Fig 1: The effect of CXCL12-stimulated CXCR4 on chemokine receptor-mediated migration of human immune cells. (Left) The coexpression of CXCR4 with (A) CXCR1, (B) CXCR3, (C) CXCR5, (D) CXCR6, and (E) CCR2 on human immune cell lines was evaluated by flow cytometry after staining with antibodies specific for the relevant chemokine receptors. Gray peaks indicate isotype controls. (Center) The effect of CXCL12-stimulation of CXCR4 on the chemotactic responses of A CXCR1-coexpressing Jurkat T lymphoblastoid cells to CXCL8, (B) CXCR3-coexpressing HSB2DP T lymphoblastoid cells to CXCL10, (C) CXCR5-coexpressing Raji B lymphoblastoid cells to CXCL13, (D) CXCR6-coexpressing Jurkat T lymphoblastoid cells to CXCL16, and (E) CCR2-coexpressing Molm13 monocytoid cells to CCL2 was assessed by including CXCL12 in the upper chamber (blue) and the other chemokines in the lower chamber (red) in the Boyden two-chamber assay. (Right) The chemotaxis assays were performed with the five cell lines when the placement of the chemokines in the Boyden chambers was reversed. Bar diagrams display mean and SEM (n = 3-4). Statistical analysis by Student’s t test: ***P < 0.001; ****P < 0.0001; ns, not significant.