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Michelin MA, Crott LSP, Assis-Pandochi AI, Coimbra TM, Teixeira JE, Barbosa JE. Influence of the electric charge of the antigen and the immune complex (IC) lattice on the IC activation of human complement. Int J Exp Pathol 2002; 83:105-10. [PMID: 12084047 PMCID: PMC2517671 DOI: 10.1046/j.1365-2613.2002.00224.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to understand the mechanism of complement (C) activation by immune complexes (ICs), the anti-complementary effect of ICs containing cationized antigens was compared in vitro to that using ICs formed by native antigens. ICs were prepared with affinity-purified rabbit polyclonal IgG antibovine serum albumin (BSA) antibody and either native BSA (isoelectric point 4.2) or BSA rendered cationic by treatment with ethylenediamine (isoelectric point 9.4). Native and cationized antigens were characterized by isoelectric focusing. ICs containing anti-BSA IgG or F(ab')2, formed either at equivalence or in excess of native or cationized antigen, were submitted to ultracentrifugation in a sucrose gradient for mesh size determination. The anti-complementary effect of ICs was evaluated by kinetic determination of haemolytic activity of human serum on haemolysin-sensitized sheep red blood cells. In conditions of antigen excess, the ICs formed by cationized BSA were significantly more efficient in activating human complement than those formed by native antigen. This higher activity was dependent on cationized antigen complexed with complete antibody molecules, as non-complexed cationized BSA or ICs prepared with F(ab')2 fragments were inactive under the same experimental conditions. Furthermore, this difference did not depend on the mesh size of the immune complexes. Our results suggest that the balance between antigen, antibody and C may be of importance in vivo for the onset and course of infections and other pathological processes involving IC formation. ICs containing cationized antigens should be proven of value in experimental models for studies on the regulation of C activation.
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Affiliation(s)
- M A Michelin
- Departamento de Ciências Biológicas, Faculdade de Medicina do Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
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Trevani AS, Andonegui G, Giordano M, López DH, Gamberale R, Minucci F, Geffner JR. Extracellular Acidification Induces Human Neutrophil Activation. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.162.8.4849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
In the current work, we evaluated the effect of extracellular acidification on neutrophil physiology. Neutrophils suspended in bicarbonate-buffered RPMI 1640 medium adjusted to acidic pH values (pH 6.5–7.0) underwent: 1) a rapid transient increase in intracellular free calcium concentration levels; 2) an increase in the forward light scattering properties; and 3) the up-regulation of surface expression of CD18. By contrast, extracellular acidosis was unable to induce neither the production of H2O2 nor the release of myeloperoxidase. Acidic extracellular pH also modulated the functional profile of neutrophils in response to conventional agonists such as FMLP, precipiting immune complexes, and opsonized zymosan. It was found that not only calcium mobilization, shape change response, and up-regulation of CD18 expression but also production of H2O2 and release of myeloperoxidase were markedly enhanced in neutrophils stimulated in acidic pH medium. Moreover, extracellular acidosis significantly delayed neutrophil apoptosis and concomitantly extended neutrophil functional lifespan. Extracellular acidification induced an immediate and abrupt fall in the intracellular pH, which persisted over the 240-s analyzed. A similar abrupt drop in the intracellular pH was detected in cells suspended in bicarbonate-supplemented PBS but not in those suspended in bicarbonate-free PBS. A role for intracellular acidification in neutrophil activation is suggested by the fact that only neutrophils suspended in bicarbonate-buffered media (i.e., RPMI 1640 and bicarbonate-supplemented PBS) underwent significant shape changes in response to extracellular acidification. Together, our results support the notion that extracellular acidosis may intensify acute inflammatory responses by inducing neutrophil activation as well as by delaying spontaneous apoptosis and extending neutrophil functional lifespan.
