This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bhakdi, S Articles by Füssle, R Search for Related Content PubMed PubMed Citation Articles by Bhakdi, S Articles by Füssle, R

 Previous Article  |  Next Article 

Infect Immun. 1984 November; 46(2): 318-323

Correlation between toxin binding and hemolytic activity in membrane damage by staphylococcal alpha-toxin.

ABSTRACT

The binding of Staphylococcus aureus alpha-toxin to rabbit and human erythrocytes was studied by hemolytic assays and sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblotting. Hemolytic assays showed that toxin binding to 10% cell suspensions at neutral pH was very ineffective in the concentration range 3 X 10(-8) to 3 X 10(-7) M (1 to 10 micrograms/ml), and less than 5% of added toxin became cell bound. However, binding was augmented as toxin levels were raised, abruptly increasing to 50 to 60% at 2 X 10(-6) to 3 X 10(-6) M (60 to 100 micrograms/ml). When rabbit erythrocytes were lysed with 1 to 5 micrograms of toxin per ml, both monomeric and hexameric forms of the toxin could be detected on the membranes by sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblotting. In contrast, human erythrocytes treated with 1 to 6 micrograms of toxin per ml did not lyse, and membrane-bound toxin was not detectable. When toxin concentrations were raised to 30 to 100 micrograms/ml, human erythrocytes also lysed and toxin hexamers became membrane bound in comparable amounts as on rabbit cell membranes. Lowering the pH led to a marked increase in susceptibility of human, but not rabbit erythrocytes towards alpha-toxin. When human cells were lysed at pH 5.0 with 5 micrograms of toxin per ml, membrane-bound hexameric toxin became detectable. The demonstrated correlation between the presence of hexameric, cell-bound toxin and hemolytic activity supports the channel concept of toxin-mediated cytolysis. The results also show that toxin binding does not exhibit overall characteristics of a simple receptor-ligand interaction.

This article has been cited by other articles:

• Dinges, M. M., Orwin, P. M., Schlievert, P. M. (2000). Exotoxins of Staphylococcus aureus. Clin. Microbiol. Rev. 13: 16-34 [Abstract] [Full Text]  
• Valeva, A., Schnabel, R., Walev, I., Boukhallouk, F., Bhakdi, S., Palmer, M. (2001). Membrane Insertion of the Heptameric Staphylococcal alpha -Toxin Pore. A DOMINO-LIKE STRUCTURAL TRANSITION THAT IS ALLOSTERICALLY MODULATED BY THE TARGET CELL MEMBRANE. J. Biol. Chem. 276: 14835-14841 [Abstract] [Full Text]