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Zimmerman LM, Clairardin SG, Paitz RT, Hicke JW, LaMagdeleine KA, Vogel LA, Bowden RM. Humoral immune responses are maintained with age in a long-lived ectotherm, the red-eared slider turtle. ACTA ACUST UNITED AC 2012; 216:633-40. [PMID: 23077164 DOI: 10.1242/jeb.078832] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Aging is typically associated with a decrease in immune function. However, aging does not affect each branch of the immune system equally. Because of these varying effects of age on immune responses, aging could affect taxa differently based on how the particular taxon employs its resources towards different components of immune defense. An example of this is found in the humoral immune system. Specific responses tend to decrease with age while non-specific, natural antibody responses increase with age. Compared with mammals, reptiles of all ages have a slower and less robust humoral immune system. Therefore, they may invest more in non-specific responses and thus avoid the negative consequences of age on the immune system. We examined how the humoral immune system of reptiles is affected by aging and investigated the roles of non-specific, natural antibody responses and specific responses by examining several characteristics of antibodies against lipopolysaccharide (LPS) in the red-eared slider turtle. We found very little evidence of immunosenescence in the humoral immune system of the red-eared slider turtle, Trachemys scripta, which supports the idea that non-specific, natural antibody responses are an important line of defense in reptiles. Overall, this demonstrates that a taxon's immune strategy can influence how the immune system is affected by age.
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Affiliation(s)
- Laura M Zimmerman
- School of Biological Sciences, Illinois State University, Normal, IL 61790, USA.
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152
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Doria A, Gatto M. Nephritogenic-antinephritogenic antibody network in lupus glomerulonephritis. Lupus 2012; 21:1492-6. [PMID: 23042821 DOI: 10.1177/0961203312462267] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Lupus glomerulonephritis (LGN) is one of the most threatening manifestations of systemic lupus erythematosus (SLE) and a major predictor of poor prognosis. The mechanisms leading to kidney inflammation are not completely clear; however, autoantibodies seem to play a pivotal role. Apoptosis dysregulation in SLE is likely to trigger generation of autoantibodies, the released nucleosomes being the driving autoantigen for further epitope amplification and selection of DNA or nucleosome-specific B cells. Growing evidence supports a multistep path to LGN involving initial autoantibody binding to chromatin fragments in the mesangial matrix, where they can induce mesangial inflammation leading to a shut-down of the renal DNase gene, generation and deposition of secondary necrotic chromatin on the glomerular basement membrane favouring antibody binding, complement activation and development of membrano-proliferative glomerular lesions. Anti-DNA IgG antibodies display the major pathogenetic potential in LGN initiation; however, other isotypes (IgA or IgE) as well as autoantibodies targeting other molecules (e.g. anti-C1q, anti-C reactive protein) can perpetuate renal injury. Conversely, protective autoantibodies are also likely in SLE which can contain renal damage targeting either DNA (i.e. IgM anti-DNA) or other molecules (e.g. pentraxin 3). Thus, lupus nephritogenic-antinephritogenic antibodies orchestrate the balance between harm and defence of renal tissue.
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Affiliation(s)
- A Doria
- Division of Rheumatology, Department of Medicine, University of Padova, Italy
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153
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Critical role of the IgM Fc receptor in IgM homeostasis, B-cell survival, and humoral immune responses. Proc Natl Acad Sci U S A 2012; 109:E2699-706. [PMID: 22988094 DOI: 10.1073/pnas.1210706109] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
IgM antibodies have been known for decades to enhance humoral immune responses in an antigen-specific fashion. This enhancement has been thought to be dependent on complement activation by IgM-antigen complexes; however, recent genetic studies render this mechanism unlikely. Here, we describe a likely alternative explanation; mice lacking the recently identified Fc receptor for IgM (FcμR) on B cells produced significantly less antibody to protein antigen during both primary and memory responses. This immune deficiency was accompanied by impaired germinal center formation and decreased plasma and memory B-cell generation. FcμR did not affect steady-state B-cell survival but specifically enhanced the survival and proliferation induced by B-cell receptor cross-linking. Moreover, FcμR-deficient mice produced far more autoantibodies than control mice as they aged, suggesting that FcμR is also required for maintaining tolerance to self-antigens. Our results thus define a unique pathway mediated by the FcμR for regulating immunity and tolerance and suggest that IgM antibodies promote humoral immune responses to foreign antigen yet suppress autoantibody production through at least two pathways: complement activation and FcμR.
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154
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Altered Ig levels and antibody responses in mice deficient for the Fc receptor for IgM (FcμR). Proc Natl Acad Sci U S A 2012; 109:15882-7. [PMID: 22984178 DOI: 10.1073/pnas.1206567109] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cell surface Fc receptor for IgM antibody (FcμR) is the most recently identified member among FcRs. We determined the cellular distribution of mouse FcμR and the functional consequences of Fcmr disruption. Surface FcμR expression was restricted to B-lineage cells, from immature B to plasma cells, except for a transient down-modulation during germinal center reactions. Fcmr ablation had no significant effect on overall B- and T-cell development, but led to a reduction of marginal zone B cells and an increase in splenic B1 B cells. Preimmune serum IgM in mutant mice was significantly elevated as were natural autoantibodies. When immunized with live attenuated pneumococci, mutant mice mounted robust antibody responses against phosphorylcholine, but not protein, determinants compared with wild-type mice. By contrast, upon immunization with a hapten-carrier conjugate, nitrophenyl-coupled chicken γ-globulin (NP-CGG), the mutant mice had a diminished primary IgG1 response to both NP and CGG. These findings suggest that FcμR has an important role in IgM homeostasis and regulation of humoral immune responses.