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Affiliation(s)
- Analía S. Trevani
- *Laboratory of Immunology, Institute of Hematologic Research, National Academy of Medicine, and
- †Department of Microbiology, Buenos Aires University School of Medicine, Buenos Aires, Argentina
| | - Graciela Andonegui
- *Laboratory of Immunology, Institute of Hematologic Research, National Academy of Medicine, and
| | - Mirta Giordano
- *Laboratory of Immunology, Institute of Hematologic Research, National Academy of Medicine, and
| | - Daniel H. López
- *Laboratory of Immunology, Institute of Hematologic Research, National Academy of Medicine, and
| | - Romina Gamberale
- *Laboratory of Immunology, Institute of Hematologic Research, National Academy of Medicine, and
| | - Fernando Minucci
- *Laboratory of Immunology, Institute of Hematologic Research, National Academy of Medicine, and
| | - Jorge R. Geffner
- *Laboratory of Immunology, Institute of Hematologic Research, National Academy of Medicine, and
- †Department of Microbiology, Buenos Aires University School of Medicine, Buenos Aires, Argentina
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Gamberale R, Giordano M, Trevani AS, Andonegui G, Geffner JR. Modulation of Human Neutrophil Apoptosis by Immune Complexes. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.7.3666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
In the present study we examined whether immune complexes (IC) are able to modulate human neutrophil apoptosis. We observed different effects depending on the type of IC employed. Precipitating IC (pIC) and Ab-coated erythrocytes (E-IgG) triggered a marked stimulation of apoptosis, while heat-aggregated IgG and soluble IC, significantly delayed spontaneous apoptosis. Blocking Abs directed to Fcγ receptor type II (FcγRII), but not to FcγRIII, markedly diminished the acceleration of apoptosis triggered by either pIC or E-IgG, supporting a critical role for FcγRII in apoptosis stimulation. This phenomenon, on the other hand, does not appear to involve IC phagocytosis or the participation of CR3. Acceleration of neutrophil apoptosis triggered by either pIC or E-IgG seems to require the activation of the respiratory burst, as suggested by 1) the ability of catalase to prevent apoptosis stimulation; 2) the effect of azide, an heme enzyme inhibitor, which dramatically enhanced apoptosis induced by pIC or E-IgG; and 3) the inability of pIC or E-IgG to accelerate apoptosis of neutrophils isolated from CGD patients. It is well established that IC affect the course of inflammation by inducing the release of inflammatory cytokines, proteolytic enzymes, oxidative agents, and other toxic molecules. Our results suggest that IC may also affect the course of inflammation by virtue of their ability to modulate neutrophil apoptosis.
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Affiliation(s)
- Romina Gamberale
- *Laboratory of Immunology, Institute of Hematologic Research, National Academy of Medicine, and
- †Department of Microbiology, Buenos Aires University School of Medicine, Buenos Aires, Argentina
| | - Mirta Giordano
- *Laboratory of Immunology, Institute of Hematologic Research, National Academy of Medicine, and
- †Department of Microbiology, Buenos Aires University School of Medicine, Buenos Aires, Argentina
| | - Analía S. Trevani
- *Laboratory of Immunology, Institute of Hematologic Research, National Academy of Medicine, and
- †Department of Microbiology, Buenos Aires University School of Medicine, Buenos Aires, Argentina
| | - Graciela Andonegui
- *Laboratory of Immunology, Institute of Hematologic Research, National Academy of Medicine, and
| | - Jorge R. Geffner
- *Laboratory of Immunology, Institute of Hematologic Research, National Academy of Medicine, and
- †Department of Microbiology, Buenos Aires University School of Medicine, Buenos Aires, Argentina
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Ginsburg I, Kohen R. Cell damage in inflammatory and infectious sites might involve a coordinated "cross-talk" among oxidants, microbial haemolysins and ampiphiles, cationic proteins, phospholipases, fatty acids, proteinases and cytokines (an overview). Free Radic Res 1995; 22:489-517. [PMID: 7633573 DOI: 10.3109/10715769509150323] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- I Ginsburg
- Department of Oral Biology, Hebrew University, Hadassah School of Dental Medicine, Jerusalem, Israel
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