Competition by CXCL11 isoforms for radioactive ligand binding to lymphocytes or CXCR3- or CXCR7-transfected CHO cells. Increasing concentrations of unlabeled synthetic CXCL11(1-73) (■), CXCL11(3-73) (▴), CXCL11(5-73) (♦), CXCL11(7-73) (○), or recombinant CXCL12 (□) were added together with ¹²⁵I-CXCL11 to CHO-CXCR3 cells (A), lymphocytes (B), or CHO-CXCR7 cells (C) or were incubated with CHO-CXCR7 cells in the presence of ¹²⁵I-CXCL12 (D). Results represent the remaining mean (± SEM) percentage specific ¹²⁵I-CXCL11 or ¹²⁵I-CXCL12 binding for 3 to 7 independent experiments.