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155
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Abstract
Systemic lupus erythematosus (SLE) patients with discoid lupus erythematosus (DLE) were reported to have milder disease. To test this observation, we used sandwich arrays containing 98 autoantigens to compare autoantibody profiles of SLE subjects without DLE (DLE-SLE+) (N=9), SLE subjects with DLE (DLE+SLE+) (N=10), DLE subjects without SLE (DLE+SLE-) (N=11), and healthy controls (N=11). We validated differentially expressed autoantibodies using immunoassays in DLE-SLE+ (N=18), DLE+SLE+ (N=17), DLE+SLE- (N=23), and healthy subjects (N=22). Arrays showed 15 IgG autoantibodies (10 against nuclear antigens) and 4 IgM autoantibodies that were differentially expressed (q-value<0.05). DLE-SLE+ subjects had higher IgG autoantibodies against double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), double-stranded RNA (dsRNA), histone H2A and H2B, and SS-A (52 kDa) compared with all other groups including DLE+SLE+ subjects (P<0.05). Immunoassays measuring anti-dsDNA, -ssDNA, and -SS-A (52 kDa) IgG autoantibodies showed similar trends (P<0.05). Healthy and DLE+SLE- subjects expressed higher IgM autoantibodies against alpha beta crystallin, lipopolysaccharide, heat-shock cognate 70, and desmoglein-3 compared with DLE+SLE+ and DLE-SLE+ subjects. IgG:IgM ratios of autoantibodies against nuclear antigens progressively rose from healthy to DLE-SLE+ subjects. In conclusion, lower IgG autoantibodies against nuclear antigens in DLE+SLE+ versus DLE-SLE+ subjects suggest that DLE indicates lower disease severity. Higher IgM autoantibodies against selected antigens in healthy and DLE+SLE- subjects may be nonpathogenic.
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156
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Jiang C, Zhao ML, Waters KM, Diaz M. Activation-induced deaminase contributes to the antibody-independent role of B cells in the development of autoimmunity. Autoimmunity 2012; 45:440-8. [PMID: 22559231 DOI: 10.3109/08916934.2012.682668] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
B cells contribute to autoimmunity both as secretors of pathogenic antibodies and through the activation of autoreactive T cells. B cells and antibodies acquire higher affinity to self-antigen through a process known as immunoglobulin hypermutation or SHM. The contribution of SHM to pathogenic antibody development in lupus has been established in various autoimmune mouse models and by examining antibodies from patients. However, its role in the antibody-independent contribution of B cells to autoimmunity has not been examined. Herein, we generate lupus-prone MRL/lpr mice with a limited IgM-only B cell repertoire, no secreted antibodies and no SHM. This enabled us to isolate the role of somatic hypermutation in B cell-mediated autoimmunity. We found that SHM-deficiency correlated with a reduction in autoreactive B cells, a decrease in T cell activation and a decrease in kidney lymphocytic infiltration. These data establish AID as an important contributor to the antibody-independent role of B cells in autoimmunity.
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Affiliation(s)
- Chuancang Jiang
- Somatic Hypermutation Group, Laboratory of Molecular Genetics, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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157
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Jones DD, DeIulio GA, Winslow GM. Antigen-driven induction of polyreactive IgM during intracellular bacterial infection. THE JOURNAL OF IMMUNOLOGY 2012; 189:1440-7. [PMID: 22730531 DOI: 10.4049/jimmunol.1200878] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Polyreactivity is well known as a property of natural IgM produced by B-1 cells. We demonstrate that polyreactive IgM is also generated during infection of mice with Ehrlichia muris, a tick-borne intracellular bacterial pathogen. The polyreactive IgM bound self and foreign Ags, including single-stranded and double-stranded DNA, insulin, thyroglobulin, LPS, influenza virus, and Borrelia burgdorferi. Production of polyreactive IgM during infection was Ag driven, not due to polyclonal B cell activation, as the majority of polyreactive IgM recognized ehrlichial Ag(s), including an immunodominant outer membrane protein. Monoclonal polyreactive IgM derived from T cell-independent spleen plasmablasts, which was germline-encoded, also bound cytoplasmic and nuclear Ags in HEp-2 cells. Polyreactive IgM protected immunocompromised mice against lethal bacterial challenge infection. Serum from human ehrlichiosis patients also contained polyreactive and self-reactive IgM. We propose that polyreactivity increases IgM efficacy during infection but may also exacerbate or mollify the response to foreign and self Ags.
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Affiliation(s)
- Derek D Jones
- Department of Biomedical Sciences, University at Albany, Albany, NY 12201, USA
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158
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Kaveri SV, Silverman GJ, Bayry J. Natural IgM in immune equilibrium and harnessing their therapeutic potential. THE JOURNAL OF IMMUNOLOGY 2012; 188:939-45. [PMID: 22262757 DOI: 10.4049/jimmunol.1102107] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Natural IgM Abs are the constitutively secreted products of B1 cells (CD5(+) in mice and CD20(+)CD27(+)CD43(+)CD70(-) in humans) that have important and diverse roles in health and disease. Whereas the role of natural IgM as the first line of defense for protection against invading microbes has been extensively investigated, more recent reports have highlighted their potential roles in the maintenance of tissue homeostasis via clearance of apoptotic and altered cells through complement-dependent mechanisms, inhibition of inflammation, removal of misfolded proteins, and regulation of pathogenic autoreactive IgG Abs and autoantibody-producing B cells. These observations have provided the theoretical underpinnings for efforts that currently seek to harness the untapped therapeutic potential of natural IgM either by boosting in vivo natural IgM production or via therapeutic infusions of monoclonal and polyclonal IgM preparations.
