ML339 a selective inhibitor of CXCR6(IC50 = 140 nM) with no response when screened against CXCR5 and CXCR4.
The murine assay was validated using anti-mCXCR16 as an antagonist positive control tested in the presence of an EC80 concentration of mCXCL16 (IC50 = 1.5 nM; % response = 100%). Probe ML339 was shown to be 100-fold less active at the murine CXCR6 receptor using the DiscoveRx β-arrestin cell-based assay format[1].