances proliferation and reaches a peak at 5 ng/ml.