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159
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Duarte-Rey C, Bogdanos DP, Leung PS, Anaya JM, Gershwin ME. IgM predominance in autoimmune disease: Genetics and gender. Autoimmun Rev 2012; 11:A404-12. [DOI: 10.1016/j.autrev.2011.12.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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160
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Grönwall C, Vas J, Silverman GJ. Protective Roles of Natural IgM Antibodies. Front Immunol 2012; 3:66. [PMID: 22566947 PMCID: PMC3341951 DOI: 10.3389/fimmu.2012.00066] [Citation(s) in RCA: 241] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 03/16/2012] [Indexed: 12/16/2022] Open
Abstract
Antibodies are a vital part of the armamentarium of the adaptive immune system for the fine-tuning of the recognition and response to foreign threats. However, in health there are some types of antibodies that instead recognize self-antigens and these contribute to the enhancement of primitive innate functions. This repertoire of natural IgM antibodies is postulated to have been selected during immune evolution for their contributions to critical immunoregulatory and housekeeping properties. The clearance of dying cells is one of the most essential responsibilities of the immune system, which is required to prevent uncontrolled inflammation and autoimmunity. In the murine immune system, natural IgM antibodies that recognize apoptotic cells have been shown to enhance the phagocytic clearance of dead and dying cells and to suppress innate immune signaling pathways. In the mouse, natural IgM are often the products of B-1 cell clones that arise during immune development without an absolute requirement for exogenous antigenic stimulation. In patients with systemic lupus erythematosus, IgM autoantibodies, which bind to neo-epitopes on apoptotic cells, have been demonstrated to be present at significantly higher levels in patients with lower disease activity and with less severe organ damage. While certain specificities of IgM autoantibodies correlate with protection from lupus renal disease, others may convey protective properties from lupus-associated atherosclerotic cardiovascular disease. New and unexpected insights into the functional roles of IgM antibodies are still emerging, especially regarding the functions of natural antibodies. Herein, we review recent progress in our understanding of the potential roles of natural IgM autoantibodies in the regulation of immune homeostasis and for protection from autoimmune and inflammatory diseases.
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161
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Mannoor K, Matejuk A, Xu Y, Beardall M, Chen C. Expression of Natural Autoantibodies in MRL-lpr Mice Protects from Lupus Nephritis and Improves Survival. THE JOURNAL OF IMMUNOLOGY 2012; 188:3628-38. [DOI: 10.4049/jimmunol.1102859] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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162
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Greenspan NS, Lu MA, Shipley JW, Ding X, Li Q, Sultana D, Kollaros M, Schreiber JR, Fu P, Putterman C, Emancipator SN. IgG3 deficiency extends lifespan and attenuates progression of glomerulonephritis in MRL/lpr mice. Biol Direct 2012; 7:3. [PMID: 22248284 PMCID: PMC3293080 DOI: 10.1186/1745-6150-7-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 01/16/2012] [Indexed: 12/31/2022] Open
Abstract
Background Antibodies of the IgG3 subclass have been implicated in the pathogenesis of the spontaneous glomerulonephritis observed in mice of the MRL/MpJ-Tnfrsf6lpr (MRL/lpr) inbred strain which have been widely studied as a model of systemic lupus erythematosus We have produced IgG3-deficient (-/-) mice with the MRL/lpr genetic background to determine whether IgG3 antibodies are necessary for or at least contributory to MRL/lpr-associated nephritis. Results The gamma3 genotype (+/+ vs. +/- vs. -/-) did not appear to significantly affect serum titers of IgG auto-antibodies specific for double-stranded DNA (dsDNA) or α-actinin. However, while substantial serum titers of IgG3 auto-antibodies specific for double-stranded DNA (dsDNA) or α-actinin were seen in gamma3 +/+ mice, somewhat lower serum titers of these IgG3 auto-antibodies were found in gamma3 +/- mice, and gamma3 -/- mice exhibited baseline concentrations of these auto-antibodies. Analysis of immunoglobulins eluted from snap-frozen kidneys obtained from mice of all three gamma3 genotypes at ~18 weeks of age revealed much higher quantities of IgG in the kidneys from gamma3 +/+ than gamma3 -/- mice, and most IgG eluted from +/+ mice was IgG3. The serum creatinine levels in gamma3 +/+ mice substantially exceeded those of age-matched gamma3 -/- mice after ~21 weeks of age. Histopathological examination of kidneys from mice sacrificed at pre-determined ages also revealed more extensive glomerulosclerosis in gamma3 +/+ or +/- mice than in -/- mice beginning at 21 weeks of age. Survival analysis for IgG3-deficient and IgG3-producing MRL/lpr mice revealed that gamma3 -/- mice lived significantly longer (p = 0.0006) than either gamma3 +/- or +/+ mice. Spontaneous death appeared to be due to irreversible renal failure, because > 85% of glomeruli in kidneys from mice that died spontaneously were obliterated by glomerulosclerosis. Conclusions The available evidence suggests that IgG3 deficiency partially protects MRL/lpr mice against glomerulonephritis-associated morbidity and mortality by slowing or arresting the progression to glomerulosclerosis. Reviewers This article was reviewed by Pushpa Pandiyan, Irun Cohen, and Etienne Joly.
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Affiliation(s)
- Neil S Greenspan
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4943, USA.
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163
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Abstract
The role of B cells in autoimmune diseases involves different cellular functions, including the well-established secretion of autoantibodies, autoantigen presentation and ensuing reciprocal interactions with T cells, secretion of inflammatory cytokines, and the generation of ectopic germinal centers. Through these mechanisms B cells are involved both in autoimmune diseases that are traditionally viewed as antibody mediated and also in autoimmune diseases that are commonly classified as T cell mediated. This new understanding of the role of B cells opened up novel therapeutic options for the treatment of autoimmune diseases. This paper includes an overview of the different functions of B cells in autoimmunity; the involvement of B cells in systemic lupus erythematosus, rheumatoid arthritis, and type 1 diabetes; and current B-cell-based therapeutic treatments. We conclude with a discussion of novel therapies aimed at the selective targeting of pathogenic B cells.
