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M protein mediates streptococcal adhesion to HEp-2 cells
1Department of Microbiology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo 14214-3005.
Infection and Immunity
|February 1, 1994
Summary
Streptococcus pyogenes adhesion to human cells is mediated by M protein. This bacterial adhesin directly binds to specific human epithelial cell membrane components, facilitating infection.
Area of Science:
- Microbiology
- Cell Biology
- Immunology
Background:
- Streptococcus pyogenes is a pathogen that adheres to human epithelial cells.
- Identifying bacterial adhesins is crucial for understanding infection mechanisms.
Purpose of the Study:
- To identify the specific Streptococcus pyogenes adhesins responsible for binding to human epithelial cells.
- To elucidate the interaction between bacterial components and host cell surface receptors.
Main Methods:
- Extraction of S. pyogenes M6 cell wall components.
- Incubation of HEp-2 cells with bacterial extracts and analysis via Western blot.
- Use of pepsin-cleaved M protein fragments and labeled lipoteichoic acid.
- Comparison of adhesion between M+ and M- S. pyogenes strains.
Main Results:
- M protein (62 kDa) was identified as the sole S. pyogenes component binding to HEp-2 cells.
- M protein binds to trypsin-sensitive HEp-2 cell components (97 and 205 kDa).
- Lipoteichoic acid did not mediate M protein binding; M-deficient strains showed significantly reduced adhesion.
Conclusions:
- M protein directly binds to specific human epithelial cell membrane components.
- M protein is a key mediator of Streptococcus pyogenes adhesion to host cells.