A new monoclonal antibody, TRPM-3, binds specifically to certain rat macrophage populations: immunohistochemical and immunoelectron microscopic analysis.

An anti-macrophage monoclonal antibody designated TRPM-3 was produced using thioglycollate-elicited rat peritoneal macrophages as immunogen. By the immunoperoxidase method, TRPM-3 was found to be specific for certain macrophage populations, such as marginal zone macrophages and marginal metallophils of the spleen, sinus macrophages of the lymph nodes, and omentum macrophages. No epithelial cells, peripheral blood monocytes, granulocytes, or lymphocytes had reacted with TRPM-3. Immunoelectron microscopically, reaction to TRPM-3 was clearly demonstrated on the plasma membrane of splenic marginal zone macrophages, lymphatic sinus macrophages, omentum macrophages, and peritoneal macrophages. Accordingly, TRPM-3 was considered to have recognized the particular membrane antigen expressed by restricted macrophage populations.