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Affiliation(s)
- Christiane S. Hampe
- Department of Medicine, University of Washington, SLU-276, 850 Republican, Seattle, WA 98109, USA
- *Christiane S. Hampe:
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164
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Binder CJ. Naturally occurring IgM antibodies to oxidation-specific epitopes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 750:2-13. [PMID: 22903662 DOI: 10.1007/978-1-4614-3461-0_1] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Naturally occurring antibodies (NAbs) have specificity for both microbial and self antigens, which allows them to act in the first line defense against invading pathogens, as well as in tissue homeostasis by mediating the clearance of cellular debris. This latter recognition of self by NAbs was often thought to reflect the polyreactivity of low affinity antibodies. The finding that oxidation-specific epitopes are dominant targets of naturally occurring IgM antibodies shed light on this and provided novel insights into the understanding of the house keeping functions of NAbs. Oxidation-specific epitopes represent stress-induced or altered self structures that are generated as a consequence of lipidperoxidation during many physiological and pathological situations. Importantly, the same structures have been found in the membranes of dying cells. Only oxidized lipids and dying cells-but not native membrane lipids or viable cells-are recognized by this set of NAbs. Thus, oxidation-specific epitopes represent ideal marks that identify biological waste for its clearance and the neutralization of its pro-inflammatory properties. Furthermore, this binding property of NAbs has also important implications for various chronic inflammatory diseases, including atherosclerosis.
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Affiliation(s)
- Christoph J Binder
- Department of Laboratory Medicine, Medical University of Vienna, Austria.
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165
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Abstract
Mouse models of lupus have for many years provided accessible and reliable research systems for the pathogenesis and therapy of systemic autoimmune disease, spanning a spectrum of inbred strains that develop spontaneous disease to experimentally induced, sometimes genetically manipulated animals. Nearly all the models share in common the development of glomerulonephritis and autoantibodies, including antinuclear and DNA specificities, the most common endpoints examined in experimental studies, but exhibit specific differences in the incidence of other end-organ manifestations such as hemolytic anemia, arthritis, dermatitis, and vasculitis. This chapter contrasts the clinical characteristics of these various models, providing an outline for their use and analysis.
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Affiliation(s)
- Stanford L Peng
- Rheumatology Clinical Research Unit, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA.
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166
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Choi YS, Dieter JA, Rothaeusler K, Luo Z, Baumgarth N. B-1 cells in the bone marrow are a significant source of natural IgM. Eur J Immunol 2011; 42:120-9. [PMID: 22009734 DOI: 10.1002/eji.201141890] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 09/01/2011] [Accepted: 10/13/2011] [Indexed: 01/20/2023]
Abstract
Natural IgM antibodies secreted in the absence of antigenic challenge are important contributors to antimicrobial immunity and tissue homeostasis. Early studies identified BM and, to a lesser extent the spleen, as main tissue sources of this spontaneously secreted IgM. However, the responsible B-cell subset has never been identified. Using multicolor flow cytometry, cell sorting and chimeric mice in which B-1 and B-2 cells and their secreted antibodies are distinguished by their Ig-allotype, we unequivocally identify the natural IgM-secreting cells in spleen and, for the first time, in the BM as IgM(+) IgD(lo/-) CD19(hi) CD43(+) CD5(+/-) B-1 cells. The newly identified population of BM B-1 cells shows many of the phenotypic characteristics of splenic B-1 cells but is distinct from B-1 cells in the peritoneal cavity, which generate at best very small amounts of IgM. Antibody-secreting spleen and BM B-1 cells are distinct also from terminally differentiated plasma cells generated from antigen-induced conventional B cells, as they express high levels of surface IgM and CD19 and lack expression of CD138. Overall, these data identify populations of non-terminally differentiated B-1 cells in spleen and BM as the most significant producers of natural IgM.
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Affiliation(s)
- Youn Soo Choi
- The Graduate Group in Immunology, University of California, Davis, Davis, CA 95616, USA
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167
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Aachoui Y, Ghosh SK. Immune enhancement by novel vaccine adjuvants in autoimmune-prone NZB/W F1 mice: relative efficacy and safety. BMC Immunol 2011; 12:61. [PMID: 22024358 PMCID: PMC3214834 DOI: 10.1186/1471-2172-12-61] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 10/24/2011] [Indexed: 01/09/2023] Open
Abstract
Background Vaccines have profoundly impacted global health although concerns persist about their potential role in autoimmune or other adverse reactions. To address these concerns, vaccine components like immunogens and adjuvants require critical evaluation not only in healthy subjects but also in those genetically averse to vaccine constituents. Evaluation in autoimmune-prone animal models of adjuvants is therefore important in vaccine development. The objective here was to assess the effectiveness of experimental adjuvants: two phytol-derived immunostimulants PHIS-01 (phytanol) and PHIS-03 (phytanyl mannose), and a new commercial adjuvant from porcine small intestinal submucosa (SIS-H), relative to a standard adjuvant alum. Phytol derivatives are hydrophobic, oil-in water diterpenoids, while alum is hydrophilic, and SIS is essentially a biodegradable and collagenous protein cocktail derived from extracellular matrices. Results We studied phthalate -specific and cross-reactive anti-DNA antibody responses, and parameters associated with the onset of autoimmune disorders. We determined antibody isotype and cytokine/chemokine milieu induced by the above experimental adjuvants relative to alum. Our results indicated that the phytol-derived adjuvant PHIS-01 exceeded alum in enhancing anti-phthalate antibody without much cross reactivity with ds-DNA. Relatively, SIS and PHIS-03 proved less robust, but they were also less inflammatory. Interestingly, these adjuvants facilitated isotype switching of anti-hapten, but not of anti-DNA response. The current study reaffirms our earlier reports on adjuvanticity of phytol compounds and SIS-H in non autoimmune-prone BALB/c and C57BL/6 mice. These adjuvants are as effective as alum also in autoimmune-prone NZB/WF1 mice, and they have little deleterious effects. Conclusion Although all adjuvants tested impacted cytokine/chemokine milieu in favor of Th1/Th2 balance, the phytol compounds fared better in reducing the onset of autoimmune syndromes. However, SIS is least inflammatory among the adjuvants evaluated.
