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Heat-stable antigen (CD24) as ligand for mouse P-selectin
International Immunology
|July 1, 1994
Summary
Heat-stable antigen (HSA)/CD24, a heavily glycosylated cell surface molecule, exhibits glycoform heterogeneity. L2/HNK-1 modified HSA acts as a P-selectin ligand, mediating leukocyte-endothelial cell interactions.
Area of Science:
- Immunology
- Glycobiology
- Cell Biology
Background:
- Heat-stable antigen (HSA)/CD24 is a cell surface molecule with a small protein core and extensive glycosylation.
- The functional role of HSA-associated glycoconjugates is not fully understood due to its complex structure.
Purpose of the Study:
- To investigate the functional role of HSA-associated glycoconjugates.
- To characterize different forms of HSA and their interactions with selectins.
Main Methods:
- Isolation and characterization of different HSA glycoforms.
- Lectin analysis to determine carbohydrate composition and sialic acid linkage.
- ELISA and cell-based assays using P-selectin-IgG and E-selectin-IgG.
Main Results:
- HSA exhibits significant heterogeneity in carbohydrate composition and sialic acid linkage.
- Specific HSA glycoforms bind to P-selectin-IgG, but not E-selectin-IgG, in a cation-dependent manner.
- L2/HNK-1 positive HSA glycoforms bind P-selectin-IgG and mediate binding to P-selectin-expressing endothelial cells.
Conclusions:
- The L2/HNK-1 epitope on HSA is crucial for P-selectin binding.
- HSA, particularly in its L2/HNK-1 modified form on leukocytes, may serve as a ligand for P-selectin on endothelial cells or platelets, influencing cell adhesion.