Effects of Rac 1 and myosin II inhibitors on the migration of Jurkat T and primary CD4⁺ T cells in microchannels. (A and D) Jurkat T cells were treated with NSC23766 (NSC), blebbistatin (Bleb), or vehicle control (Ctrl). (B and E) Jurkat T cells were treated with the α4/paxillin-binding inhibitor, 6B345TTQ, or vehicle control or treated with 6B345TTQ (6BQ) plus NSC23766 or vehicle control. (C and F) Primary WT-CD4⁺ or Y991A-CD4⁺ T cells were treated with vehicle control or NSC23766. Cells were either induced to migrate through channels of different widths (A–C) or plated on a 2D surface (D and E). All surfaces were coated with VCAM-1. Cell migration velocities (A–C) and mean spreading areas (D and E) were quantified. Data represent means ± SEM of >60 cells. *, P < 0.005 relative to control (A and B) or WT-CD4⁺ T cells (C). ^§, P < 0.005 compared with the absence of NSC23766.