Figure 2.
Schematic of leukocyte microvilli penetrating the EGL. A microvillus on the surface of the leukocyte has a height hMi, and its tip is approximated as a sphere with radius RM. The maximal microvillus length is hmax. We use our measured values of the thickness of the EGL (labeled th) and the modulus of the EGL. As the microvillus is pressed into the EGL, we calculate the compression of the microvillus δM and the penetration depth into the EGL δg as functions of the indenting force to estimate how much force is needed to bring integrin molecules located near the base of the microvillus into bonding range with ligands on the endothelial cell surface. To see this figure in color, go online.