Effect of human polymorphonuclear and mononuclear leukocytes on chromosomal and plasmid DNA of Escherichia coli. Role of acid DNase
Phagocytosis and killing by polymorphonuclear and mononuclear leukocytes are important host resistance factors against invading microorganisms. Evidence showing that killing is rapidly followed by degradation of bacterial components is limited. Therefore, we studied the fate of Escherichia coli DNA following phagocytosis of E. coli by polymorphonuclear and mononuclear leukocytes. (/sup 3/H)Thymidine-labeled, unencapsulated E. coli PC2166 and E. coli 048K1 were incubated in serum, washed, and added to leukocytes. Uptake and killing of the bacteria and degradation of DNA were measured. Although phagocytosis and killing by mononuclear leukocytes was less efficient than that by polymorphonuclear leukocytes, only mononuclear leukocytes were able to degrade E. coli PC2166 DNA. Within 2 h, 60% of the radioactivity added to mononuclear leukocytes was released into the supernate, of which 40% was acid soluble. DNA of E. coli 048K1 was not degraded. To further analyze the capacity of mononuclear leukocytes to degrade E. coli DNA, chromosomal and plasmid DNA was isolated from ingested bacteria and subjected to agarose gel-electrophoresis. Only chromosomal DNA was degraded after phagocytosis. Plasmid DNA of E. coli carrying a gene coding for ampicillin resistance remained intact for a 2-h period after ingestion, and was still able to transform recipient E. coli cells after this period. Although we observed no DNA degradation during phagocytosis by polymorphonuclear leukocytes, lysates of both polymorphonuclear and mononuclear leukocytes contained acid-DNase activity with a pH optimum of 4.9. However, the DNase activity of mononuclear leukocytes was 20 times higher than that of polymorphonuclear leukocytes. No difference was observed between DNase activity from polymorphonuclear and mononuclear leukocytes from a chronic granulomatous disease patient with DNase activity from control polymorphonuclear and mononuclear leukocytes.
- Research Organization:
- Department of Clinical Bacteriology, University Hospital, Utrecht, The Netherlands
- OSTI ID:
- 6743302
- Journal Information:
- J. Clin. Invest.; (United States), Journal Name: J. Clin. Invest.; (United States) Vol. 73:5; ISSN JCINA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Molecular cloning and characterization of a Streptococcus sanguis DNase necessary for repair of DNA damage induced by UV light and methyl methanesulfonate
Mechanisms of innate immunity. Cytoplasmic granules of polymorphonuclear neutrophilic granulocytes, antimicrobial action, translocation, role and fate in antimicrobial phagocytosis. Final progress report
Related Subjects
550901* -- Pathology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AZINES
BACTERIA
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CELL CONSTITUENTS
DNA-ASE
ELECTROPHORESIS
ENZYME ACTIVITY
ENZYMES
ESCHERICHIA COLI
ESTERASES
HETEROCYCLIC COMPOUNDS
HYDROLASES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LEUKOCYTES
MATERIALS
MICROORGANISMS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHAGOCYTOSIS
PHOSPHODIESTERASES
PLASMIDS
PYRIMIDINES
RIBOSIDES
THYMIDINE
TRACER TECHNIQUES
TRITIUM COMPOUNDS