Figure 4.
Primary PMNs display similar migration profiles to HL-60 cells on ICAM-1 and VCAM-1: cell traces of neutrophils from whole blood on (A) ICAM-1 and (D) VCAM-1 under isotype (first column), with anti-αM-integrin blocking (second column), or with anti-αL-integrin blocking (third column) at 800 s−1 shear rate at a concentration of 2.5 μg/mL. The traces depicted are the cumulative tracks of two independent experiments and have units of microns. Blue traces indicate cells that traveled downstream (with flow), and red traces indicate cells that traveled upstream (against flow). The direction of flow is from left to right in these traces and has units of microns. The direction of PMN migration under shear flow as expressed by the MI under isotype, anti-αM-integrin, or anti-αL-integrin blocking at 100 and 800 s−1 shear rate on (B) ICAM-1 and (E) VCAM-1 is shown. A negative MI indicates migration against the flow (upstream), whereas a positive MI indicates migration with the flow (downstream). Percentage of migrating cells traveling upstream under isotype or anti-αL-integrin blocking at 100 and 800 s−1 shear rate on (C) ICAM-1 or (F) VCAM-1 is shown. PMNs behave exactly like HL-60 cells by migrating downstream on ICAM-1 and VCAM-1 under isotype conditions, whereas blocking the αM-integrin promotes upstream migration on ICAM-1 but not on VCAM-1. Blocking the αL-integrin of removes all upstream migration on ICAM-1 and does not affect VCAM-1 migration. n = 4–5 independent experiments of at least 50 cells analyzed per experiment for each CAM. ∗p < 0.05 with respect to isotype conditions.