The ultrastructure of eosinophilic granulocytes in the peritoneal cavity of rats following injection of ferritin.

Electron microscopic studies were performed on eosinophilic granulocytes obtained from the peritoneal cavity of rats by peritoneal lavage using 50 ml physiological saline at varying times after intraperitoneal injection of ferritin. Ten minutes after the injection the cytoplasm of the eosinophilic leukocytes showed phago-lysosome-like inclusions containing ferritin. These inclusions were also present one hour after the injections of ferritin. The ferritin phagocytosis results in morphological changes of the eosinophilic granules, but not in degranulation of the eosinophilic cells. In the neutrophilic cells of the peritoneal fluid there were clusters of phago-cytized eosinophilic granules exhibiting signs of degenerative changes. The phagocytosis of eosinophilic granules is interpreted as a link in the disintegration of the eosinophilic leukocytes.