Improved chimaeric mouse model confirms that resident peritoneal macrophages are derived solely from bone marrow precursors.

The origin of resident peritoneal macrophages was studied in radiation mouse chimaeras with and without reconstitution of the peritoneum with viable isogeneic peritoneal cells. The selection of host and donor strains were such that the isoenzymes of glucose-6-phosphate isomerase could be used to distinguish host from donor bone marrow derived cells. It was found that the resident peritoneal macrophages were completely replaced by bone marrow donor derived cells within 5-6 weeks. There was little difference between the results from mice which had been additionally reconstituted with peritoneal cells and those which were not.