Expression of the rat ED2 antigen by macrophages in splenic erythroblastic islands. Microphotographs from the red pulp areas from the spleens of a juvenile 7-day-old rat (A), or an adult animal 6 days after P berghei infection (B), double-stained with mAb ED2 for rat CD163 (black) and mAb OX26 for rat transferrin receptor–positive erythroblasts (red).