Interaction of the two components of leukocidin from Staphylococcus aureus with human polymorphonuclear leukocyte membranes: sequential binding and subsequent activation

Abstract

The sequential interaction between the two components S and F of leukocidin from Staphylococcus aureus and the membrane of human polymorphonuclear neutrophils has been investigated in the presence of 1 mM Ca2+. With 125I-labeled components, it has been shown that binding of the F component occurred only after binding of the S component. The kinetic constants of binding of both components were not statistically different (Kd, approximately 5 nM; Bm, approximately 35,000 molecules per cell), and both Hill coefficients were 1. The application of increasing concentrations of leukocidin provoked a dose-dependent secretion of the granule content, as determined by hexosaminidase and lysozyme activity measurements. Furthermore, the separate perfusion of S and F components on human polymorphonuclear neutrophils deposited on a filter induced secretion of the granules content only when the perfusion of the S component preceded that of the F component. We conclude, therefore, that (i) S-component binding is a prerequisite for F-component binding and for subsequent activation of polymorphonuclear neutrophils and (ii) there is a specific binding site for the S component in the plasma membrane.

Staphylococcus aureus toxin LukSF dissociates from its membrane receptor target to enable renewed ligand sequestration

“…We did not observe any binding of mF* on the same cells (Fig. 1C, D), which is consistent with previous observations that LukF, in the absence of LukS, does not interact with PMN (16). The unlabeled mS inhibited binding of mS* in a dose-dependent fashion (Fig.…”

“…PVL is a prophage-encoded bicomponent, b-barrel pore-forming toxin (PFT) comprising protein subunits Luk components S and F (LukS and LukF, respectively). Binding of LukS and LukF to the surface of target cells induces formation of the pore; chemical and genetic analysis suggests that the resulting complex consists of a lytic pore-forming hetero-octamer (15,16). Stoichiometric analysis in vitro of this complex suggests it is an octamer of 4-plus-4 subunits (17).…”

Sublytic concentrations of Staphylococcus aureus Panton-Valentine leukocidin alter human PMN gene expression and enhance bactericidal capacity

“…Sublytic concentrations of PVL elicit numerous cellular responses, including release of MPO and chemotactic molecules, such as IL-8 and LTB 4 [13][14][15][16]. PMNs exposed to PVL undergo granule exocytosis and produce ROS following stimulation with fMLF [17].…”

Biology and management of methicillin resistant Staphylococcus aureus in cystic fibrosis

“…61 Panton-Valentine leukocidin induces necrosis of neutrophils, monocytes, and macrophages by binding to specific membrane receptors and forming a membrane perforating octamer. 62 Further, PVL induces exocytosis of PMN granules contributing to surrounding tissue necrosis. 62 Studies performed in vitro suggest that PVL promotes inflammation by different mechanisms including upregulation of leukotriene B4, a potent chemotactic agent.…”

“…62 Further, PVL induces exocytosis of PMN granules contributing to surrounding tissue necrosis. 62 Studies performed in vitro suggest that PVL promotes inflammation by different mechanisms including upregulation of leukotriene B4, a potent chemotactic agent. 63 In a French study conducted between 2008 and 2010, Filleron et al surveyed S. aureus isolates obtained from pediatric inpatients and outpatients.…”