351
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Papadaki HA, Psyllaki M, Eliopoulos DG, Tsiroyianni A, Eliopoulos GD. Increased frequency and specific reactivity of serum antinuclear antibodies in patients with nonimmune chronic idiopathic neutropenia of adults. Acta Haematol 2001; 105:13-20. [PMID: 11340248 DOI: 10.1159/000046527] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This study describes the frequency of serum organ-specific and organ-nonspecific autoantibodies in 157 patients with nonimmune chronic idiopathic neutropenia of adults (NI-CINA). Forty-two age- and gender-matched volunteers were used as controls. We found that patients with NI-CINA had increased frequency of antinuclear antibodies (ANA) compared to controls (33.1 vs. 9.5%, p = 0.0025), and that ANA positivity inversely correlated with the number of circulating neutrophils (r = -0.2765, p < 0.0001). Speckled pattern of reactivity was seen in 84.6% of ANA-positive patients, and diffuse pattern in the remaining 15.4%. Patients had also increased levels of circulating immune complexes compared to controls (3.30 +/- 2.41 vs. 1.70 +/- 1.19 microg/ml, p = 0.0042), which inversely correlated with the number of circulating neutrophils (r = -0.2405, p = 0.0154) but not with the titer of ANA positivity. No significant differences were found between the patients and the normal controls in the frequency of positive tests for antibodies to dsDNA, Sm, nRNP, SSA, SSB and Scl-70 antigens, or for parietal cell antibodies, anti-neutrophil cytoplasmic antibodies (ANCA), anti-cardiolipin and anti-thyroid antibodies. Serum levels of rheumatoid factor, C-reactive protein (CRP) and complement factors C3 and C4 ranged within normal limits in the patients studied, but a highly significant correlation was noted between the levels of CRP and ANA positivity (r = 0.3936, p < 0.0001). These findings are suggestive of a chronic inflammation in NI-CINA patients which provides the antigenic stimulus for ANA production, and they further support our previously reported suggestion for the possible involvement of such a low-grade chronic inflammatory process in the pathogenesis of neutropenia in the affected subjects.
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Affiliation(s)
- H A Papadaki
- Department of Hematology, University Hospital of Heraklion, University of Crete School of Medicine, Heraklion, Crete, Greece
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352
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Navratil JS, Ahearn JM. Apoptosis, clearance mechanisms, and the development of systemic lupus erythematosus. Curr Rheumatol Rep 2001; 3:191-8. [PMID: 11352787 DOI: 10.1007/s11926-001-0018-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Cell death by apoptosis is an integral part of many biologic processes, including embryonic development, T- and B-cell selection, the elimination of potentially autoreactive lymphocytes in the periphery, and maintenance of lymphocyte homeostasis through activation-induced cell death. There is also increasing evidence that apoptosis may maintain immune tolerance and that it may be the process that generates the self antigens responsible for the initial development of autoimmunity. This review discusses some of the biochemical steps involved in the apoptotic process, how potentially immunogenic self antigens are generated during apoptosis, and the mechanisms by which the products of apoptosis are cleared and processed to avoid breaking immune tolerance.
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Affiliation(s)
- J S Navratil
- University of Pittsburgh School of Medicine, University of Pittsburgh Arthritis Institute, S705 Biomedical Science Tower, 3500 Terrace Street, Pittsburgh, PA 15261, USA
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353
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Scott RS, McMahon EJ, Pop SM, Reap EA, Caricchio R, Cohen PL, Earp HS, Matsushima GK. Phagocytosis and clearance of apoptotic cells is mediated by MER. Nature 2001; 411:207-11. [PMID: 11346799 DOI: 10.1038/35075603] [Citation(s) in RCA: 879] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Apoptosis is fundamental to the development and maintenance of animal tissues and the immune system. Rapid clearance of apoptotic cells by macrophages is important to inhibit inflammation and autoimmune responses against intracellular antigens. Here we report a new function for Mer, a member of the Axl/Mer/Tyro3 receptor tyrosine kinase family. mer(kd) mice with a cytoplasmic truncation of Mer had macrophages deficient in the clearance of apoptotic thymocytes. This was corrected in chimaeric mice reconstituted with bone marrow from wild-type animals. Primary macrophages isolated from mer(kd) mice showed that the phagocytic deficiency was restricted to apoptotic cells and was independent of Fc receptor-mediated phagocytosis or ingestion of other particles. The inability to clear apoptotic cells adequately may be linked to an increased number of nuclear autoantibodies in mer(kd) mice. Thus, the Mer receptor tyrosine kinase seems to be critical for the engulfment and efficient clearance of apoptotic cells. This has implications for inflammation and autoimmune diseases such as systemic lupus erythematosus.
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MESH Headings
- Animals
- Antibodies, Antinuclear/immunology
- Apoptosis/drug effects
- Bone Marrow Transplantation
- Cell Adhesion
- Cells, Cultured
- Crosses, Genetic
- Cytochalasin B/pharmacology
- Dexamethasone/pharmacology
- Female
- Flow Cytometry
- Immunohistochemistry
- Listeria monocytogenes/immunology
- Macrophages, Peritoneal/cytology
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/metabolism
- Macrophages, Peritoneal/ultrastructure
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Microscopy, Electron, Scanning
- Microspheres
- Mutation/genetics
- Phagocytosis
- Protein-Tyrosine Kinases/genetics
- Protein-Tyrosine Kinases/metabolism
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- Radiation Chimera/immunology
- Receptor Protein-Tyrosine Kinases
- Receptors, Fc/immunology
- Thymus Gland/cytology
- Thymus Gland/drug effects
- Thymus Gland/immunology
- Thymus Gland/ultrastructure
- c-Mer Tyrosine Kinase
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354
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Affiliation(s)
- M G Robson
- Rheumatology Section, Division of Medicine, Imperial College of Science, Technology and Medicine, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
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355
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Affiliation(s)
- V Verhasselt
- Laboratory of Experimental Immunology, Faculty of Medicine, Université Libre de Bruxelles, 808, route de Lennik, Bruxelles, 1070, Belgium
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356
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Rivadeneira DE, Grobmyer SR, Naama HA, Mackrell PJ, Mestre JR, Stapleton PP, Daly JM. Malnutrition-induced macrophage apoptosis. Surgery 2001; 129:617-25. [PMID: 11331454 DOI: 10.1067/msy.2001.112963] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Human and murine studies suggest protein-calorie malnutrition (PCM) results in significant host immunosuppression resulting in increased morbidity and mortality. Apoptosis has been implicated as an important mediator in the immunosuppression observed in several disease states. This study was designed to characterize macrophage apoptosis in a murine model of PCM and investigate components that regulate the apoptotic process, such as protein kinase C (PKC) and Bcl-2 activity. METHODS Swiss-Webster mice (n = 50) were randomly assigned to receive either a control (24% protein) or a PCM diet (0% protein) for 7 days. Peritoneal macrophages were harvested and detection of apoptosis was performed by terminal deoxy-transferase-mediated deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL) and propidium iodide DNA staining under baseline and pro-apoptotic conditions. Pro-apoptotic conditions included cells treated with tumor necrosis factor-alpha (TNF-alpha) (10 ng/mL), interferon-gamma (IFN-gamma) (10 ng/mL), and a combination of both agents. In addition, levels of PKC activity and expression of Bcl-2 and p53 protein were measured. RESULTS Peritoneal macrophages from PCM mice had a significantly greater amount of apoptosis at baseline and under stimulated conditions compared with controls. Levels of PCM apoptosis were elevated at baseline by TUNEL staining compared with macrophages from the control group (16.5% +/- 1.4%, versus 4.5% +/- 1.1%, P <.01). In addition, peritoneal macrophages from the malnourished animals were significantly more susceptible to the apoptotic effect of TNF-alpha and the effects of INF-gamma (27.3% +/- 2.1% and 31% +/- 1.4%) compared with control mice (5.5% +/- 0.7% and 7.2% +/- 0.5%, P <.01), respectively. Again, an increase in the baseline apoptosis rate was demonstrated in peritoneal macrophages from PCM mice compared with control fed mice (13.2% +/- 4.4% versus 4.3% +/- 3.1%, P <.01) as measured by propidium iodide staining. The combination of agents, TNF-alpha and INF-gamma, resulted in an additive apoptotic effect in the malnourished host compared with the control animals (43.4% +/- 4.7% versus 10.5% +/- 2.2%, P <.01), respectively. Furthermore, there was a significant decrease in the mean total PKC activity in the malnourished macrophages compared with results in controls (110,000 +/- 8000 versus 60,000 +/- 4000 cpm, P <.01). Similar changes were also observed in PKC cytosolic and membrane activity between both groups. In addition, Bcl-2 protein expression was significantly decreased in PCM animals compared with control animals. CONCLUSIONS Thus, peritoneal macrophages from PCM mice exhibit significantly greater levels of apoptosis at baseline and when stimulated with pro-apoptotic agents compared with controls. The propensity of macrophages from PCM mice to undergo apoptosis may be attributable in part to decreased PKC activity and Bcl-2 protein expression. These findings may help to explain the associated immune dysfunction observed in malnutrition.
