Effect of persistent CXCR4 expression on lymphocyte actin polymerization. PBMCs were either untreated or pretreated with SDF-1 (200 ng/mL), SDF-1 plus fucoidan (100 μg/mL), or SDF-1 plus sulfatide (100 μg/mL) for 1 hour at 37°C. Then all cells were washed and restimulated with SDF-1 (200 ng/mL) for 1 minute. Actin polymerization was measured by NBD-phallacidin staining and flow cytometry. Means ± SEM of the fluorescence intensity from 3 experiments are presented. *P < .05 compared with SDF-1 pretreated group.