IL-7 mediates the up-regulation of CXCR4.

(A) CD45RA⁺CD45RO⁻ cells were stimulated with IL-2 or IL-7 or left untreated. A portion of the cells were analyzed for expression of CXCR4 on total lymphocytes (panel Ai), CD4⁺ naive T cells (pane Aii), and CD8⁺ naive T cells (panel Aiii). Flow cytometric analysis was performed by means of quantibright beads to calculate the number of molecules per cell, which are shown on the y-axis. Data represent median values from at least 6 donors (panel A). *Significant P values (P < .001) significant of IL-7 cultures over untreated or IL-2–stimulated cultures as measured by the Kruskal Wallis test. (B) A flow cytometric representation of the data from panel A. Top panel corresponds to CXCR4 expression while bottom panel corresponds to CCR5 expression of untreated, IL-7–treated, or IL-2–treated naive T cells.