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Affiliation(s)
- D E Rivadeneira
- Department of Surgery, New York Presbyterian Hospital-Cornell Campus, Weill Medical College of Cornell University, New York, NY, USA
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357
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El-Amine M, Melo ME, Scott DW. Gene therapy for tolerance and autoimmunity: soon to be fulfilled promises? Clin Immunol 2001; 99:1-6. [PMID: 11286536 DOI: 10.1006/clim.2000.4988] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- M El-Amine
- Department of Immunology, American Red Cross, Jerome H. Holland Laboratory, Rockville, Maryland 20855, USA
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358
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Pickering MC, Botto M, Taylor PR, Lachmann PJ, Walport MJ. Systemic lupus erythematosus, complement deficiency, and apoptosis. Adv Immunol 2001; 76:227-324. [PMID: 11079100 DOI: 10.1016/s0065-2776(01)76021-x] [Citation(s) in RCA: 405] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
MESH Headings
- Adolescent
- Adult
- Alleles
- Animals
- Antibody Formation
- Antigen-Antibody Complex/immunology
- Antigen-Antibody Complex/metabolism
- Apoptosis/immunology
- Autoantibodies/immunology
- Autoantigens/immunology
- Autoimmune Diseases/epidemiology
- Autoimmune Diseases/etiology
- Autoimmune Diseases/genetics
- Autoimmune Diseases/immunology
- Bias
- Carrier Proteins/genetics
- Child
- Child, Preschool
- Collectins
- Complement Activation
- Complement C1 Inactivator Proteins/deficiency
- Complement C1 Inactivator Proteins/genetics
- Complement C1q/deficiency
- Complement C1q/genetics
- Complement C1q/immunology
- Complement System Proteins/deficiency
- Complement System Proteins/genetics
- Complement System Proteins/physiology
- Disease Models, Animal
- Female
- Genetic Predisposition to Disease
- Genotype
- Guinea Pigs
- Humans
- Infant
- Lupus Erythematosus, Systemic/epidemiology
- Lupus Erythematosus, Systemic/etiology
- Lupus Erythematosus, Systemic/genetics
- Lupus Erythematosus, Systemic/immunology
- Male
- Mice
- Mice, Inbred MRL lpr
- Mice, Knockout
- Mice, Mutant Strains
- Middle Aged
- Models, Immunological
- Polymorphism, Genetic
- Receptors, Complement/chemistry
- Receptors, Complement/genetics
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Affiliation(s)
- M C Pickering
- Rheumatology Section, Imperial College School of Medicine, London, England
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359
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Bondanza A, Rovere P, Borri A, Caremoli ER, Guidetti A, Citterio G, Consogno G, Zimmermann VS, Rugarli C, Manfredi AA. Cytokine secretion associated with the clearance of apoptotic bodies in renal cell carcinoma patients. Int J Cancer 2001; 91:713-7. [PMID: 11267985 DOI: 10.1002/1097-0215(200002)9999:9999<::aid-ijc1096>3.0.co;2-g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The factors determining the outcome of immunotherapy in metastatic renal cell carcinoma (RCC) patients remain elusive. Macrophages from normal donors that phagocytose apoptotic cells secrete the immunosuppressive cytokine IL-10 in vitro. Conversely, IL-10 genetic deletion enhances the immunogenicity of apoptotic tumor cells in vivo. Elevated pre-treatment levels of IL-10 are associated with an unfavorable outcome of RCC. We examined whether the ability to release IL-10 by macrophages from RCC patients that phagocytosed apoptotic cells correlated with the outcome of immunotherapy. To this aim, we derived macrophages from 30 patients with metastatic RCC and from 21 healthy subjects (11 sex- and age-matched healthy controls and 10 younger donors). Patients either had a clinical response after immunotherapy, with a median survival after treatment of more than 18 months (n = 16), or were beginning immunotherapy after diagnosis of metastatic disease (n = 14). Macrophages from responding patients challenged with apoptotic cells released significantly less IL-10 than controls (p = 0.0075) and recently diagnosed patients (p = 0.0198), as ascertained by a 2-sided Student's t-test. This was not because macrophages from responding patients lost the ability to secrete IL-10, because antibody opsonization of apoptotic cells rescued IL-10 secretion. In contrast, macrophages from all groups of donors released similar amounts of TNF-alpha. The failure in IL-10 secretion by engulfing macrophages of responding subjects may exalt the immunogenicity of dying tumor cells, contributing to the success of immunotherapy.
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Affiliation(s)
- A Bondanza
- Laboratory of Tumor Immunology and Cancer Immunotherapy and Gene Therapy Program, H. San Raffaele Scientific Institute, Milan, Italy
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360
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Navratil JS, Watkins SC, Wisnieski JJ, Ahearn JM. The globular heads of C1q specifically recognize surface blebs of apoptotic vascular endothelial cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:3231-9. [PMID: 11207277 DOI: 10.4049/jimmunol.166.5.3231] [Citation(s) in RCA: 177] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Complement protein C1q is required to maintain immune tolerance. The molecular mechanism responsible for this link has not been determined. We have previously demonstrated that C1q binds directly and specifically to surface blebs of apoptotic human keratinocytes, suggesting that it may participate in clearance of self Ags generated during programmed cell death. Here, we demonstrate that C1q also binds directly to apoptotic blebs of vascular endothelial cells and PBMC. These apoptotic cells are recognized by the globular heads of C1q, which bind specifically to the surface blebs, and deposition increases as the blebs mature on the cell surface. These observations suggest that C1q may participate in the clearance of apoptotic cells from the circulation and from the walls of the vascular lumen. The interaction of surface blebs with the globular heads of C1q suggests that surface blebs may be capable of directly activating the classical pathway of complement under certain circumstances, generating C4- and C3-derived ligands for receptors such as CR1, CR2, CR3, and CR4. Appropriate recognition of apoptotic cells by C1q and targeted clearance of the molecular contents of surface blebs to complement receptors may be critical for the maintenance of immune tolerance.
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MESH Headings
- Apoptosis/immunology
- Cells, Cultured
- Complement C1q/chemistry
- Complement C1q/metabolism
- Complement Pathway, Classical
- Endothelium, Vascular/cytology
- Endothelium, Vascular/immunology
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/ultrastructure
- Fluorescent Antibody Technique, Indirect
- HeLa Cells
- Humans
- Leukocytes, Mononuclear/cytology
- Leukocytes, Mononuclear/immunology
- Leukocytes, Mononuclear/metabolism
- Leukocytes, Mononuclear/ultrastructure
- Microscopy, Confocal
- Microscopy, Fluorescence
- Protein Binding/immunology
- Protein Structure, Tertiary
- Structure-Activity Relationship
- Surface Properties
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Affiliation(s)
- J S Navratil
- Immunology Graduate Training Program, Departments of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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361
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Masago R, Aiba-Masago S, Talal N, Zuluaga FJ, Al-Hashimi I, Moody M, Lau CA, Peck AB, Brayer J, Humphreys-Beher MG, Dang H. Elevated proapoptotic Bax and caspase 3 activation in the NOD.scid model of Sjögren's syndrome. ARTHRITIS AND RHEUMATISM 2001; 44:693-702. [PMID: 11263785 DOI: 10.1002/1529-0131(200103)44:3<693::aid-anr119>3.0.co;2-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Salivary gland epithelial cells in patients with Sjögren's syndrome (SS) and in NOD and NODscid mice express Fas and Fas ligand, and these cells die from apoptosis. To elucidate the intracellular molecular mechanisms responsible for this salivary gland epithelial cell apoptosis, expression of the Bcl-2 family of proteins (Bcl-2, Bcl-xL, Bax) and caspase (caspases 3 and 8) was studied in young (ages 8-10 weeks) and old (ages 17-28 weeks) NOD and NOD.scid mice. METHODS Sections of frozen salivary gland tissue were obtained from NOD and NOD.scid mice and from the lip biopsy material of SS patients. Immunohistochemistry or Western blot analysis was performed to assess the apoptotic-associated proteins. RESULTS Levels of Bax and caspase 3 were elevated in the epithelial cells of glands from old NOD mice, but not in those from young NOD mice. In contrast, epithelial cells from both young and old NOD.scid mice exhibited strong expression of Bax and caspase 3. Western blot analysis showed that the activated form of caspase 3 was increased 2-5-fold in the glands from old NOD, old NOD.scid, and young NOD.scid mice compared with those from young NOD mice. Caspase 3 was also significantly elevated (P < 0.01) in SS patients whose focus scores were grade 3 or 4. In the SS patients' biopsy tissue and in the mouse glands, cells with fragmented DNA were positive for caspase 3. CONCLUSION These results demonstrate that salivary gland epithelial cells in NOD and NOD.scid mice overexpress the proapoptotic molecules Bax and caspase 3. Bax could be the gene responsible for initiation of caspase activation, epithelial cell destruction, and lymphocyte glandular localization in SS.
