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Fusobacterium necrophorumLeukotoxin Induces Activation and Apoptosis of Bovine Leukocytes
- Source :
- Infection and Immunity. 70:4609-4620
- Publication Year :
- 2002
- Publisher :
- American Society for Microbiology, 2002.
-
Abstract
- Fusobacterium necrophorum, a gram-negative, rod-shaped, anaerobic bacterium, is a primary or secondary etiological agent in a variety of necrotic, purulent infections in humans and animals. Its major virulence factor is leukotoxin, a high-molecular-weight secreted protein, primarily toxic to ruminant leukocytes. In this study, bovine peripheral blood leukocytes were exposed to various concentrations of immunoaffinity-purified leukotoxin and the cytotoxicity was analyzed by flow cytometry and scanning and transmission electron microscopy. At very low toxin concentrations, polymorphonuclear leukocytes (PMNs) showed activation, as indicated by translocation of primary and secondary granules to the periphery of the cytoplasm. Furthermore, these cells showed changes characteristic of apoptosis, including decreased cell size, organelle condensation, cytoplasmic membrane blebbing (zeiosis), and chromatin condensation and margination, and decrease in cellular DNA content. At moderately high concentrations of leukotoxin, bovine mononuclear cells were also induced to undergo programmed cell death. At very high concentrations, leukotoxin caused necrotic cell death of bovine peripheral leukocytes. The ability ofF. necrophorumleukotoxin to modulate the host immune system by its toxicity, including cellular activation of PMNs and apoptosis-mediated killing of phagocytes and immune effector cells, represents a potentially important mechanism of its pathogenesis.
- Subjects :
- Programmed cell death
Neutrophils
Phagocytosis
Bacterial Toxins
Immunology
ved/biology.organism_classification_rank.species
Exotoxins
Apoptosis
Biology
Microbiology
Peripheral blood mononuclear cell
Fluorescence
Immunophenotyping
Flow cytometry
Immune system
Fusobacterium necrophorum
Leukocytes
medicine
Animals
Hydro-Lyases
Respiratory Burst
medicine.diagnostic_test
Cytotoxins
ved/biology
Flow Cytometry
Molecular Pathogenesis
Respiratory burst
Microscopy, Electron
Infectious Diseases
Microscopy, Electron, Scanning
Cattle
Parasitology
Subjects
Details
- ISSN :
- 10985522 and 00199567
- Volume :
- 70
- Database :
- OpenAIRE
- Journal :
- Infection and Immunity
- Accession number :
- edsair.doi.dedup.....1d2ef450b8dc405cfe88295bc7d46404