Mac-3 immunostained atherosclerotic plaques. (A) Representative Mac-3 immunostainings of severely inflamed plaque. Macrophages are shown in brown color. Adventitia and healthy vessel wall areas were Mac-3 negative. (B) An enlarged area rich in macrophages marked in (A). (C) Non-inflamed plaque with only scanty immunopositivity for Mac-3. L, lumen; P, plaque; W wall.