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Affiliation(s)
- R Masago
- The University of Texas Health Science Center, San Antonio, USA
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362
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Abstract
As a part of innate immunity, soluble host proteins called opsonins, which include complement ligands and immunoglobulins, initially coat microorganisms that penetrate the mammalian sterile milieu. The main purpose of opsonization is to allow subsequent clearance of opsonized particles by specific receptors on the surface of leukocytes. Similarly, several proteins that may act as opsonins and have a role in uptake of apoptotic cells and bodies include thrombospondin I, the complement system, beta 2GPI, immunoglobulins, CRP, and some unidentified others. The surface changes that lead to opsonization include the appearance of phosphatidylserine that acts as an activator molecule for some known opsonins as the complement system and beta 2GPI. The consequence of altered opsonization is demonstrated by the development of autoimmunity in C1q deficient mice, and the pro-inflammatory response by macrophages ingesting apoptotic cell opsonized by an autoantibody.
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Affiliation(s)
- D Mevorach
- Laboratory for Cellular and Molecular Immunology, Tel-Aviv Medical Center, Hadassah Medical Center and the Hebrew University, Jerusalem, Israel.
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363
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Gensler TJ, Hottelet M, Zhang C, Schlossman S, Anderson P, Utz PJ. Monoclonal antibodies derived from BALB/c mice immunized with apoptotic Jurkat T cells recognize known autoantigens. J Autoimmun 2001; 16:59-69. [PMID: 11221997 DOI: 10.1006/jaut.2000.0464] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It has been postulated that post-translational modifications and relocalization of proteins during apoptosis may lead to presentation of these molecules to the immune system in such a way that normal mechanisms of tolerance are bypassed. In the present study, Jurkat cells were induced to undergo apoptosis by treatment with the chemotherapeutic agent Ara-C. BALB/c mice were then immunized with the apoptotic cells and hybridomas were generated. Using an indirect immunofluorescence assay, the monoclonal antibodies produced were screened by flow cytometry for those monoclonal antibodies demonstrating reactivity with permeabilized apoptotic Jurkat cells but not with non-permeabilized normal or apoptotic Jurkat cells. Of 281 monoclonal antibodies, 20 monoclonal antibodies with these properties were selected for further analysis. Using 32P- or 35S-metabolically labelled Jurkat cells, these selected monoclonal antibodies were screened for their ability to recognize autoantigens by immunoprecipitation and Western blotting. Well characterized autoimmune sera were then used to confirm the identity of autoantigens by immunoblotting. We demonstrate that immunization of normal mice with apoptotic Jurkat cells results in the formation of antibodies targeting multiple autoantigens or autoantigen complexes, including Ku, rRNPs, snRNPs and vimentin. These findings are consistent with the hypothesis that apoptosis can contribute to the development of autoimmunity.
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Affiliation(s)
- T J Gensler
- The Department of Medicine, Division of Rheumatology, Immunology and Allergy, Brigham & Women's Hospital, Boston, MA 02115, USA
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364
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Botto M. Links between complement deficiency and apoptosis. ARTHRITIS RESEARCH 2001; 3:207-10. [PMID: 11438036 PMCID: PMC128896 DOI: 10.1186/ar301] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/29/2000] [Revised: 03/12/2001] [Accepted: 03/14/2001] [Indexed: 01/17/2023]
Abstract
Deficiency in the classical pathway complement components displays a hierarchical association with the development of systemic lupus erythematosus (SLE). In addition, SLE causes consumption of complement. C1q- and C4-deficient mice develop a lupus-like disease and exhibit impaired clearance of apoptotic cells. The autoantigens targeted in SLE have been localised to the surface of apoptotic cells, which may be the source of these antigens. Although apoptosis was originally thought to be an immunologically inert process, dendritic cells can present epitopes derived from apoptotic cells, and immunization with apoptotic cells leads to the generation of autoantibodies. These findings taken together indicate that a defect in complement-dependent clearance of apoptotic cells may increase susceptibility to the development of autoimmunity.
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Affiliation(s)
- M Botto
- Rheumatology Section, Division of Medicine, Imperial College School of Medicine, London, UK.
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365
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Bijl M, Horst G, Limburg PC, Kallenberg CG. Anti-CD3-induced and anti-Fas-induced apoptosis in systemic lupus erythematosus (SLE). Clin Exp Immunol 2001; 123:127-32. [PMID: 11168009 PMCID: PMC1905956 DOI: 10.1046/j.1365-2249.2001.01418.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Disturbances in apoptosis or in the clearance of apoptotic material might result in increased presentation of autoantigens which could be relevant to the pathogenesis of SLE. Data concerning defects in apoptosis in SLE are conflicting. To determine whether intrinsic defects in apoptosis induction occur in SLE irrespective of disease activity, we examined anti-CD3 and anti-Fas-induced apoptosis in vitro in SLE patients with inactive disease. Isolated peripheral blood lymphocytes (PBL) from 13 SLE patients and 14 healthy controls were incubated with anti-CD3, and, subsequently, after up-regulation of membrane Fas following anti-CD3 incubation, with anti-Fas. Expression of Fas and levels of apoptosis as detected by annexin V and propidium iodide staining were assessed by flow cytometry before and after the respective incubations. Fas expression on freshly isolated lymphocytes of SLE patients was increased whereas levels of circulating apoptotic cells were comparable between patients and controls. Stimulation with anti-CD3 resulted in up-regulation of membrane Fas in patients and in controls. In vitro induction of apoptosis by anti-CD3 as well as by anti-Fas occurred both in SLE patients and controls, and was higher in SLE patients after incubation with anti-CD3 as well as with anti-Fas. We conclude that Fas expression and in vitro induction of apoptosis are increased in SLE even in the absence of disease activity.
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Affiliation(s)
- M Bijl
- Department of Clinical Immunology, University Hospital, Groningen, The Netherlands
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366
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Mohan C, Liu F, Xie C, Williams RC. Anti-subnucleosome reactivities in systemic lupus erythematosus (SLE) patients and their first-degree relatives. Clin Exp Immunol 2001; 123:119-26. [PMID: 11168008 PMCID: PMC1905960 DOI: 10.1046/j.1365-2249.2001.01417.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antibodies specific for dsDNA appear to have different genetic origins and pathogenic consequences, compared with histone/dsDNA-specific antibodies, in a recently described murine model. The purpose of this study was to examine if this is also true in human lupus. Sera from 40 SLE families (comprising 40 probands and 153 first-degree relatives), and 45 normal adult controls were assayed for the levels of anti-dsDNA, anti-H1/dsDNA, anti-H2A/H2B/dsDNA, and anti-H3/H4/dsDNA autoantibodies by ELISA. Both the probands and the first-degree relatives exhibited significantly increased levels of antinuclear antibodies (ANA) targeting the different subnucleosomal epitopes. Importantly, probands with anti-dsDNA antibodies had a significantly higher incidence of renal disease compared with those with just anti-H2A/H2B/dsDNA antibodies, in resonance with murine studies. The frequency of anti-dsDNA and anti-H2A/H2B/DNA ANA among the first-degree relatives was 11.8% and 18.3%, respectively. Surprisingly, whereas probands with anti-dsDNA ANA had families with several seropositive members, first-degree relatives of patients with anti-H2A/H2B/DNA ANA (but not anti-dsDNA ANA) were uniformly ANA-free. These findings suggest that anti-dsDNA ANA in lupus may not only have worse disease associations, they may also have very different genetic origins, compared with anti-H2A/H2B/DNA (or anti-nucleosome) ANA.
