To assess monocyte recruitment, all recipients (anti-JAM-C, WT, or IgG control (not shown) were injected with fluorescent latex beads 48-hrs before sacrifice, which are taken up by circulating monocytes. Beads were identified by FITC+ fluorescence in the transplanted aortic arch sections, with representative sections shown for (A) anti-JAM-C antibody or (B) PBS buffer-control recipients. Beads are indicated with white arrowheads. (C) Beads were counted in aortic arch lesions and quantified by averaging #beads per arch section over at least 4 slides in the transplanted arch, similar to morphometrics. (D) Labeling efficiency of monocytes with the FITC beads was measured by blood draw 24-hrs after beads injection. Blood monocytes were analyzed for labeling efficiency by the percentage of FITC+ monocytes. Data are presented as the mean of three sections ±SEM (N = 6, NS = not significant).