PORE-FORMING LEUCOTOXINS FROM STAPHYLOCOCCUS-AUREUS - TARGET-CELL VARIABILITY AND 2 PHARMACOLOGICAL PHENOMENONS

The staphylococcal bi-component leucotoxins constitute a family includ ed in the super-family of the P-sheet-structured pore-forming toxins. They may be produced by Staphylococcus aureus and by Staphylococcus in ter medius and their target cells vary according to the molecules. The mode of action proceeds by the sequential binding of the class S prot eins, then by that of the class F proteins at the surface of the membr anes. Then, the activation of cellular calcium-channels precedes the p ore formation which seems to be sensitive to several monovalent cation s. The cell response is inflammatory and includes the neosynthesis as well as the secretion of leucotriene B4, interleukine-8, histamine. Th e injection of leucotoxins to rabbits generates cell chemotactism, vas odilatation, and tissue necrosis. The association of the production of leucotoxins with clinical syndroms concerns several aspects of the pa thology of S. aureus, and confers to these leucotoxins an important ro le of virulence factors.