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Affiliation(s)
- C Mohan
- Simmons Arthritis Research Center and the Center for Immunology, University of Texas South-western Medical School, Dallas, TX 75390-8884, USA
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367
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Chen Z, Koralov SB, Kelsoe G. Complement C4 inhibits systemic autoimmunity through a mechanism independent of complement receptors CR1 and CR2. J Exp Med 2000; 192:1339-52. [PMID: 11067882 PMCID: PMC2193358 DOI: 10.1084/jem.192.9.1339] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The complement system enhances antibody responses to T-dependent antigens, but paradoxically, deficiencies in C1 and C4 are strongly linked to autoantibody production in humans. In mice, disruption of the C1qa gene also results in spontaneous autoimmunity. Moreover, deficiencies in C4 or complement receptors 1 and 2 (CR1/CR2) lead to reduced selection against autoreactive B cells and impaired humoral responses. These observations suggest that C1 and C4 act through CR1/CR2 to enhance humoral immunity and somehow suppress autoimmunity. Here we report high titers of spontaneous antinuclear antibody (ANA) in C4(-/)- mice. This systemic lupus erythematosus-like autoimmunity is highly penetrant; by 10 mo of age, all C4(-)(/)- females and most males produced ANA. In contrast, titers and frequencies of ANA in Cr2(-)(/)- mice, which are deficient in CR1 and CR2, never rose significantly above those in normal controls. Glomerular deposition of immune complexes (ICs), glomerulonephritis, and splenomegaly were observed in C4(-)(/)- but not Cr2(-)(/)- mice. C4(-)(/)-, but not Cr2(-)(/)-, mice accumulate activated T and B cells. Clearance of circulating ICs is impaired in preautoimmune C4(-)(/)-, but not Cr2(-)(/)-, mice. C4 deficiency causes spontaneous, lupus-like autoimmunity through a mechanism that is independent of CR1/CR2.
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MESH Headings
- Animals
- Antibodies, Antinuclear/biosynthesis
- Antibodies, Antinuclear/blood
- Antibodies, Antinuclear/immunology
- Antigen-Antibody Complex/immunology
- Autoimmunity/immunology
- Cells, Cultured
- Complement C4/deficiency
- Complement C4/genetics
- Complement C4/immunology
- Complement C4/metabolism
- Disease Models, Animal
- Enzyme-Linked Immunosorbent Assay
- Female
- Gene Deletion
- Histocytochemistry
- Kidney/immunology
- Kidney/pathology
- Lupus Erythematosus, Systemic/complications
- Lupus Erythematosus, Systemic/immunology
- Lupus Erythematosus, Systemic/pathology
- Lymphocyte Activation/immunology
- Male
- Mice
- Mice, Inbred Strains
- Mice, Knockout
- Receptors, Complement 3b/immunology
- Receptors, Complement 3b/metabolism
- Receptors, Complement 3d/deficiency
- Receptors, Complement 3d/genetics
- Receptors, Complement 3d/immunology
- Receptors, Complement 3d/metabolism
- Spleen/immunology
- Spleen/pathology
- Splenomegaly/complications
- Splenomegaly/immunology
- Splenomegaly/pathology
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Affiliation(s)
- Z Chen
- Department of Immunology, Duke University Medical Center, Durham, North Carolina 27710, USA
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368
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Dean YD, McGreal EP, Akatsu H, Gasque P. Molecular and cellular properties of the rat AA4 antigen, a C-type lectin-like receptor with structural homology to thrombomodulin. J Biol Chem 2000; 275:34382-92. [PMID: 10934210 DOI: 10.1074/jbc.m006229200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The murine fetal stem cell marker AA4 has recently been cloned and is known to be the homolog of the human phagocytic C1q receptor involved in host defense. We herein report the molecular cloning and the cellular expression pattern of the rat AA4 antigen. Modular architecture analysis indicated that the rat AA4 is a member of C-type lectin-like family and, interestingly, displays similar domain composition and organization to thrombomodulin. Northern blot and reverse transcriptase-polymerase chain reaction analyses indicated that rat AA4 was encoded by a single transcript of 7 kilobases expressed constitutively in all tissues. In situ hybridization showed that AA4 was expressed predominantly by pneumocytes and vascular endothelial cells. Using an affinity purified polyclonal antibody raised against a rat AA4-Fc fusion protein, AA4 was identified as a glycosylated protein of 100 kDa expressed by endothelial cells > platelets > NK cells and monocytes (ED1+ cells). The staining was associated to the cell surface and intracytoplasmic vesicles. Conversely, erythrocytes, T and B lymphocytes, neutrophils, and macrophages (ED2+ cells) were consistently negative for AA4. As expected, the macrophage cell line NR8383 expressed weak levels of AA4. Taken together, our results support the idea that AA4/C1qRp is involved in some cell-cell interactions.
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Affiliation(s)
- Y D Dean
- Brain Inflammation and Immunity Group, Medical Biochemistry Department, University of Wales College of Medicine, Cardiff, CF144XN, United Kingdom
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369
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Lentz VM, Manser T. Self-limiting systemic autoimmune disease during reconstitution of T cell-deficient mice with syngeneic T cells: support for a multifaceted role of T cells in the maintenance of peripheral B cell tolerance. Int Immunol 2000; 12:1483-97. [PMID: 11058568 DOI: 10.1093/intimm/12.11.1483] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The T cell compartment can be partially reconstituted in mice with targeted inactivation of the TCR C(beta) and C(delta) genes by injection of mature, syngeneic T cells. Surprisingly, during this reconstitution high titers of IgG anti-nuclear antibodies and symptoms of systemic autoimmune disease develop. However, this autoimmune response is transient and aged, reconstituted mice show no overt signs of disease. The autoantibody response appears to be derived from a pre-existing population of host self-reactive B cells and requires CD40 ligand-mediated co-stimulation from donor cells. Diminution of this response is coincident with a vigorous germinal center reaction and the disappearance of a subpopulation of activated B cells that expresses elevated levels of Fas. Collectively, our data support the idea that T cells play a multifaceted role in the maintenance of peripheral B cell tolerance that includes mediating the activation-induced death of autospecific B cells.
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MESH Headings
- Adoptive Transfer
- Animals
- Autoantibodies/biosynthesis
- Autoantigens/immunology
- Autoimmune Diseases/immunology
- Autoimmune Diseases/pathology
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- Cell Communication/immunology
- Genes, T-Cell Receptor beta/genetics
- Genes, T-Cell Receptor delta/genetics
- Germinal Center/immunology
- Germinal Center/pathology
- Immunoglobulin G/biosynthesis
- Injections, Intravenous
- Lymphocyte Activation/genetics
- Lymphocyte Depletion
- Lymphopenia/immunology
- Lymphopenia/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Receptors, Antigen, T-Cell, alpha-beta/deficiency
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, gamma-delta/deficiency
- Receptors, Antigen, T-Cell, gamma-delta/genetics
- Self Tolerance/genetics
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/transplantation
- T-Lymphocytes/immunology
- T-Lymphocytes/transplantation
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Affiliation(s)
- V M Lentz
- Department of Microbiology and Immunology, Jefferson Medical College, BLSB 708, 233 South 10th Street, Philadelphia, PA 19107, USA
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370
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Sorice M, Circella A, Misasi R, Pittoni V, Garofalo T, Cirelli A, Pavan A, Pontieri GM, Valesini G. Cardiolipin on the surface of apoptotic cells as a possible trigger for antiphospholipids antibodies. Clin Exp Immunol 2000; 122:277-84. [PMID: 11091286 PMCID: PMC1905767 DOI: 10.1046/j.1365-2249.2000.01353.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study provides evidence that cardiolipin (CL) molecules are expressed on the surface of apoptotic cells and are recognized by antiphospholipid antibodies, purified from patients with the antiphospholipid antibody syndrome (APS). CL expression on cell surface was demonstrated by high performance thin layer chromatography analysis of phospholipids from plasma membrane purified fractions and by the positive staining with the CL-specific dye nonyl-acridine orange. This finding was complemented with the observation that aCL IgG purified from patients with APS bind to the surface of apoptotic cells. This staining shows a clustered distribution mostly localized on surface blebs. Interestingly, CL exposure on the cell surface preceded the DNA fragmentation, as shown by cytofluorimetric analysis. These findings demonstrate that exposure of CL molecules on the cell plasma membrane is an early event of the apoptotic cellular program that may represent an in vivo trigger for the generation of aCL.
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Affiliation(s)
- M Sorice
- Dipartimento Medicina Sperimentale e Patologia, Università La Sapienza Roma, Italy
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371
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Abstract
While philosophers seek the meaning of life, cell biologists are becoming ever more interested in the meaning of death. Apoptosis marks unwanted cells with 'eat me' signals that direct recognition, engulfment and degradation by phagocytes. Far from being the end of the story, these clearance events allow scavenger cells to confer meaning upon cell death. But if the phagocytic 'spin doctors' receive or transmit the wrong messages, trouble ensues.
