Ki-M2R is an antibody that recognizes typical tissue macrophages and specifically discriminates between monocytes (Ki-M2R-) and macrophages(Ki-M2R+). It stains all resident macrophages including those of bone marrow, lymphatic sinuses, lymphoid follicles, splenic red pulp, and Kupffer cells in the liver. Langerhans cells, interdigitating reticulum cells, and dendritic reticulum cells of lymphoid follicles are not stained. Ki-M2R is a reliable tool for indicating macrophage differentiation in vivo and in vitro. Application: IHC (f, p)