Predominant localization of aortic DCs in the aortic valve and sinus. Aortic segments from aortic sinus to diaphragm were opened longitudinally to make aortic sheets. The distribution of aortic DCs was analyzed using confocal microscopy. (A) EYFP⁺ DCs in the intima of the aortic arch (top left) and openings of arterial branches (top right). Adventitial EYFP⁺ DCs were scattered throughout the aorta including aortic arch (bottom left) and descending aorta (bottom right) (B) Diagram of aortic sinus. Red indicates DC-abundant areas. (C) EYFP⁺ DCs in aortic valve (left) and sinus (right). (D) Flow cytometric analysis of EYFP⁺ cells. The mean and SD of three experiments are shown below, with the aortic cell suspension in each experiment being from at least three mice. (E) The presence of DCs in normal cardiac valves including left (left panel) and right (right panel) atrioventricular valves. The cardiac valves were isolated using microscissors under guidance of a dissecting microscope. The valvular sheets were mounted on glass slides and observed by confocal microscopy. Each figure is representative of at least three experiments. Bars, 40 µm.