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Affiliation(s)
- Youssef Aachoui
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA
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168
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Pathak S, Mohan C. Cellular and molecular pathogenesis of systemic lupus erythematosus: lessons from animal models. Arthritis Res Ther 2011; 13:241. [PMID: 21989039 PMCID: PMC3308079 DOI: 10.1186/ar3465] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Systemic lupus erythematosus (SLE) is a complex disease characterized by the appearance of autoantibodies against nuclear antigens and the involvement of multiple organ systems, including the kidneys. The precise immunological events that trigger the onset of clinical manifestations of SLE are not yet well understood. However, research using various mouse strains of spontaneous and inducible lupus in the last two decades has provided insights into the role of the immune system in the pathogenesis of this disease. According to our present understanding, the immunological defects resulting in the development of SLE can be categorized into two phases: (a) systemic autoimmunity resulting in increased serum antinuclear and antiglomerular autoantibodies and (b) immunological events that occur within the target organ and result in end organ damage. Aberrations in the innate as well as adaptive arms of the immune system both play an important role in the genesis and progression of lupus. Here, we will review the present understanding - as garnered from studying mouse models - about the roles of various immune cells in lupus pathogenesis.
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Affiliation(s)
- Simanta Pathak
- Department of Internal Medicine (Rheumatology), University of Texas, Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75235, USA
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169
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Klimovich VB. IgM and its receptors: structural and functional aspects. BIOCHEMISTRY (MOSCOW) 2011; 76:534-49. [PMID: 21639833 DOI: 10.1134/s0006297911050038] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This review combines the data obtained before the beginning of the 1990s with results published during the last two decades. The predominant form of the IgM molecule is a closed ring composed of five 7S subunits and a J chain. The new model of spatial structure of the pentamer postulates nonplanar mushroom-shaped form of the molecule with the plane formed by a radially-directed Fab regions and central protruding portion consisting of Cµ4 domains. Up to the year 2000 the only known Fc-receptor for IgM was pIgR. Interaction of IgM with pIgR results in secretory IgM formation, whose functions are poorly studied. The receptor designated as Fcα/µR is able to bind IgM and IgA. It is expressed on lymphocytes, follicular dendritic cells, and macrophages. A receptor binding IgM only named FcµR has also been described. It is expressed on T- and B-lymphocytes. The discovery of new Fc-receptors for IgM requires revision of notions that interactions between humoral reactions involving IgM and the cells of the immune system are mediated exclusively by complement receptors. In the whole organism, apart from IgM induced by immunization, natural antibodies (NA) are present and comprise in adults a considerable part of the circulating IgM. NA are polyreactive, germ-line-encoded, and emerge during embryogenesis without apparent antigenic stimuli. They demonstrate a broad spectrum of antibacterial activity and serve as first line of defense against microbial and viral infections. NA may be regarded as a transitional molecular form from invariable receptors of innate immunity to highly diverse receptors of adaptive immunity. By means of interaction with autoantigens, NA participate in maintenance of immunological tolerance and in clearance of dying cells. At the same time, NA may act as a pathogenic factor in atherosclerotic lesion formation and in development of tissue damage due to ischemia/reperfusion.
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Affiliation(s)
- V B Klimovich
- Russian Research Center for Radiology and Surgical Technologies, St. Petersburg.
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170
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Stoehr AD, Schoen CT, Mertes MMM, Eiglmeier S, Holecska V, Lorenz AK, Schommartz T, Schoen AL, Hess C, Winkler A, Wardemann H, Ehlers M. TLR9 in peritoneal B-1b cells is essential for production of protective self-reactive IgM to control Th17 cells and severe autoimmunity. THE JOURNAL OF IMMUNOLOGY 2011; 187:2953-65. [PMID: 21859955 DOI: 10.4049/jimmunol.1003340] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The role of TLR9 in the development of the autoimmune disease systemic lupus erythematosus is controversial. In different mouse models of the disease, loss of TLR9 abolishes the generation of anti-nucleosome IgG autoantibodies but at the same time exacerbates lupus disease. However, the TLR9-dependent tolerance mechanism is unknown. In this study, we show that loss of TLR9 is associated with low peritoneal B-1b cell numbers and low levels of protective self-reactive IgM serum autoantibodies in lupus-prone FcγRIIB-deficient mice leading to the uncontrolled accumulation of proinflammatory CD4(+) cells and exacerbated autoimmunity. TLR7 signaling was not able to compensate for the loss of TLR9 signaling in peritoneal B-1b cells to induce IgM Abs. Transfer of TLR9-expressing peritoneal B-1b cells from FcγRIIB-deficient mice or of recombinant monoclonal self-reactive IgM Abs was sufficient to reduce the frequency of proinflammatory Th17 cells and lupus disease in FcγRIIB/TLR9 double-deficient mice. Taken together, these data provide evidence for a TLR9-dependent tolerance mechanism of peritoneal B-1b cells generating protective self-reactive IgM in lupus-prone mice to control Th17 cell development and severe autoimmunity.
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Affiliation(s)
- Alexander D Stoehr
- Laboratory of Tolerance and Autoimmunity, German Rheumatism Research Center, Leibniz Institute, 10117 Berlin, Germany
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171
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Jesus AA, Liphaus BL, Silva CA, Bando SY, Andrade LEC, Coutinho A, Carneiro-Sampaio M. Complement and antibody primary immunodeficiency in juvenile systemic lupus erythematosus patients. Lupus 2011; 20:1275-84. [PMID: 21813590 DOI: 10.1177/0961203311411598] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE To evaluate the frequency of primary immunodeficiencies (PID) in juvenile systemic lupus erythematosus (JSLE) patients. METHODS Some 72 JSLE patients were analyzed for levels of immunoglobulin classes and IgG subclasses and early components of the classical complement pathway. Determination of C4 gene copy number (GCN) and detection of type I C2 deficiency (D) were also performed. RESULTS PID was identified in 16 patients (22%): C2D in three, C4D in three, C1qD in two, IgG2D (<20 mg/dl) in four, IgAD (<7 mg/dl) in three, and IgMD (<35 mg/dl) in three; one of these patients presented IgA, C2 and C4D. Two patients had low C4 GCN and two had type I C2D. Demographic data, family history of autoimmune disease and PID, JSLE clinical findings, occurrence of infections, disease activity and therapies were similar in patients with and without PID (p > 0.05). Remarkably, the median of Systemic Lupus International Collaborating Clinics/ACR-damage index (SLICC/ACR-DI) was significantly higher in JSLE patients with PID compared with patients without these abnormalities (p = 0.0033), likewise the high frequency of SLICC/ACR-DI > 1 (p = 0.023). CONCLUSIONS A high frequency of PID was observed in JSLE patients, suggesting that these defects may contribute to lupus development. Our findings indicate that these two groups of PID should be investigated in severe pediatric lupus.
