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Anthrax lethal toxin paralyzes neutrophil actin-based motility
Russell L During1, Wei Li, Binghua Hao
1Department of Medicine/Infectious Diseases, University of Florida, Gainesville, FL 32610, USA.
The Journal of Infectious Diseases
|August 10, 2005
Summary
Anthrax lethal toxin (LT) paralyzes neutrophils by inhibiting actin assembly, crucial for cell movement and immune response. This study shows LT significantly impairs neutrophil chemotaxis and actin filament formation.
Area of Science:
- Immunology
- Microbiology
- Cell Biology
Background:
- Bacillus anthracis infection leads to high-level bacteremia, indicating innate immune system dysfunction.
- Neutrophil chemotaxis, essential for immune response, relies on actin filament assembly.
Purpose of the Study:
- To investigate the impact of anthrax lethal toxin (LT) on human neutrophil chemotaxis and actin assembly.
Main Methods:
- Human neutrophils were exposed to a sublethal concentration of LT (50 ng/mL) for 2 hours.
- Neutrophil apoptosis, necrosis, morphology, and formylmethionylleucylphenylalanine (FMLP)-stimulated chemotaxis were assessed.
- FMLP-induced actin filament assembly was quantified.
Main Results:
- LT exposure did not induce significant apoptosis or necrosis.
- LT significantly reduced FMLP-stimulated chemokinesis (>60%) and polar morphology.
- LT impaired neutrophil chemotactic responsiveness and reduced FMLP-induced actin filament assembly by over 50%.
Conclusions:
- Two hours of LT exposure markedly impairs human neutrophil actin assembly.
- Reduced actin filament content correlates with profound paralysis of neutrophil chemotaxis.
- LT disrupts critical neutrophil functions necessary for combating bacterial infections.