Related Experiment Videos
Staphylococcal alpha toxin promotes blood coagulation via attack on human platelets
S Bhakdi1, M Muhly, U Mannhardt
1Institute of Medical Microbiology, Giessen, Federal Republic of Germany.
The Journal of Experimental Medicine
|August 1, 1988
Summary
Staphylococcus aureus alpha toxin forms pores in cell membranes, but human cells show natural resistance due to plasma factors. This limits its role in human staphylococcal infections.
Area of Science:
- Microbiology
- Biochemistry
- Cell Biology
Background:
- Staphylococcus aureus is a significant human pathogen.
- Alpha toxin, a major virulence factor, forms transmembrane pores.
- Its role in human disease is debated due to species-specific resistance.
Purpose of the Study:
- To investigate the mechanism of alpha toxin pore formation.
- To understand the basis of differential susceptibility to alpha toxin.
- To evaluate the relevance of alpha toxin in human staphylococcal infections.
Main Methods:
- Biophysical characterization of alpha toxin pore formation.
- Comparative studies of toxin activity on different cell types (e.g., rabbit vs. human erythrocytes).
- Assessment of alpha toxin neutralization by human plasma components.
Main Results:
- Alpha toxin forms hexameric ring structures that create transmembrane pores.
- Human cells exhibit significantly higher resistance to alpha toxin-induced lysis compared to rabbit cells.
- Human plasma contains factors that neutralize alpha toxin activity in vitro.
Conclusions:
- Alpha toxin pore formation is a two-step process involving monomer binding and oligomerization.
- Natural resistance and plasma-mediated neutralization reduce the effective concentration of alpha toxin, questioning its pathogenicity in humans.
- Further research is needed to clarify the precise role of alpha toxin in human staphylococcal diseases.