title: Characterization of the interactions of the pneumolysoid, Δ6 PLY, with human neutrophils in vitro.
abstract: The pneumolysin toxoid, Δ6 PLY, is a prototype pneumococcal protein vaccine candidate. However, its potentially detrimental residual pro-inflammatory interactions with human neutrophils are unknown. In the current study the effects of the toxoid (8-1000 ng/ml) have been compared with those of wild-type pneumolysin (WT/PLY, 8 ng/ml) on neutrophil cytosolic Ca(2+) fluxes, generation of leukotriene B(4) (LTB(4)), and release of matrix metalloproteinase-9 (MMP-9), using spectrofluorimetric, and ELISA procedures (LTB(4) and MMP-9) respectively. Exposure of neutrophils to WT/PLY resulted in influx of Ca(2+) and significant (P<0.05) release of MMP-9 and generation of LTB(4). However, treatment of the cells with Δ6 PLY at concentrations of up to 1000 ng/ml had only trivial effects on Ca(2+) influx and no effects on either release of MMP-9 or LTB(4) production. The observed absence of pro-inflammatory interactions of Δ6 PLY with neutrophils is clearly an important property of this pneumococcal protein vaccine candidate.
authors.affiliation: MRC Unit for Inflammation and Immunity, Department of Immunology, University of Pretoria and Tshwane Academic Division of the National Health Laboratory Service, Pretoria, South Africa. riana.cockeran@up.ac.za
authors.forename: R
authors.initials: R
authors.lastname: Cockeran
authors.forename: H C
authors.initials: HC
authors.lastname: Steel
authors.forename: A J
authors.initials: AJ
authors.lastname: Theron
authors.forename: T J
authors.initials: TJ
authors.lastname: Mitchell
authors.forename: C
authors.initials: C
authors.lastname: Feldman
authors.forename: R
authors.initials: R
authors.lastname: Anderson
mesh_terms: D001426:Bacterial Proteins / Q000276:immunology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D007975:Leukotriene B4 / Q000096:biosynthesis*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D018375:Neutrophil Activation; D009504:Neutrophils / Q000276:immunology*; D013301:Streptolysins / Q000276:immunology*; D014121:Toxoids / Q000276:immunology
chemical_list: D001426:Bacterial Proteins; D013301:Streptolysins; D014121:Toxoids; C032290:plY protein, Streptococcus pneumoniae; D007975:Leukotriene B4; D020780:Matrix Metalloproteinase 9; D002118:Calcium