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Affiliation(s)
- J Savill
- University of Edinburgh/Medical Research Council Centre for Inflammation Research, Department of Clinical and Surgical Sciences, Internal Medicine, Royal Infirmary, UK.
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372
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Abstract
Nucleosomes play a central role in the antinuclear antibody response in lupus. Lupus anti-dsDNA and antihistone antibodies directed toward nucleosomes belong together with nucleosome-specific antibodies, to a broad antinucleosome antibody family. Besides anti-dsDNA, nucleosome-specific antibodies have a major role in the pathophysiology of systemic lupus erythematosus (SLE) and emphasize the role of nucleosome-antinucleosome immune complexes. Antinucleosome immunoglobulin G antibodies are a more sensitive marker of SLE than anti-dsDNA, and are almost exclusively found in lupus, scleroderma, and mixed connective tissue diseases. An understanding of the key role of the nucleosome will likely make possible new therapeutic interventions in SLE, such as a tolerance induction to the subnucleosomal particles.
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Affiliation(s)
- Z Amoura
- Service de Médecine Interne, Hôpital Pitié-Salpêtrière, Paris, France.
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373
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Abstract
The target of many antiphospholipid autoantibodies (APA) has been shown to be a complex between anionic phospholipid (PL) and the plasma protein beta 2-glycoprotein I (beta 2-GPI), but the identity of the natural target(s) and/or immunogen for APA in vivo remains undetermined. The anionic PL of cell membranes represent important potential targets and immunogenes for APA. Although anionic PL are normally absent from the extracellular surface of cell membranes, they redistribute from the inner to the outer leaflet during apoptosis. We and others have shown that beta 2-GPI binds selectively to the surface of apoptotic, but not viable, cells, and that the binding of beta 2-GPI to the surface of apoptotic cells generates an epitope recognized by APA from patients with both primary antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE). In this review, we discuss recent findings, which suggest not only that apoptotic cell-bound beta 2-GPI is injected by non-intravenous routes. We also review briefly the potential role of oxidation in generating epitopes responsible for the recognition and induction of APA. Taken together, we believe that the available evidence supports a role for apoptotic cells as far as targets of APA and possible players in the induction of APA.
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Affiliation(s)
- J Rauch
- Division of Rheumatology, Department of Medicine, The Montreal General Hospital Research Institute, McGill University, Montreal, Quebec, H3G 1A4, Canada.
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374
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Pollard KM, Pearson DL, Blüthner M, Tan EM. Proteolytic cleavage of a self-antigen following xenobiotic-induced cell death produces a fragment with novel immunogenic properties. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:2263-70. [PMID: 10925315 DOI: 10.4049/jimmunol.165.4.2263] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The heavy metal mercury elicits a genetically restricted autoantibody response in mice that targets the nucleolar autoantigen fibrillarin. HgCl2-induced cell death of macrophages resulted in the proteolytic cleavage of fibrillarin. A prominent feature of mercury-induced cell death was the generation of a 19-kDa fragment of fibrillarin that was not found following apoptotic or nonapoptotic cell death induced by stimuli other than mercury. Proteolysis of fibrillarin lacking cysteines, and therefore unable to bind mercury, also produced the 19-kDa fragment, suggesting that a mercury-fibrillarin interaction was not necessary for the unique cleavage pattern of this self-Ag. In contrast to immunization with full-length fibrillarin, the 19-kDa fragment produced anti-fibrillarin Abs with some of the properties of the HgCl2-induced anti-fibrillarin response. We propose that cell death following exposure to an autoimmunity-inducing xenobiotic can lead to the generation of novel protein fragments that may serve as sources of antigenic determinants for self-reactive T lymphocytes.
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Affiliation(s)
- K M Pollard
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
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375
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Taylor PR, Carugati A, Fadok VA, Cook HT, Andrews M, Carroll MC, Savill JS, Henson PM, Botto M, Walport MJ. A hierarchical role for classical pathway complement proteins in the clearance of apoptotic cells in vivo. J Exp Med 2000; 192:359-66. [PMID: 10934224 PMCID: PMC2193213 DOI: 10.1084/jem.192.3.359] [Citation(s) in RCA: 513] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2000] [Accepted: 05/23/2000] [Indexed: 12/02/2022] Open
Abstract
The strongest susceptibility genes for the development of systemic lupus erythematosus (SLE) in humans are null mutants of classical pathway complement proteins. There is a hierarchy of disease susceptibility and severity according to the position of the missing protein in the activation pathway, with the severest disease associated with C1q deficiency. Here we demonstrate, using novel in vivo models of apoptotic cell clearance during sterile peritonitis, a similar hierarchical role for classical pathway complement proteins in vivo in the clearance of apoptotic cells by macrophages. Our results constitute the first demonstration of an impairment in the phagocytosis of apoptotic cells by macrophages in vivo in a mammalian system. Apoptotic cells are thought to be a major source of the autoantigens of SLE, and impairment of their removal by complement may explain the link between hereditary complement deficiency and the development of SLE.
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Affiliation(s)
- Philip R. Taylor
- Rheumatology Section, Imperial College School of Medicine, Hammersmith Hospital, London W12 0NN, United Kingdom
| | - Anna Carugati
- Rheumatology Section, Imperial College School of Medicine, Hammersmith Hospital, London W12 0NN, United Kingdom
| | - Valerie A. Fadok
- Department of Pediatrics, National Jewish Medical Research Center, Denver, Colorado 80206
| | - H. Terence Cook
- Department of Histopathology, Imperial College School of Medicine, Hammersmith Hospital, London W12 0NN, United Kingdom
| | - Mark Andrews
- Division of Renal and Inflammatory Disease, University Hospital, Nottingham NG7 2UH, United Kingdom
| | - Michael C. Carroll
- Center for Blood Research, Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02165
| | - John S. Savill
- Centre for Inflammation Research, University of Edinburgh Medical School, Edinburgh EH3 9YW, United Kingdom
| | - Peter M. Henson
- Department of Pediatrics, National Jewish Medical Research Center, Denver, Colorado 80206
| | - Marina Botto
- Rheumatology Section, Imperial College School of Medicine, Hammersmith Hospital, London W12 0NN, United Kingdom
| | - Mark J. Walport
- Rheumatology Section, Imperial College School of Medicine, Hammersmith Hospital, London W12 0NN, United Kingdom
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376
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Abstract
C1q is the first subcomponent of the C1 complex of the classical pathway of complement activation. Several functions have been assigned to C1q, which include antibody-dependent and independent immune functions, and are considered to be mediated by C1q receptors present on the effector cell surface. There remains some uncertainty about the identities of the receptors that mediate C1q functions. Some of the previously described C1q receptor molecules, such as gC1qR and cC1qR, now appear to have less of a role in C1q functions than in functions unrelated to C1q. The problem of identifying receptor proteins with complementary binding sites for C1q has been compounded by the highly charged nature of the different domains in C1q. Although newer candidate receptors like C1qR(p) and CR1 have emerged, full analysis of the C1q-C1q receptor interactions is still at an early stage. In view of the diverse functions that C1q is considered to perform, it has been speculated that several C1q-binding proteins may act in concert, as a C1q receptor complex, to bring about C1q mediated functions. Some major advances have been made in last few years. Experiments with gene targeted homozygous C1q-deficient mice have suggested a role for C1q in modulation of the humoral immune response, and also in protection against development of autoimmunity. The recently described crystal structure of Acrp-30, which is a serum protein secreted from adipocytes, has revealed a new C1q/TNF superfamily of proteins. Although the members of this superfamily may have diverse functions, there may be a common theme in their phylogeny and modular organisation of their distinctive globular domains.
