Polarized distribution of CD43 and CCR2 on migrating T lymphoblasts. (i) T lymphoblasts adhered to FN80 were stimulated with the TP1/36 anti-CD43 MoAb for 30 minutes at 37°C and then fixed as described under the Materials and Methods. In (A), cells were double-stained with anti-CD43 (orange) and biotinylated-anti-CCR2 chemotactic receptor MoAb (green), and both fluorescences were photographed on the same frame by double exposure. In (B) and (C), cells were stained for CCR2 and CD45 (FITC-conjugated anti-CD45), respectively. Arrows point to the cellular uropods, whereas arrowheads point to the leading edge. Bar = 10 μm. (ii) T lymphoblasts were allowed to adhere to FN80-coated coverslips and then were stimulated with the TP1/36 anti-CD43, HP2/9 anti-CD44, or D3/9 anti-CD45 MoAb. Cells were then stained for CCR2 and the percentage of cells on which the chemokine receptor was redistributed calculated by random choice of 10 fields for each condition and direct cell counting (400 to 500). The arithmetic mean ± SD of three independent experiments is shown.