Figure 3.
HL-60 cells migrate upstream on ICAM-1 and downstream on VCAM-1 once Mac-1 is blocked: cell traces of HL-60 cells 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 downstream migration (with flow), and red traces indicate upstream migration (against flow). The direction of flow is from left to right in these traces and the traces have units of microns. The direction of HL-60 cell 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). The percentage of migrating cells traveling upstream under isotype, anti-αL-integrin, or anti-αM-integrin blocking at 100 and 800 s−1 shear rate on (C) ICAM-1 or (F) VCAM-1 is shown. HL-60 cells migrate downstream on ICAM-1 and VCAM-1 under isotype conditions, whereas blocking the αM-integrin promotes upstream migration on ICAM-1 but not VCAM-1. Blocking the αL-integrin of removes all upstream migration in ICAM-1 and does not affect VCAM-1 migration. n = 4–5 independent experiments of at least 60 cells analyzed per experiment for each CAM. ∗p < 0.05 with respect to isotype conditions.