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Affiliation(s)
- U Kishore
- Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, UK
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377
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Yang YS, Yang MC, Wang B, Weissler JC. Autoantigen Ro52 directly interacts with human IgG heavy chain in vivo in mammalian cells. Mol Immunol 2000; 37:591-602. [PMID: 11163395 DOI: 10.1016/s0161-5890(00)00068-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Previously, when we used in vivo yeast two-hybrid and in vitro protein-protein interaction analyses, we demonstrated a direct interaction between autoantigen Ro52 and the human IgG heavy chain. This interaction occurred in the absence of antibody-antigen specific interaction. Here, by employing a novel strategy, we further demonstrated that Ro52 co-localized with IgG in transfected mammalian cells. The co-localization was specific to IgG1 but not IgG3. Co-immunoprecipitating IgG with Ro52 from transfected cell lysates suggested that protein complex containing Ro52 and IgG contributed to the in vivo co-localization. In addition, IgG from normal human serum was shown to bind to the surface of apoptotic keratinocytes and the binding could be competitively blocked by 50-fold excesses of IgG1, not IgG3. With a direct binding study, we also demonstrated that IgG1 could bind to the surface of apoptotic cells while IgG3 bound barely. This binding was not competed by Fcgamma fragments indicating a non-Fcgamma receptor mediated interaction. Finally, in a competition analysis the addition of GST-RFP could reduce the IgG binding to the cell surface. Thus, we suggested that the binding of IgG to the apoptotic keratinocytes might be mediated through the interactions with the surface exposed Ro52. The potential role of forming this protein complex on the apoptotic cells will be discussed.
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Affiliation(s)
- Y S Yang
- Department of Internal Medicine, Pulmonary and Critical Care Division, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9034, USA.
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378
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Rovere P, Sabbadini MG, Fazzini F, Bondanza A, Zimmermann VS, Rugarli C, Manfredi AA. Remnants of suicidal cells fostering systemic autoaggression. Apoptosis in the origin and maintenance of autoimmunity. ARTHRITIS AND RHEUMATISM 2000; 43:1663-72. [PMID: 10943854 DOI: 10.1002/1529-0131(200008)43:8<1663::aid-anr1>3.0.co;2-1] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- P Rovere
- Istituto Scientifico H.S. Rafaele, and Università Vita-Salute San Raffaele, Milan, Italy
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379
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Evans MD, Cooke MS, Akil M, Samanta A, Lunec J. Aberrant processing of oxidative DNA damage in systemic lupus erythematosus. Biochem Biophys Res Commun 2000; 273:894-8. [PMID: 10891343 DOI: 10.1006/bbrc.2000.3078] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Defective DNA damage processing has been reported in systemic lupus erythematosus (SLE). Vitamin C may modulate formation/removal of the oxidative DNA lesion 8-oxo-2'-deoxyguanosine (8-oxodG). Baseline levels of 8-oxodG measured in SLE serum, urine and PBMC DNA did not differ significantly from healthy subjects. In contrast to healthy subjects, no significant decrease in PBMC 8-oxodG or increase in urinary 8-oxodG was noted in vitamin C supplemented SLE patients. A significant, although attenuated, increase in serum 8-oxodG was detected in SLE patients, compared to healthy subjects. These data support putative abnormalities in the repair/processing of 8-oxodG in SLE.
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Affiliation(s)
- M D Evans
- Division of Chemical Pathology, CMHT, University of Leicester, Hodgkin Building, Lancaster Road, Leicester, LE1 9HN, United Kingdom
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380
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Abstract
Systemic autoimmune diseases are characterized by the production of antibodies against a broad range of self-antigens. Recent evidence indicates that the majority of these autoantigens are modified in various ways during cell death. This has led to the hypothesis that the primary immune response in the development of autoimmunity is directed to components of the dying cell. In this article, we summarize data on the modification of autoantigens during cell death and the possible consequences of this for autoimmunity.
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Affiliation(s)
- R J Rodenburg
- Department of Biochemistry, University of Nijmegen, The Netherlands
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381
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Abstract
The increasing use of implanted biomaterial devices has made it evident that no material is biologically inert. As a result of direct contact with elements of the blood circulation, such as during hemodialysis or after left ventricular assist device (LVAD) implantation, significant changes in systemic immunologic and thrombostatic functions occur. The clinical success of LVAD implantation has, nevertheless, been accompanied by complications arising from an aberrant state of monocyte and T-cell activation, leading to heightened susceptibility of circulating CD4 T cells to undergo activation-induced cell death; this results in progressive defects in cellular immunity and an increased risk of serious infection. Because of the increased state of T-cell activation and the selective loss of Th1 cytokine producing CD4 T cells, LVAD recipients also develop B-cell hyperreactivity and dysregulated immunoglobulin syntheses by unopposed production of Th2 cytokines and increased CD40 Ligand-CD40 interactions. LVADs are currently being evaluated as a permanent therapy for end-stage heart failure. Because these immune dysfunctions appear to be related to the effects of excessive biomaterial associated T-cell activation, future efforts will need to be directed at either altering the physical properties of the materials interacting with the host circulation or pharmacological intervention aimed at inhibiting T-cell activation.
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Affiliation(s)
- S Itescu
- Department of Surgery, Columbia-Presbyterian Medical Center, New York, NY 10032, USA
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382
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Sustaining the graft-versus-tumor effect through posttransplant immunization with granulocyte-macrophage colony-stimulating factor (GM-CSF)–producing tumor vaccines. Blood 2000. [DOI: 10.1182/blood.v95.10.3011.010k15_3011_3019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For many cancers, autologous bone marrow transplantation (BMT) achieves a minimal residual disease state, yet relapse rates remain high. Using a syngeneic murine bone marrow transplant model, we demonstrate that vaccination with irradiated granulocyte-macrophage colony-stimulating factor (GM-CSF)–producing autologous tumor cells is effective in the post-BMT period and actually results in a greater tumor-free survival than vaccination in the nontransplant setting. Employing T cells specific for a model tumor-antigen, we find that transplantation of the tumor-bearing host results in a massive expansion and activation of tumor-specific T cells in the early posttransplant period, but this response rapidly declines in association with tumor progression. Immunization with irradiated GM-CSF tumor cells during the period of immune reconstitution results in the sustained amplification and activation of this response that closely correlates with freedom from relapse. These results demonstrate the feasibility of integrating GM-CSF vaccines in the postautologous BMT setting and suggest mechanisms that may contribute to the observed efficacy of immunization during the critical period of immune reconstitution.
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383
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Sustaining the graft-versus-tumor effect through posttransplant immunization with granulocyte-macrophage colony-stimulating factor (GM-CSF)–producing tumor vaccines. Blood 2000. [DOI: 10.1182/blood.v95.10.3011] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
For many cancers, autologous bone marrow transplantation (BMT) achieves a minimal residual disease state, yet relapse rates remain high. Using a syngeneic murine bone marrow transplant model, we demonstrate that vaccination with irradiated granulocyte-macrophage colony-stimulating factor (GM-CSF)–producing autologous tumor cells is effective in the post-BMT period and actually results in a greater tumor-free survival than vaccination in the nontransplant setting. Employing T cells specific for a model tumor-antigen, we find that transplantation of the tumor-bearing host results in a massive expansion and activation of tumor-specific T cells in the early posttransplant period, but this response rapidly declines in association with tumor progression. Immunization with irradiated GM-CSF tumor cells during the period of immune reconstitution results in the sustained amplification and activation of this response that closely correlates with freedom from relapse. These results demonstrate the feasibility of integrating GM-CSF vaccines in the postautologous BMT setting and suggest mechanisms that may contribute to the observed efficacy of immunization during the critical period of immune reconstitution.
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384
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Affiliation(s)
- M P Madaio
- Renal Electrolyte and Hypertension Division, University of Pennsylvania, Philadelphia 19104-6144, USA.
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385
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Andrade F, Casciola-Rosen L, Rosen A. Apoptosis in systemic lupus erythematosus. Clinical implications. Rheum Dis Clin North Am 2000; 26:215-27, v. [PMID: 10768210 DOI: 10.1016/s0889-857x(05)70136-8] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
SLE is a heterogeneous and complex group of disorders of uncertain cause. Recent studies have suggested that abnormalities in the apoptotic cell death process may play an important role in the initiation and propagation of this spectrum of disease by altering the generation and cleavage of antigens, and through abnormalities in immunoregulation. The clustering and concentration of autoantigens in and on the surface blebs of apoptotic cells, modifications of antigen structure during certain forms of apoptotic death, and abnormalities in apoptotic cell clearance in humans with SLE and in certain animal models are reviewed and synthesized into a comprehensive model of systemic autoimmunity.
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Affiliation(s)
- F Andrade
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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386
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Author's reply:. Am J Kidney Dis 2000. [DOI: 10.1016/s0272-6386(00)70278-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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387
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Abstract
Programmed cell death (PCD) can be divided into two distinct but linked sequential processes, killing of the cells and removal of the dead cells, which may be a neighboring cell or a professional phagocyte. Following internalization of the apoptotic cell, the phagocyte typically triggers neither the development of a pro-inflammatory response nor the production of autoantibodies directed against apoptotic self antigens. Since apoptotic cells are characterized by translocation of autoantigens such as nucleosomes to the surface of the cell, we tested the hypothesis that excess or abnormally processed apoptotic cells can generate autoantibodies. We have found that syngeneic apoptotic load can induce transient hypergammaglobulinemia, anti-DNA, anticardiolipin, and glomerular depositions in normal mice. Furthermore, we also found that one of the important mechanisms of uptake of apoptotic cells involves opsonization by the complement system, suggesting that deficient states could lead to aberrant handling of apoptotic cells. Therefore, conditions in which apoptotic cells become immunogenic may explain antigen selection in inflammatory and autoimmune conditions, such as in systemic lupus erythematosus (SLE).
