title: Assessment of the neutrophilic antibody-dependent respiratory burst (ADRB) response to Plasmodium falciparum.
abstract: Semi-immunity against Pf malaria is based on a combination of cellular and humoral immune responses. PMNs and IgGs are considered important components of this process, but the underlying mechanisms are unclear. We investigated the neutrophilic ADRB by analyzing the production of ROS in response to Pf antigen-specific IgGs bound to solid-phase immobilized antigens (sADRB) or whole merozoites (mADRB). We found that the PMN stimulations in each assay were based on different underlying mechanisms, demonstrating the importance of the assay set-up for the evaluation of antibody-triggered PMN responses. In the sADRB assay, ROS were produced externally, and by specific blocking of CD32(a)/FcγRII(a), the immediate neutrophilic response was abolished, whereas the removal of CD16(b)/FcγRIII(b) had no substantial effect. The key role of CD32(a) was confirmed using CD16(b)-deficient PMNs, in which similar changes of neutrophilic ADRB profiles were recorded after treatment. In the mADRB assay, ROS were produced almost exclusively within the cell, suggesting that the underlying mechanism was phagocytosis. This was confirmed using an additional phagocytosis assay, in which PMNs specifically ingested merozoites opsonized with Ghanaian plasma IgGs, seven times more often than merozoites opsonized with European plasma IgGs (P<0.001). Our data show that assay set-ups used to evaluate the responses of PMNs and perhaps other effector cells must be chosen carefully to evaluate the appropriate cellular responses. Our robust, stable, and well-characterized methods could therefore be useful in malaria vaccine studies to analyze the antimalarial effector function of antibodies.
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany; Rheinisch-Westfälische Technische Hochschule Aachen University, Institute for Molecular Biotechnology, Aachen, Germany; and.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Kapelski
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany;
authors.forename: Torsten
authors.initials: T
authors.lastname: Klockenbring
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany; Rheinisch-Westfälische Technische Hochschule Aachen University, Institute for Molecular Biotechnology, Aachen, Germany; and.
authors.forename: Rainer
authors.initials: R
authors.lastname: Fischer
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany; Institute for Applied Medical Engineering at Rheinisch-Westfälische Technische Hochschule Aachen University and Hospital, Department of Experimental Medicine and Immunotherapy, Aachen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Barth
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany; Rheinisch-Westfälische Technische Hochschule Aachen University, Institute for Molecular Biotechnology, Aachen, Germany; and rolf.fendel@ime.fraunhofer.de.
authors.forename: Rolf
authors.initials: R
authors.lastname: Fendel
mesh_terms: D000328:Adult; D000913:Antibodies, Protozoan / Q000097:blood / Q000276:immunology*; D000953:Antigens, Protozoan / Q000276:immunology; D005060:Europe; D005260:Female; D005869:Ghana; D006801:Humans; D055767:Immobilized Proteins; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D008297:Male; D052940:Merozoites / Q000276:immunology; D009504:Neutrophils / Q000276:immunology*; D009895:Opsonin Proteins / Q000276:immunology; D010587:Phagocytosis; D010949:Plasma / Q000276:immunology; D010963:Plasmodium falciparum / Q000254:growth & development / Q000276:immunology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D017452:Receptors, IgG / Q000037:antagonists & inhibitors / Q000276:immunology; D016897:Respiratory Burst; D052939:Schizonts / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; C499173:FCGR2B protein, human; C080568:Fc gamma receptor IIA; D055767:Immobilized Proteins; D007074:Immunoglobulin G; D009895:Opsonin Proteins; D017382:Reactive Oxygen Species; D017452:Receptors, IgG
keywords: cellular immune response; malaria; polymorphonuclear neutrophil granulocyte