On the origin of peritoneal resident macrophages. I. DNA synthesis in mouse peritoneal resident macrophages

Abstract

Mouse resident macrophages were isolated from the unstimulated peritoneal cavity at various intervals after one intravenous injection of tritiated thymidine. EM autoradiography showed that 15 min after the injection, peritoneal resident macrophages, with the characteristic localization of the peroxidatic activity in the rough endoplasmic reticulum and the nuclear envelope, had already incorporated tritiated thymidine. In the peripheral blood, monocytes with silver grains over the nuclei were seen from 12 h onwards with a maximum at 48 h. In the peritoneal cavity labelled monocytes appeared at 24 h. The peak for labelled blood monocytes was not followed by a peak for labelled peritoneal resident macrophages. The conclusion is drawn that resident macrophages from the unstimulated peritoneal cavity are able to proliferate locally.