Capture and transmigration of human monocytes on activated HUVECs unaffected by a blocking antibody to JAM-C. (A) A 5-minute bolus of monocytes was flowed over activated HUVECs at a shear stress of 0.05 Pa. Adherent monocytes were then counted and expressed as a mean of triplicate cell counts (± SEM). Decreased monocyte capture was observed with Mac-1–blocking antibody (M1/70; ***P < .005), but not with a blocking antibody to JAM-C. NS indicates not significant. (B) A separate flow assay conducted with a different donor confirmed monocyte capture was unaffected by mAbs to JAM-C. Data represents mean number of cells counted per unit field (± SEM). (C) Adherent monocytes were then cocultured for a further 15 minutes, and the number of monocytes that exhibited migration in the luminal-to-abluminal direction over 20 minutes was recorded and expressed as a mean percentage of total adherent monocytes that remained in field (± SEM). (D) There was increased reverse transmigration with functional blocking mAbs to JAM-C under flow. Cocultured adherent monocytes that underwent primary transmigration that exhibited migration in the abluminal-to-luminal direction over 20 minutes were also recorded. Data presented are the mean percentage of total adherent monocytes per field (± SEM). Increased reverse transmigration was observed for mAbs D33 (*P < .05) and H33 (**P < .01). Percentage of transmigration and reverse transmigration for monocytes treated with M1/70 was not included because of the low number of monocytes captured. Transmigration and reverse-transmigration profiles for flow assays treated under control conditions and with the mAb H33 in panel A were representative of panels B-D (data not shown).