Immunofluorescence and enzyme cytochemical analysis of arterial terminals in the human spleen.

The simultaneous application of immunofluorescent and enzyme cytochemical methods made it possible to analyze the components of the walls of the arterial branches and arterial capillaries, and particularly the spongy arterial terminals in the red pulp of human spleen. The endothelium was identified by alkaline phosphatase demonstration, the basement membranes (BM) by means of antisera to glomerular BM, the media by using the same antisera, and the adventitia by means by antisera to hyaline cartilage, which are presumed to react particularly with adventitial structures. In the spongy arterial terminals visualized by means of anti-hyaline-cartilage antisera, the endothelium and mostly also BM could be detected, yet the enzyme cytochemical reaction to acid phosphatase and alpha-naphthyl acetate esterase and the immunofluorescent reaction to lysozyme yielded negative reactions. The findings suggest that neither macrophages nor other cells containing the given enzymes in detectable form are accumulated in these structures.