INTRODUCTION: We aimed to determine the neutralization of Neisseria meningitidis outer membrane vesicles (blebs) by humoral and cellular elements of whole blood. METHODS: The interaction of FITC-labeled blebs with monocytes was studied by spectrofluorometry. Blebs are able to induce an oxidative burst in neutrophils, and we evaluated the inhibitory effect of plasma on this process. RESULTS: Human plasma reduced the priming activity of blebs containing 1-3 ng/ml lipopolysaccharide (LPS) by 50-60% and bactericidal permeability increasing protein (BPI) reduced priming to background levels. A complete neutralization of LPS and blebs by plasma and BPI was measured using the limulus amebocyte lysate (LAL) assay. Furthermore, only 3% of blebs were cell-associated, while the remainder were in the supernatant. CONCLUSIONS: Plasma and BPI are able to neutralize blebs, with phagocytosis playing only a minor role. As such, we conclude that blebs do not behave like particles but more like free LPS.
INTRODUCTION: We aimed to determine the neutralization of Neisseria meningitidis outer membrane vesicles (blebs) by humoral and cellular elements of whole blood. METHODS: The interaction of FITC-labeled blebs with monocytes was studied by spectrofluorometry. Blebs are able to induce an oxidative burst in neutrophils, and we evaluated the inhibitory effect of plasma on this process. RESULTS:Human plasma reduced the priming activity of blebs containing 1-3 ng/ml lipopolysaccharide (LPS) by 50-60% and bactericidal permeability increasing protein (BPI) reduced priming to background levels. A complete neutralization of LPS and blebs by plasma and BPI was measured using the limulus amebocyte lysate (LAL) assay. Furthermore, only 3% of blebs were cell-associated, while the remainder were in the supernatant. CONCLUSIONS: Plasma and BPI are able to neutralize blebs, with phagocytosis playing only a minor role. As such, we conclude that blebs do not behave like particles but more like free LPS.
Authors: A Troelstra; P Antal-Szalmas; L A de Graaf-Miltenburg; A J Weersink; J Verhoef; K P Van Kessel; J A Van Strijp Journal: Infect Immun Date: 1997-06 Impact factor: 3.441
Authors: A Troelstra; B N Giepmans; K P Van Kessel; H S Lichenstein; J Verhoef; J A Van Strijp Journal: J Leukoc Biol Date: 1997-02 Impact factor: 4.962
Authors: Tom Sprong; Anne-Sophie W Møller; Anna Bjerre; Elisabeth Wedege; Peter Kierulf; Jos W M van der Meer; Petter Brandtzaeg; Marcel van Deuren; T E Mollnes Journal: Infect Immun Date: 2004-06 Impact factor: 3.441