Cell surface distribution of plasma membrane markers in polarized CD34⁺ cells. (A-H) CD34⁺ cells isolated from umbilical cord blood and cultured for 2 days in serum-containing medium supplemented with early acting cytokines were subjected to double labeling using AC133 antibody (anti-CD133) and an antibody directed against another cell surface antigen, as indicated, and analyzed by double immunofluorescence. The CD133 immunofluorescence (red) is shown in the second column, the immunofluorescence of various cell surface antigens (green) in the third column, and the corresponding differential interference contrast image as well as the merge are shown in the first and the fourth column, respectively. Note that the chemokine receptor CXCR4 (G) and the ganglioside GM3 (H) are concentrated in the leading edge of the front pole, whereas CD43 (A), CD44 (B), ICAM3/CD50 (C), and ICAM1/CD54 (D) are enriched in the uropod of the polarized cells and colocalized with CD133. All panels are shown at the same magnification.