FIGURE 6.

Color contour maps of the out-of-plane component of the three-dimensional traction vector highlighting integrin-dependent traction generation in unconfined two-dimensional (A) and confined 2.5D (B) systems as well as integrin independence upon anti-β₁β₂ blockade (C) and in the absence of matrix ligand on PEG-coated substrates (D). Integrin-dependent traction generation shows a distinct localized out-of-plane traction distribution in the uropod of the cell (A and B) similar to the results shown in Fig. 4. In the absence of integrins, neutrophils generate most of their surface tractions using contact pressure of their nuclear region (C and D). All of the color bars represent tractions in Pa. Positive and negative t₃ traction are defined using the local, positive outward normal vector for each upper and lower gel as illustrated in Fig. 2B. Scale bar, 10 μm.