Related Experiment Video
Updated: May 28, 2026
Legionella pneumophila Outer Membrane Vesicles: Isolation and Analysis of Their Pro-inflammatory Potential on Macrophages
Published on: February 22, 2017
Characterization of the interactions of the pneumolysoid, Δ6 PLY, with human neutrophils in vitro
R Cockeran1, H C Steel, A J Theron
1MRC 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
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.