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Affiliation(s)
- A A Jesus
- Children's Hospital, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
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172
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Haroun M, M El-Sayed M. Measurement of IgG levels can serve as a biomarker in newly diagnosed diabetic children. J Clin Biochem Nutr 2011; 40:56-61. [PMID: 18437206 PMCID: PMC2291473 DOI: 10.3164/jcbn.40.56] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Accepted: 08/28/2006] [Indexed: 11/22/2022] Open
Abstract
This study was undertaken to determine humoral immune response to the presence of anti-immunoglobulin antibodies in children with newly diagnosed type 1 diabetes mellitus, using as a target cow immunoglobulins, in an attempt to elucidate further complex immuno-pathogenetic interactions of the disease. Serum immunoglobulin G (IgG) concentrations were measured by ELISA in 30 children with type 1 diabetes mellitus and 30 healthy matched normal children. It was found that normal children had a mean IgG level of 7.41 mg/ml while diabetic individuals had a mean IgG level of 8.52 mg/ml (p<0.00004). On the contrary, the mean level of IgG in diabetic sera after purification from anti-cow immunoglobulins was determined to be 7.52 mg/ml. Therefore, there was no significant difference in IgG level in patients with type 1 diabetes mellitus after removal of anti-cow immunoglobulin antibodies compared to normal children (p<0.58). Visualization of IgG and immuno-precipitation confirm that anti-cow immunoglobulins antibodies, which were unrelated to antigen, were co-precipitated with the antigen-antibody complex. A circulating immunoglobulin reacting with other immunoglobulins is thus present in children with type 1 diabetes and may well play a part in the complex immuno-pathogenetic interactions.
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Affiliation(s)
- Medhat Haroun
- Department of Bioscience & Technology, Institute of Graduate Studies & Research, Alexandria University, Alexandria, Egypt
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173
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Jiang C, Zhao ML, Scearce RM, Diaz M. Activation-induced deaminase-deficient MRL/lpr mice secrete high levels of protective antibodies against lupus nephritis. ACTA ACUST UNITED AC 2011; 63:1086-96. [PMID: 21225690 DOI: 10.1002/art.30230] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE We previously generated MRL/lpr mice deficient in activation-induced deaminase (AID) that lack isotype switching and immunoglobulin hypermutation. These mice have high levels of unmutated (germline) autoreactive IgM, yet they experienced an increase in survival and an improvement in lupus nephritis that exceeded that of MRL/lpr mice lacking IgG. The purpose of the present study was to test the hypothesis that high levels of germline autoreactive IgM in these mice confer protection against lupus nephritis. METHODS Autoreactive IgM antibodies of various specificities, including antibodies against double-stranded DNA (dsDNA), from AID-deficient MRL/lpr mice were given to asymptomatic MRL/lpr mice, and the levels of cytokines, proteinuria, immune complex deposition in the kidneys, and glomerulonephritis were examined. Novel AID-deficient MRL/lpr mice that lack any antibodies were generated for comparison to AID-deficient MRL/lpr mice that secrete only IgM. RESULTS Treatment with IgM anti-dsDNA resulted in a dramatic improvement in lupus nephritis. Other autoreactive IgM antibodies, such as antiphospholipid and anti-Sm, did not alter the pathologic changes. Secretion of proinflammatory cytokines by macrophages and the levels of inflammatory cells and apoptotic debris in the kidneys were lower in mice receiving IgM anti-dsDNA. Protective IgM derived from AID-deficient MRL/lpr mice displayed a distinct B cell repertoire, with a bias toward members of the V(H) 7183 family. CONCLUSION IgM anti-dsDNA protected MRL/lpr mice from lupus nephritis, likely by stopping the inflammatory cascade leading to kidney damage. A distinct repertoire of V(H) usage in IgM anti-dsDNA hybridomas from AID-deficient mice suggests that there is enrichment of a dedicated B cell population that secretes unmutated protective IgM in these mice.
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Affiliation(s)
- Chuancang Jiang
- National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
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174
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Litvack ML, Post M, Palaniyar N. IgM promotes the clearance of small particles and apoptotic microparticles by macrophages. PLoS One 2011; 6:e17223. [PMID: 21448268 PMCID: PMC3063157 DOI: 10.1371/journal.pone.0017223] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 01/24/2011] [Indexed: 12/20/2022] Open
Abstract
Background Antibodies are often involved in enhancing particle clearance by macrophages. Although the mechanisms of antibody-dependent phagocytosis have been studied for IgG in greater detail, very little is known about IgM-mediated clearance. It has been generally considered that IgM does not support phagocytosis. Recent studies indicate that natural IgM is important to clear microbes and other bioparticles, and that shape is critical to particle uptake by macrophages; however, the relevance of IgM and particle size in their clearance remains unclear. Here we show that IgM has a size-dependent effect on clearance. Methodology/Principal Findings We used antibody-opsonized sheep red blood cells, different size beads and apoptotic cells to determine the effect of human and mouse IgM on phagocytosis by mouse alveolar macrophages. Our microscopy (light, epifluorescence, confocal) and flow cytometry data show that IgM greatly enhances the clearance of small particles (about 1–2 micron) by these macrophages. There is an inverse relationship between IgM-mediated clearance by macrophages and the particle size; however, macrophages bind and internalize many different size particles coated with IgG. We also show that IgM avidly binds to small size late apoptotic cells or bodies (2–5 micron) and apoptotic microparticles (<2 µm) released from dying cells. IgM also promotes the binding and uptake of microparticle-coated beads. Conclusions/Significance Therefore, while the shape of the particles is important for non-opsonized particle uptake, the particle size matters for antibody-mediated clearance by macrophages. IgM particularly promotes the clearance of small size particles. This finding may have wider implications in IgM-mediated clearing of antigens, microbial pathogens and dying cells by the host.
