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Prokaryotic peptides that block leukocyte adherence to selectins
E Rozdzinski1, W N Burnette, T Jones
1Laboratory of Molecular Infectious Diseases, Rockefeller University, New York, New York 10021.
The Journal of Experimental Medicine
|September 1, 1993
Summary
Pertussis toxin subunits mimic selectins, crucial for immune cell movement. This mimicry impacts how bacteria adhere to cells and influences disease development.
Area of Science:
- Microbiology
- Immunology
- Cell Biology
Background:
- Pertussis toxin, a bacterial virulence factor, mediates cell binding.
- Eukaryotic selectins are cell adhesion molecules involved in leukocyte trafficking during inflammation.
- Selectins bind to carbohydrates on opposing cell surfaces.
Purpose of the Study:
- To investigate the molecular mimicry between pertussis toxin subunits and eukaryotic selectins.
- To determine if pertussis toxin subunits can interfere with selectin-mediated cell adhesion.
- To explore the functional consequences of this mimicry on leukocyte function.
Main Methods:
- Comparative analysis of amino acid sequences between pertussis toxin subunits (S2, S3) and selectin lectin domains.
- In vitro assays using purified pertussis toxin subunits and synthetic peptides.
- Experiments measuring neutrophil adherence to selectin-coated surfaces and endothelial cells.
- Assessment of leukocyte integrin CD11b/CD18 function.
Main Results:
- Pertussis toxin subunits S2 and S3 share sequence similarity with selectin lectin domains.
- Pertussis toxin subunits and derived peptides inhibited neutrophil adherence to selectins and endothelial cells.
- These molecules rapidly upregulated leukocyte integrin CD11b/CD18 function.
Conclusions:
- Prokaryotic adhesive ligands, like pertussis toxin, can mimic eukaryotic selectins.
- This molecular mimicry provides a mechanism for microbial pathogenesis by interfering with leukocyte trafficking.
- The findings link bacterial adhesion strategies to fundamental immune cell functions.