Anti-RMA: a murine monoclonal antibody that activates rat macrophages. I. Distribution and characterization of the RMA antigen

Am J Respir Cell Mol Biol. 1990 Feb;2(2):207-15. doi: 10.1165/ajrcmb/2.2.207.

Abstract

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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antibodies, Monoclonal*
  • Antigens / analysis*
  • DNA / biosynthesis
  • Epitopes / analysis
  • Female
  • Immunoenzyme Techniques
  • Interferon-gamma / pharmacology
  • Lipopolysaccharides / pharmacology
  • Macrophage Activation*
  • Macrophages / immunology*
  • Macrophages / metabolism
  • Macrophages / ultrastructure
  • Microscopy, Electron
  • Precipitin Tests
  • Pulmonary Alveoli / cytology
  • Rats
  • Rats, Inbred Lew
  • Tetradecanoylphorbol Acetate / pharmacology
  • Tumor Necrosis Factor-alpha / pharmacology

Substances

  • Antibodies, Monoclonal
  • Antigens
  • Epitopes
  • Lipopolysaccharides
  • Tumor Necrosis Factor-alpha
  • Interferon-gamma
  • DNA
  • Tetradecanoylphorbol Acetate