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Affiliation(s)
- D Mevorach
- Laboratory for Cellular and Molecular Immunology, Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Israel.
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388
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Pittoni V, Ravirajan CT, Donohoe S, MacHin SJ, Lydyard PM, Isenberg DA. Human monoclonal anti-phospholipid antibodies selectively bind to membrane phospholipid and beta2-glycoprotein I (beta2-GPI) on apoptotic cells. Clin Exp Immunol 2000; 119:533-43. [PMID: 10691928 PMCID: PMC1905581 DOI: 10.1046/j.1365-2249.2000.01161.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ability of an anti-phospholipid (LJ1) and an anti-beta2-GPI (RSP-57) human MoAb to bind to apoptotic but not viable cells was demonstrated in this study. Both MoAbs were derived from patients with systemic lupus erythematosus and anti-phospholipid antibody syndrome. The parallel analysis of the specificity and affinity of four anti-phospholipid human MoAbs suggests that the binding of LJ1 MoAb to apoptotic cells is a specific property of this MoAb. RSP-57 MoAb recognizes apoptotic cells through beta2-GPI which becomes available for binding after the interaction with negatively charged phospholipids. This observation provides evidence that the binding of human anti-phospholipid antibodies to apoptotic cells occurs in both a beta2-GPI-dependent and independent way and involves a restricted group of epitopes. The finding that LJ1 and RSP-57 MoAbs bind apoptotic cells underlines the property of these MoAbs to act as cell membrane markers of apoptosis. Major pathological implications derive from the observation that LJ1 and RSP-57 MoAbs recognize epitopes expressed on 'early' apoptotic cells. The interference with the in vivo clearance and processing of apoptotic cells is a potential pathogenic mechanism of these antibodies.
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Affiliation(s)
- V Pittoni
- Centre for Rheumatology/Bloomsbury Rheumatology Unit, Department of Medicine and Department of Haematology, University College London, London, UK
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389
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Yrlid U, Wick MJ. Salmonella-induced apoptosis of infected macrophages results in presentation of a bacteria-encoded antigen after uptake by bystander dendritic cells. J Exp Med 2000; 191:613-24. [PMID: 10684853 PMCID: PMC2195841 DOI: 10.1084/jem.191.4.613] [Citation(s) in RCA: 200] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Salmonella typhimurium is a gram-negative bacterium that survives and replicates inside vacuolar compartments of macrophages. Infection of macrophages with S. typhimurium grown under conditions allowing expression of the type III secretion system results in apoptotic death of the infected cells. Here, we show that infection of bone marrow-derived macrophages (MPhi) with wild-type S. typhimurium 14028 results in presentation of epitopes derived from a bacteria-encoded antigen on major histocompatibility complex (MHC) class I and MHC class II molecules after internalization of apoptotic MPhi by bystander dendritic cells (DCs). In contrast, infection of MPhi with the phoP constitutive mutant strain CS022, which does not induce apoptosis in infected MPhi, does not result in presentation of a bacteria-derived antigen by bystander DCs unless the infected MPhi are induced to undergo apoptosis by treatment with lipopolysaccharide and ATP. DCs appear to be unique in their ability to present antigens derived from MPhi induced to undergo apoptosis by Salmonella, as bystander MPhi are not capable of presenting the bacteria-derived antigen despite the fact that they efficiently internalize the apoptotic cells. These data suggest that apoptosis induction by bacterial infection of MPhi may not be a quiescent death that allows the bacteria to escape recognition by the immune system, but rather may contribute to an antimicrobial immune response upon engulfment by bystander DCs.
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Affiliation(s)
- Ulf Yrlid
- From the Department of Cell and Molecular Biology, Section for Immunology, Lund University, S-223 62 Lund, Sweden
| | - Mary Jo Wick
- From the Department of Cell and Molecular Biology, Section for Immunology, Lund University, S-223 62 Lund, Sweden
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390
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Utz PJ, Gensler TJ, Anderson P. Death, autoantigen modifications, and tolerance. ARTHRITIS RESEARCH 2000; 2:101-14. [PMID: 11094420 PMCID: PMC129993 DOI: 10.1186/ar75] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/04/2000] [Revised: 01/17/2000] [Accepted: 01/20/2000] [Indexed: 12/18/2022]
Abstract
Autoantibodies present in the serum of patients with a variety of inflammatory diseases have proven useful as diagnostic markers and as probes with which to elucidate biochemical and signaling pathways. The mechanisms governing the generation of autoantibodies remain elusive, constituting a critical missing link in our understanding of rheumatologic illnesses. Several lines of experimentation in recent years have strongly implicated events surrounding cell death in this process. This review will address the potential role played by death-specific modifications of autoantigens in bypassing tolerance to highly conserved autoantigens, including nucleic acids, lipids, and proteins.
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Affiliation(s)
- P J Utz
- Department of Medicine, Stanford University School of Medicine, Stanford, California 94305, USA.
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391
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Akashi S, Ogata H, Kirikae F, Kirikae T, Kawasaki K, Nishijima M, Shimazu R, Nagai Y, Fukudome K, Kimoto M, Miyake K. Regulatory roles for CD14 and phosphatidylinositol in the signaling via toll-like receptor 4-MD-2. Biochem Biophys Res Commun 2000; 268:172-7. [PMID: 10652232 DOI: 10.1006/bbrc.2000.2089] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The complex consisting of Toll-like receptor 4 (TLR4) and associated MD-2 signals the presence of lipopolysaccharide (LPS) when it is expressed in cell lines. We here show that normal human mononuclear cells express TLR4 and signal LPS via TLR4. CD14 is a molecule that binds to LPS and facilitates its signaling. Little is known, however, about the relationship of CD14 with TLR4-MD-2. We show that CD14 helps TLR4-MD-2 to sense and signal the presence of LPS. CD14 has also been implicated in recognition of apoptotic cells, which leads to phagocytosis without activation. Membrane phospholipids such as phosphatidylserine (PS) or phosphatidylinositol (PtdIns) are thought to serve as the ligands for CD14 in apoptotic cells. We find that PtdIns acts as an LPS antagonist in the signaling via TLR4-MD-2. TLR4-MD-2 seems to discriminate LPS from phospholipids. The signaling via TLR4-MD-2 is thus regulated by CD14 and phospholipid such as PtdIns.
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Affiliation(s)
- S Akashi
- Department of Immunology, Saga Medical School, Saga, Nabeshima, Japan
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392
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Martelli AM, Tazzari PL, Bortul R, Riccio M, Tabellini G, Santi S, Frabetti F, Musiani D, Bareggi R, Conte R. Nuclear matrix protein is released from apoptotic white cells during cold (1-6 degrees C) storage of concentrated red cell units and might induce antibody response in multiply transfused patients. Transfusion 2000; 40:169-77. [PMID: 10686000 DOI: 10.1046/j.1537-2995.2000.40020169.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND A previous study showed that white cells in blood units undergo apoptosis during storage. STUDY DESIGN AND METHODS The present study attempts to show the release of nuclear matrix protein (NMP) in the supernatants of red cell units and to determine whether antibodies against nuclear components may be present in multiply transfused patients; the methods employed were enzyme-linked immunosorbent assay, flow cytometry, microscopy, immunoblotting, immunofluorescence, and confocal laser-scanning microscopy. RESULTS NMP is released from white cells in the supernatant of packed red cell units upon cold storage (1-6 degrees C). The concentration of NMP correlates well with the degree of apoptosis, as analyzed by flow cytometry, nuclear dye staining, and DNA gel electrophoresis. Immunofluorescence also shows that white cells undergoing apoptosis (pre-G(1) peak, as seen by propidium iodide staining and flow cytometry) have an NMP content lower than control cells, which confirms an actual release of NMP. Moreover, immunoblotting analysis and immunofluorescent staining showed that, in 4 of 38 multiply transfused patients, autoantibodies against NMPs were present without any clinical or laboratory sign of autoimmune disease. One of the sera, recognizing a 64-kDa NMP, immunostained nuclear dots that were identified as coiled bodies because of their colocalization with p 80 coilin. CONCLUSION NMP is released in the supernatant of red cell units. The results obtained from patients suggest that nuclear proteins released during apoptosis, once transfused, may induce an immune response in multiply transfused patients.
