Enhancement of macrophage-mediated tumor cell killing by bacterial outer membrane proteins (porins).


Journal Article

Various microbial products are known to influence the function of mouse peritoneal macrophages. Lipopolysaccharide (LPS) and certain lipid A-associated proteins are known to enhance the tumoricidal effects of macrophages. The purpose of this study was to determine whether porins (outer membrane proteins) of Salmonella typhimurium G30/C21 would influence the activity of macrophages from lipid A-responsive and -unresponsive mice. Porins, extracted by a combined sodium dodecyl sulfate-EDTA method from cell walls, were free of LPS as determined by Limulus amebocyte lysate assay and appeared as a band at approximately 36,000 molecular weight on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In tumor cell killing assays done under LPS-free conditions, the porins in doses of 1 to 10 ng/ml enhanced the tumoricidal effect of macrophages from bacillus Calmette-Guérin-infected C3H/HeN or C3H/HeJ mice. Protein-free LPS enhanced the tumoricidal activity of macrophages from bacillus Calmette-Guérin-infected C3H/HeN but not C3H/HeJ mice. The tumoricidal-enhancing activity of protein-free LPS was blocked by the lipid A-binding antibiotic polymyxin B sulfate, but the effects of porins were not altered by the polymyxin B sulfate. These results suggest that porins, proteins known to alter membrane function, may alter macrophage function by interaction with macrophage membranes.

Full Text

Duke Authors

Cited Authors

  • Weinberg, JB; Ribi, E; Wheat, RW

Published Date

  • October 1, 1983

Published In

Volume / Issue

  • 42 / 1

Start / End Page

  • 219 - 223

PubMed ID

  • 6311745

Pubmed Central ID

  • 6311745

International Standard Serial Number (ISSN)

  • 0019-9567

Digital Object Identifier (DOI)

  • 10.1128/IAI.42.1.219-223.1983


  • eng

Conference Location

  • United States