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Affiliation(s)
- Michael L. Litvack
- Lung Innate Immunity Research Laboratory, The Hospital for Sick Children, Toronto, Ontario, Canada
- Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Martin Post
- Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Nades Palaniyar
- Lung Innate Immunity Research Laboratory, The Hospital for Sick Children, Toronto, Ontario, Canada
- Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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175
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Madi A, Kenett DY, Bransburg-Zabary S, Merbl Y, Quintana FJ, Tauber AI, Cohen IR, Ben-Jacob E. Network theory analysis of antibody-antigen reactivity data: the immune trees at birth and adulthood. PLoS One 2011; 6:e17445. [PMID: 21408156 PMCID: PMC3050881 DOI: 10.1371/journal.pone.0017445] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2010] [Accepted: 02/03/2011] [Indexed: 01/04/2023] Open
Abstract
MOTIVATION New antigen microarray technology enables parallel recording of antibody reactivities with hundreds of antigens. Such data affords system level analysis of the immune system's organization using methods and approaches from network theory. Here we measured the reactivity of 290 antigens (for both the IgG and IgM isotypes) of 10 healthy mothers and their term newborns. We constructed antigen correlation networks (or immune networks) whose nodes are the antigens and the edges are the antigen-antigen reactivity correlations, and we also computed their corresponding minimum spanning trees (MST)--maximal information reduced sub-graphs. We quantify the network organization (topology) in terms of the network theory divergence rate measure and rank the antigen importance in the full antigen correlation networks by the eigen-value centrality measure. This analysis makes possible the characterization and comparison of the IgG and IgM immune networks at birth (newborns) and adulthood (mothers) in terms of topology and node importance. RESULTS Comparison of the immune network topology at birth and adulthood revealed partial conservation of the IgG immune network topology, and significant reorganization of the IgM immune networks. Inspection of the antigen importance revealed some dominant (in terms of high centrality) antigens in the IgG and IgM networks at birth, which retain their importance at adulthood.
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Affiliation(s)
- Asaf Madi
- School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Dror Y. Kenett
- School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
| | - Sharron Bransburg-Zabary
- School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yifat Merbl
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Francisco J. Quintana
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
- Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Alfred I. Tauber
- School of Medicine, Boston University, Boston, Massachusetts, United States of America
| | - Irun R. Cohen
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
- * E-mail: (IRC); (EBC)
| | - Eshel Ben-Jacob
- School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
- Center for Theoretical and Biological Physics, University of California San Diego, La Jolla, California, United States of America
- * E-mail: (IRC); (EBC)
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176
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Notley CA, Brown MA, Wright GP, Ehrenstein MR. Natural IgM Is Required for Suppression of Inflammatory Arthritis by Apoptotic Cells. THE JOURNAL OF IMMUNOLOGY 2011; 186:4967-72. [DOI: 10.4049/jimmunol.1003021] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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177
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Isono M, Araki H, Haitani T, Morita Y, Yasuda M, Kato N, Urasaki K, Tsujimura Y. Diffuse alveolar hemorrhage in lupus nephritis complicated by microscopic polyangiitis. Clin Exp Nephrol 2011; 15:294-8. [PMID: 21225308 DOI: 10.1007/s10157-010-0394-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 12/08/2010] [Indexed: 11/30/2022]
Abstract
Diffuse alveolar hemorrhage (DAH) is a rare but fatal complication in patients with systemic lupus erythematosus (SLE). We describe a case of a 74-year-old woman who presented with DAH as an initial presentation of SLE. She also had microscopic polyangiitis clinically manifesting as crescentic glomerulonephritis and purpura with positive myeloperoxidase (MPO)-antineutrophil cytoplasmic antibodies (ANCA). The patient transiently improved when treated with plasma exchange and methylprednisolone pulse therapy; however, she died of recurrent pulmonary hemorrhage and concurrent cryptococcal pneumonia. This case indicates that MPO-ANCA is associated with severe organ involvement such as pulmonary hemorrhage and crescentic glomerulonephritis in SLE.
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Affiliation(s)
- Motohide Isono
- Department of Medicine, Otsu Municipal Hospital, Otsu, Shiga 520-0804, Japan.
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178
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Kim J. Identification of a human monoclonal natural IgM antibody that recognizes early apoptotic cells and promotes phagocytosis. Hybridoma (Larchmt) 2010; 29:275-81. [PMID: 20715985 DOI: 10.1089/hyb.2010.0012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Efficient clearance of cells undergoing apoptotic death is crucial for normal tissue homeostasis and for the prevention of autoimmunity. Engulfment of apoptotic cells is finely regulated by a highly redundant system of receptors and bridging molecules. We developed a rapid and efficient method for the identification of human natural IgM antibodies and isolated some natural human monoclonal IgM antibodies specific to the apoptotic cells. Among them, AC34 IgM bound to early apoptotic cells and promoted phagocytosis of apoptotic Jurkat cells by human monocyte-derived macrophage (HMDM). AC34 IgM recognized phosphatidylserine (PS), which means PS might be a possible molecule recognized by AC34 IgM on the surface of apoptotic cells and AC34 IgM might be a possible candidate of bridging molecules between the PS and phagocytes. The sequences of V(H) and V(L) of AC34 were almost the same with their germline counterpart. Our experiments suggest a role of natural IgM as an opsonin in the clearance of early apoptotic cells.
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Affiliation(s)
- Jinoh Kim
- Department of Rheumatology, University of Washington, Seattle, Washington 98195, USA.
