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Killing of Proteus mirabilis by polymorphonuclear leukocyte granule proteins: evidence for species specificity by
W M Shafer1, S A Engle, L E Martin
1Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322.
Abstract:
Low-molecular-weight (Mr, ca. 3,800) polypeptides containing human defensins HNP-1 and HNP-2 (T. Ganz, M. S. Selsted, D. Szlarek, S. L. Harwig, K. Daher, D. F. Bainton, and R. I. Lehrer, J. Clin. Invest. 76:1427-1434, 1985) prepared in our laboratory from acid extracts of human polymorphonuclear granulocyte granules and purified human defensins were found to exert potent bactericidal action against Proteus mirabilis. The antimicrobial action of the extracts of human polymorphonuclear leukocytes granules against P. mirabilis appears to be due to the presence of the defensins. Because P. mirabilis resists the antimicrobial action of other granule proteins, we interpret the present results to mean that the various antimicrobial proteins display species specificity in their microbicidal action.
Insights
Human defensins from white blood cell granules show potent bactericidal action against Proteus mirabilis. This suggests antimicrobial proteins have species-specific microbicidal activity.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- Human defensins are low-molecular-weight polypeptides found in polymorphonuclear granulocyte granules.
- These defensins (HNP-1 and HNP-2) are known antimicrobial agents.
Purpose of the Study:
- To investigate the bactericidal activity of human defensins against Proteus mirabilis.
- To determine if defensins are responsible for the antimicrobial action observed in granulocyte granule extracts.
Main Methods:
- Preparation of low-molecular-weight polypeptides from acid extracts of human polymorphonuclear granulocyte granules.
- Purification of human defensins (HNP-1 and HNP-2).
- Testing the bactericidal effect of these preparations against Proteus mirabilis.
Main Results:
- The prepared human defensins exhibited potent bactericidal action against Proteus mirabilis.
- Antimicrobial activity in the granule extracts was attributed to the presence of defensins.
- Proteus mirabilis demonstrated resistance to other granule proteins, highlighting defensins' specific action.
Conclusions:
- Human defensins are key components responsible for the bactericidal activity against Proteus mirabilis.
- The findings suggest that different antimicrobial proteins possess species-specific microbicidal actions.