Anti-RMA: a murine monoclonal antibody that activates rat macrophages. I. Distribution and characterization of the RMA antigen.
Activated macrophages participate in inflammation by eliminating foreign cells, promoting wound healing, and modulating the immune response. A murine monoclonal antibody, designated anti-rat macrophage activator (RMA), was raised against alveolar macrophages (AM) activated with interferon-gamma (IFN-gamma) and phorbol myristate acetate (PMA). The RMA antigen is expressed by resident macrophages but not by other cells. Binding to AM by anti-RMA is not competitively inhibited by the murine monoclonal antibodies MRC OX-41, OX-42, and OX-43. Surface membrane expression of RMA antigens is upregulated by lipopolysaccharide, PMA, and tumor necrosis factor-alpha but not by IFN-gamma. Stimulation of AM with anti-RMA yields distinct ultrastructural alterations, as well as de novo protein and DNA synthesis. Immunoprecipitation of [35S]methionine metabolically labeled AM yields a 120 kD protein by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) that is not altered by chemical reduction. We conclude that the RMA antigen is macrophage specific and that binding of anti-RMA to AM promotes functional activities in a subset of these cells.
Yamin
M
M
Department of Pathology, Massachusetts General Hospital, Boston 02114.
Lazarus
D
D
Schneeberger
E E
EE
McCarthy
K
K
Xia
W J
WJ
Kradin
R
R
D000818:Animals; D000911:Antibodies, Monoclonal; D000941:Antigens / Q000032:analysis*; D004247:DNA / Q000096:biosynthesis; D000939:Epitopes / Q000032:analysis; D005260:Female; D007124:Immunoenzyme Techniques; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism / Q000648:ultrastructure; D008854:Microscopy, Electron; D011233:Precipitin Tests; D011650:Pulmonary Alveoli / Q000166:cytology; D051381:Rats; D011917:Rats, Inbred Lew; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D000941:Antigens; D000939:Epitopes; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D004247:DNA; D013755:Tetradecanoylphorbol Acetate