Direct activation of murine peritoneal macrophages for nitric oxide production and tumor cell killing by interferon-gamma

J Interferon Cytokine Res. 1995 May;15(5):387-94. doi: 10.1089/jir.1995.15.387.

Abstract

Interferon-gamma (IFN-gamma) is known to prime macrophages for tumor cell lysis and nitric oxide (NO) production as measured by enhanced sensitivity to lipopolysaccharide (LPS). In the present study, the ability of IFN-gamma to directly activate peritoneal macrophages from C57BL/6 and Balb/c mice for tumor cytotoxicity and NO production was evaluated. Macrophage-mediated tumor cell killing was measured by an 18 h 51Cr release assay using P815 mastocytoma cells as targets. Concurrent NO production was measured as nitrite in the supernatants of macrophage cultures. Incubation of macrophages with IFN-gamma resulted in activation of macrophages for tumor cell lysis. IFN-gamma alone also activated macrophages for NO production under identical conditions. Addition of LPS along with IFN-gamma resulted in synergism in the activation of macrophages for both cytolysis and NO production. LPS contamination of the IFN-gamma preparation was absent as evidenced by the following criteria: (1) the IFN-gamma preparation as well as the reagents used were shown to be free of LPS contamination based on LAL endotoxin tests (sensitivity 25 pg/ml), (2) the ability of IFN-gamma to activated macrophages was not abrogated by prior treatment of the cytokine with polymyxin B, whereas the effect of LPS was inhibited (70-100%) under similar conditions, (3) pretreatment of the IFN-gamma preparation with a specific endotoxin neutralizing protein did not abrogate the ability of IFN-gamma to induce macrophage activation, and (4) heat treatment of solutions containing IFN-gamma alone or IFN-gamma+LPS abolished only the effect of IFN-gamma, not that of LPS.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Caseins / pharmacology
  • Cytotoxicity Tests, Immunologic
  • Dose-Response Relationship, Immunologic
  • Female
  • Interferon-gamma / pharmacology*
  • Lipopolysaccharides / pharmacology
  • Macrophage Activation / drug effects
  • Macrophage Activation / immunology*
  • Macrophages, Peritoneal / drug effects
  • Macrophages, Peritoneal / immunology*
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Nitric Oxide / biosynthesis*
  • Peptide Fragments / pharmacology
  • Peptones / pharmacology
  • Polymyxin B / pharmacology
  • Recombinant Proteins
  • Temperature
  • Tumor Cells, Cultured

Substances

  • Caseins
  • Lipopolysaccharides
  • Peptide Fragments
  • Peptones
  • Recombinant Proteins
  • proteose-peptone
  • Nitric Oxide
  • Interferon-gamma
  • Polymyxin B