The Src kinase inhibitor, PP2, blocks the cell shape and CD43 polarization of activated primary T lymphocytes.

Purified CD4⁺ splenic T cells were preincubated with 20 μM PP2 in complete medium, then activated with beads coated with anti-CD3 and anti-CD28, fixed, and stained for CD43 as described in “Materials and methods.” (A) Control T cells untreated with PP2 inhibitor and activated at the same time as treated cells. The cells are clearly polarized and CD43 is redistributed away from the cell-bead contact site. (B) Cells treated with the inhibitor and activated. They are characterized by a round shape and lack CD43 redistribution. The results are representative of 2 experiments. The arrows indicate location of the beads. (C) Quantitation of cell shape and CD43 polarization of primary T lymphocytes treated with PP2. The bars represent the cells polarized as a percentage of bead-conjugated cells from 2 experiments. The results for PP2 treated (striped bar) and for control (white bar) T cells are shown. Two slides with 50 to 110 bead-conjugated cells counted on each were evaluated in an experiment. The error bars represent 1 SD. The difference for cell shape polarization was significant at P < .005 and the difference for CD43 polarization was significant atP < .05. Magnification × 1000.