Sulf-2 effects on pre- and post-binding assays for chemokines. (A) Binding of CXCL12 (SDF-1), CCL21 (SLC) and CXCL8 (IL8) to immobilized heparin-BSA as a function of ligand concentration with or without Sulf-2 treatment of heparin-BSA. Δ denotes binding of chemokines to untreated heparin-BSA and ● denotes binding of chemokines to rHSulf-2 treated heparin-BSA in pre-binding assay. (B) "Pre-binding effect" (left panel) and "post-binding" effect (right panel) of rHSulf-2 (●) or rΔCCHSulf-2 (○) on ligand binding (CXCL12) to heparin-BSA as a function of enzyme concentration. Values represent the means ± S.D. of triplicate determinations in the binding assays for CXCL8 and CXCL12. Statistical analysis was carried out using Student's t test. **, p < 0.01; ***, p < 0.001. The other data are representative of two independent trials.