HETEROGENEITY OF MACROPHAGE POPULATIONS: ANTIBODIES DETECTING VARIOUS POPULATIONS OF MACROPHAGES

Two groups of antibodies against mouse resident alveolar and peritoneal macrophages have been raised individually in rabbits by immunization with whole cell suspensions of lavaged alveolar and peritoneal macrophages. The whole antisera reacted positively with neutrophils and lymphocytes. However, upon extensive absorptions with these cells the activity became restricted to macrophages. The immunoglobulins were purified up to 8 fold by repeated precipitations with saturated ammonium sulphate. The antibodies were labeled with fluorescein isothiocyanate and further used. The specificity of antibodies was confirmed by direct and indirect immunofluorescence and complement-dependent cytotoxicity. In the cytolysis of target cells in the presence of complement, the antibodies could lyse more than 80% of cells at dilutions as low as 1:512.