Figure 5.

Secondary capture in arterial vessels induces formation of rolling clusters and rolling strings of leukocytes. (A) Demonstration of rolling clusters in arterial vessels. In A1, the number of leukocytes passing a reference line during 20 consecutive 3-s periods in a WT (top) and an L^−/− (bottom) arteriole are shown. The respective parameters of capture and rolling in the depicted experiments were: Rolling flux, 95 (WT) and 75 (L^−/−); primary capture, 16 (WT) and 22 (L^−/−); and secondary capture, 20 (WT) and 0 (L^−/−). In A2–A6, the buildup of a rolling cluster in a cytokine-stimulated femoral artery is demonstrated. D indicates vessel diameter. P and S indicate primary and secondary capture, respectively. Large arrow indicates direction of flow. Bar, 100 μm. Images were taken at times 0, 0.64, 1.24, 1.52, and 2.52 s. (B) Sequential video frames showing the formation of a rolling string on an atherosclerotic lesion in the right iliac artery of an ApoE⁰/LDLR⁰ mouse in vivo. The orientation of the microscopic images is shown in B1. In B2–B6, the lesion is visible in the bottom left as a bright area. Large arrow indicates direction of flow. Bar, 100 μm. Images were taken at times 0, 0.54, 2.36, 3.20, and 3.96 s.