The homogeneity and monocytic origin of human peritoneal macrophages evidence by comparison of esterase polymorphism.

The aim of this study was to test the hypothesis of the homogeneity and monocytic origin of the normal unstimulated (resident) peritoneal macrophages in man. The isoelectric focusing pattern of one of the lysosomal marker enzymes, acid esterase (EC 3.1.1.6), was studied in highly purified samples of normal human blood cell fractions. All types of blood cells showed a cell-specific constellation of their enzyme variants as far as blood cells were concerned. Comparisons were made with resident peritoneal macrophages of healthy subjects. Only blood monocytes shared all their isoenzymes with peritoneal macrophages. Two additional bands, not seen in monocytes, occurred, however, in peritoneal macrophages. During exposure of blood monocytes to prolonged glass adherence there was a gradual transition of the monocytic pattern into that of peritoneal macrophages. The results document the homogeneity and monocytic origin of resident peritoneal macrophages in man.