lewis-x-antigen has been researched along with Hemolysis* in 2 studies
2 other study(ies) available for lewis-x-antigen and Hemolysis
| Article | Year |
|---|---|
The cholesterol-dependent cytolysins pneumolysin and streptolysin O require binding to red blood cell glycans for hemolytic activity.
The cholesterol-dependent cytolysin (CDC) pneumolysin (Ply) is a key virulence factor of Streptococcus pneumoniae. Membrane cholesterol is required for the cytolytic activity of this toxin, but it is not clear whether cholesterol is the only cellular receptor. Analysis of Ply binding to a glycan microarray revealed that Ply has lectin activity and binds glycans, including the Lewis histo-blood group antigens. Surface plasmon resonance analysis showed that Ply has the highest affinity for the sialyl LewisX (sLeX) structure, with a K(d) of 1.88 × 10(-5) M. Ply hemolytic activity against human RBCs showed dose-dependent inhibition by sLeX. Flow cytometric analysis and Western blots showed that blocking binding of Ply to the sLeX glycolipid on RBCs prevents deposition of the toxin in the membrane. The lectin domain responsible for sLeX binding is in domain 4 of Ply, which contains candidate carbohydrate-binding sites. Mutagenesis of these predicted carbohydrate-binding residues of Ply resulted in a decrease in hemolytic activity and a reduced affinity for sLeX. This study reveals that this archetypal CDC requires interaction with the sLeX glycolipid cellular receptor as an essential step before membrane insertion. A similar analysis conducted on streptolysin O from Streptococcus pyogenes revealed that this CDC also has glycan-binding properties and that hemolytic activity against RBCs can be blocked with the glycan lacto-N-neotetraose by inhibiting binding to the cell surface. Together, these data support the emerging paradigm shift that pore-forming toxins, including CDCs, have cellular receptors other than cholesterol that define target cell tropism. Topics: Amino Acid Sequence; Bacterial Proteins; Binding Sites; Carbohydrates; Cell Line, Tumor; Cell Membrane; Erythrocytes; Flow Cytometry; Glycolipids; Hemolysis; Humans; Lewis X Antigen; Molecular Sequence Data; Mutagenesis; Oligosaccharides; Polysaccharides; Protein Binding; Protein Conformation; Sequence Homology, Amino Acid; Streptolysins; Surface Plasmon Resonance | 2014 |
Modification at C6 of the terminal galactosyl residues of cobra venom factor abolishes anti-alpha-Gal antibody immunoreactivity without affecting functional activity.
The N-linked oligosaccharides of cobra venom factor (CVF) contain unique terminal alpha-galactosylated Lewis X structures. We have previously shown that CVF immobilized on nylon membranes binds naturally occurring human anti-alpha-Gal antibody. The present study shows that soluble CVF can effectively inhibit the binding of anti-alpha-Gal antibody to CVF-coated microtiter plates, indicating that the terminal alpha-galactosyl residues of the functionally active CVF are accessible to anti-alpha-Gal antibody binding. Modification of the terminal galactosyl residues of CVF by treatment with galactose oxidase and in situ derivatization of the generated aldehyde groups with hydrazides abolished the human anti-alpha-Gal antibody immunoreactivity without affecting the complement-activating activity. Topics: Animals; Antibodies; Elapid Venoms; Galactose; Galactose Oxidase; Glycoproteins; Guinea Pigs; Hemolysis; Humans; Hydrazines; Lewis X Antigen | 1998 |