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Affiliation(s)
- A M Martelli
- Department of Normal Human Morphology, University of Trieste, Trieste, Italy
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393
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Abstract
Until very recently, the function of CD14 was thought to be limited to innate immune responses to bacterial and other microbial structures. It is now known that macrophage CD14 serves an additional unexpected function, namely as a receptor involved in the recognition and phagocytosis of cells undergoing apoptosis. In stark contrast to its role in eliciting pro-inflammatory responses following binding of microbial ligands, macrophage CD14 mediates clearance of apoptotic cells without inciting inflammation. Increasing interest in the profoundly important final stage of apoptosis - the engulfment process - together with significant advances in knowledge of the immunological consequences of apoptotic-cell clearance and of the means by which signal transduction may be achieved following CD14-ligand binding have begun to produce a clearer picture of the role of CD14 in the immune system.
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Affiliation(s)
- C D Gregory
- D Floor, Institute of Cell Signalling and School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
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394
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Navratil JS, Ahearn JM. Apoptosis and autoimmunity: complement deficiency and systemic lupus erythematosus revisited. Curr Rheumatol Rep 2000; 2:32-8. [PMID: 11123037 DOI: 10.1007/s11926-996-0066-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Apoptosis may have a dual role in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus. First, this process may be integral in the clonal deletion of self-reactive lymphocytes and maintenance of peripheral tolerance. Second, apoptosis generates altered self-antigens with the potential for breaking self-tolerance. This review will discuss these two aspects of apoptosis and autoimmunity, and explore the potential role of the classical complement pathway in this context.
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Affiliation(s)
- J S Navratil
- University of Pittsburgh School of Medicine, University of Pittsburgh Arthritis Institute, E1152 Biomedical Science Tower, 200 South Lothrop Street, Pittsburgh, PA 15261, USA
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395
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Pickering MC, Walport MJ. Links between complement abnormalities and systemic lupus erythematosus. Rheumatology (Oxford) 2000; 39:133-41. [PMID: 10725062 DOI: 10.1093/rheumatology/39.2.133] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Affiliation(s)
- M C Pickering
- Rheumatology Section, Department of Medicine, Imperial College School of Medicine, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
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396
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Boes M, Schmidt T, Linkemann K, Beaudette BC, Marshak-Rothstein A, Chen J. Accelerated development of IgG autoantibodies and autoimmune disease in the absence of secreted IgM. Proc Natl Acad Sci U S A 2000; 97:1184-9. [PMID: 10655505 PMCID: PMC15562 DOI: 10.1073/pnas.97.3.1184] [Citation(s) in RCA: 288] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Individuals with systemic lupus erythematosus and rheumatoid arthritis are characterized by the presence of high levels of circulating IgM and IgG autoantibodies. Although IgG autoantibodies often are pathogenic, the role of IgM autoantibodies in autoimmune disease is not clear. Using mice that are unable to secrete IgM but are able to express surface IgM and IgD and to secrete other classes of immunoglobulins, we examined the effect of the absence of secreted IgM in the development of IgG autoantibodies and autoimmune disease in lupus-prone lymphoproliferative (lpr) mice. Compared with regular lpr mice, lpr mice that lack secreted IgM developed elevated levels of IgG autoantibodies to double-stranded DNA and histones and had more abundant deposits of immune complexes in the glomeruli; they also suffered more severe glomerulonephritis and succumbed to the disease at an earlier age. Similarly, the absence of secreted IgM also resulted in an accelerated development of IgG autoantibodies in normal mice. These findings suggest that secreted IgM, including IgM autoantibodies produced naturally or as part of an autoimmune response, may lessen the severity of autoimmune pathology associated with IgG autoantibodies.
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Affiliation(s)
- M Boes
- Center for Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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397
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Affiliation(s)
- T Grodzicky
- Department of Medicine, Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York 10021, USA
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398
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Abstract
It is speculated that presentation of self-peptides to autoreactive T cells normally results in T cell tolerance. In autoimmune conditions, breakdown in the tolerization process results in activation of self-reactive T cells and an immune attack on host tissues. Our understanding of the immune cells and signaling pathways that contribute to this breakdown in T cell tolerization mechanisms is beginning to be deciphered. In particular, the elucidation of the mechanisms that contribute to the release of host antigen, the identification of the antigen-presenting cells that present the host peptides to self-reactive T cells and the role of members of the tumor necrosis factor receptor/ligand families that contribute to inappropriate activation of self-reactive T cells is advancing. The accumulating data from these studies will hopefully provide new ideas for combating autoimmunity.
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Affiliation(s)
- E A Green
- Section of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
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399
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Abstract
Professional antigen-presenting cells (pAPC) can process and present exogenous antigens on major histocompatibility complex class I (MHC-I) molecules. This unusual pathway for antigen presentation may represent a physiologically important step in the course of priming and tolerance induction of CD8+ T cells. In addition, it may play an important role in immunological surveillance for pathogens that survive in vacuolar compartments in APC. The goal of the present review is to discuss recent studies on the processing of bacterial-derived antigens for presentation on MHC-I molecules. The antigen presentation emphasized will include bacteria that remain confined in vacuolar compartments. This is in contrast to antigens derived from bacteria that have intrinsic properties allowing translocation across membranes and access into the classical MHC-I presentation pathway. In particular, presentation of bacterial antigens by dendritic cells (DC) will be emphasized, and MHC-I presentation of antigens derived from apoptotic cells, particularly cells induced to undergo apoptosis by microbial infection, will be presented. Finally, some special aspects of the interaction between bacteria and DC will be discussed as it relates to DC maturation, antigen presentation and T-cell stimulation.
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Affiliation(s)
- M J Wick
- Department of Cell and Molecular Biology, Lund University, Sweden.
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400
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Petrovas C, Vlachoyiannopoulos PG, Kordossis T, Moutsopoulos HM. Anti-phospholipid antibodies in HIV infection and SLE with or without anti-phospholipid syndrome: comparisons of phospholipid specificity, avidity and reactivity with beta2-GPI. J Autoimmun 1999; 13:347-55. [PMID: 10550222 DOI: 10.1006/jaut.1999.0324] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increased prevalence of anti-phospholipid antibodies (aPL) and increased levels of lipid peroxidation have been described in patients with HIV infection. To assess the binding specificity and avidity of aPL antibodies in HIV infection, sera from 44 HIV-1 infected patients were evaluated for antibodies to cardiolipin (aCL), phosphatidyl serine (aPS), phosphatidyl inositol (aPI) and phosphatidyl choline (aPC) using enzyme linked immunosorbent assay (ELISA) methods. Sera from 30 patients with systemic lupus erythematosus (SLE), but without features of anti-phospholipid syndrome (APS) (SLE/non APS), six with SLE and secondary APS, (SLE/APS) and 11 with primary APS (PAPS) were also evaluated as controls. The resistance of the aPL antibody binding to dissociating agents was evaluated by treating the ELISA wells, after serum incubation with 2 M urea or 0.6 M NaCl for 10 min. An anti-beta2-glycoprotein-I (beta2-GPI) ELISA was used to assess serum reactivity against beta2-GPI, a plasma protein considered as the true antigen of aCL antibodies occurring in APS and SLE patients. The prevalence of aCL, aPS, aPI and aPC antibodies in HIV-1 infection was 36%, 56%, 34% and 43% respectively, which was comparable to that found in SLE/APS and PAPS patients and significantly higher than that observed in SLE/non-APS patients. Anti-beta2-GPI antibodies occurred in 5% of HIV-1 infected vs. 17% in SLE/non-APS (P=0.11), 50% in SLE/APS (P=0.009) and 70% in PAPS patients (P=0.0014). A significant decrease of aPL binding after urea and NaCl treatment was observed in the sera of HIV-1-infected, compared to that of APS patients, indicating that aPL antibodies from HIV-1 infected individuals have low resistance to dissociating agents. In conclusion, aPL antibodies (1) occur in HIV-1 infection; (2) tend to recognize various phospholipids but not beta2-GPI; and (3) are of low resistance to dissociating agents-a finding probably reflecting low antibody avidity. Finally, these, like the autoimmune-type aCL antibodies, tend to recognize the oxidized CL-a finding probably indicating autoantibody generation as a result of neoepitope formation by oxidized PLs.
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Affiliation(s)
- C Petrovas
- Department of Pathophysiology, Medical School, National University of Athens, Athens, Greece
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