CD8⁺ cells alter CXCR4 signaling events in CD34⁺ cells.

CD34⁺ cells were incubated alone (red) or with CD8⁺ (green) or CD4⁺ (blue) cells. Intracellular signaling events were then measured specifically in CD34⁺ cells in response to SDF-1α stimulation. (A) Calcium flux. (B) Intracellular levels of phosphotyrosine as measured by staining with anti-TyrP FITC. (C) Intracellular levels of phosphorylated FAK as measured by staining with phospho-FAK goat anti-mouse (GAM) PE at the indicated intervals after addition of SDF-1α. Representative results of 3 independent experiments with consistent results are shown.