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179
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Baumgarth N. The double life of a B-1 cell: self-reactivity selects for protective effector functions. Nat Rev Immunol 2010; 11:34-46. [PMID: 21151033 DOI: 10.1038/nri2901] [Citation(s) in RCA: 657] [Impact Index Per Article: 46.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
During their development, B and T cells with self-reactive antigen receptors are generally deleted from the repertoire to avoid autoimmune diseases. Paradoxically, innate-like B-1 cells in mice are positively selected for self-reactivity and form a pool of long-lived, self-renewing B cells that produce most of the circulating natural IgM antibodies. This Review provides an overview of the developmental processes that shape the B-1 cell pool in mice, outlines the functions of B-1 cells in both the steady state and during host defence, and discusses possible functional B-1 cell homologues that exist in humans.
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Affiliation(s)
- Nicole Baumgarth
- Center for Comparative Medicine, University of California, Davis, California 95616, USA.
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180
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Long KK, Pavlath GK, Montano M. Sca-1 influences the innate immune response during skeletal muscle regeneration. Am J Physiol Cell Physiol 2010; 300:C287-94. [PMID: 21123737 DOI: 10.1152/ajpcell.00319.2010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Efficient muscle regeneration requires the clearance of dead and dying tissue via phagocytosis before remodeling. We have previously shown that mice lacking stem cell antigen-1 (Sca-1) display a defect in skeletal muscle regeneration characterized by increased fibrosis and decreased turnover of the extracellular matrix. In the present study we demonstrate that Sca-1(-/-) mice have a defect in their capacity to recruit soluble IgM, and subsequently C3 complement, to damaged muscle. We hypothesize that this defect in recruitment delays or decreases phagocytosis by macrophages, contributing to the previously observed fibrotic phenotype of these mice. As the primary source of soluble IgM is peritoneal B-1a cells, which are a subset of self-renewing B cells, we analyzed this cell population and observed a significant reduction in B-1a cells in Sca-1(-/-) animals. Interestingly, these mice are protected from ischemia-reperfusion injury, an acute inflammatory reaction also mediated by IgM and C3 complement that has been linked to a deficit in B-1a cells in previous studies. Collectively, these data reveal a novel role for Sca-1 in innate immunity during muscle regeneration and indicate that further elucidation of immuno-myogenic processes will help to better understand and promote muscle regeneration.
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Affiliation(s)
- Kimberly K Long
- Boston Medical Center, Department of Medicine, Section of Infectious Diseases, Boston, Massachusetts, USA
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181
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Abstract
The existence of IgM has been known for more than a century, but its importance in immunity and autoimmunity continues to emerge. Studies of mice deficient in secreted IgM have provided unexpected insights into its role in several diverse processes, from B cell survival to atherosclerosis, as well as in autoimmunity and protection against infection. Among the various distinct properties that underlie the functions of IgM, two stand out: its polyreactivity and its ability to facilitate the removal of apoptotic cells. In addition, new B cell-targeted therapies for the treatment of autoimmunity have been shown to cause a reduction in serum IgM, potentially disrupting the functions of this immunoregulatory molecule and increasing susceptibility to infection.
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182
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Poloxamer 188 protects against ischemia-reperfusion injury in a murine hind-limb model. Plast Reconstr Surg 2010; 125:1651-1660. [PMID: 20517088 DOI: 10.1097/prs.0b013e3181ccdbef] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Ischemia-reperfusion injury can activate pathways generating reactive oxygen species, which can injure cells by creating holes in the cell membranes. Copolymer surfactants such as poloxamer 188 are capable of sealing defects in cell membranes. The authors postulated that a single-dose administration of poloxamer 188 would decrease skeletal myocyte injury and mortality following ischemia-reperfusion injury. METHODS Mice underwent normothermic hind-limb ischemia for 2 hours. Animals were treated with 150 microl of poloxamer 188 or dextran at three time points: (1) 10 minutes before ischemia; (2) 10 minutes before reperfusion; and (3) 2 or 4 hours after reperfusion. After 24 hours of reperfusion, tissues were analyzed for myocyte injury (histology) and metabolic dysfunction (muscle adenosine 5'-triphosphate). Additional groups of mice were followed for 7 days to assess mortality. RESULTS When poloxamer 188 treatment was administered 10 minutes before ischemia, injury was reduced by 84 percent, from 50 percent injury in the dextran group to 8 percent injury in the poloxamer 188 group (p < 0.001). When administered 10 minutes before reperfusion, poloxamer 188 animals demonstrated a 60 percent reduction in injury compared with dextran controls (12 percent versus 29 percent). Treatment at 2 hours, but not at 4 hours, postinjury prevented substantial myocyte injury. Preservation of muscle adenosine 5'-triphosphate paralleled the decrease in myocyte injury in poloxamer 188-treated animals. Poloxamer 188 treatment significantly reduced mortality following injury (10 minutes before, 75 percent versus 25 percent survival, p = 0.0077; 2 hours after, 50 percent versus 8 percent survival, p = 0.032). CONCLUSION Poloxamer 188 administered to animals decreased myocyte injury, preserved tissue adenosine 5'-triphosphate levels, and improved survival following hind-limb ischemia-reperfusion injury.
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Oliveira GMD, Masuda MO, Rocha NN, Schor N, Hooper CS, Araújo-Jorge TCD, Henriques-Pons A. Absence of Fas-L aggravates renal injury in acute Trypanosoma cruzi infection. Mem Inst Oswaldo Cruz 2010; 104:1063-71. [PMID: 20140366 DOI: 10.1590/s0074-02762009000800002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 10/13/2009] [Indexed: 01/28/2023] Open
Abstract
Trypanosoma cruzi infection induces diverse alterations in immunocompetent cells and organs, myocarditis and congestive heart failure. However, the physiological network of disturbances imposed by the infection has not been addressed thoroughly. Regarding myocarditis induced by the infection, we observed in our previous work that Fas-L-/- mice (gld/gld) have very mild inflammatory infiltration when compared to BALB/c mice. However, all mice from both lineages die in the early acute phase. Therefore, in this work we studied the physiological connection relating arterial pressure, renal function/damage and cardiac insufficiency as causes of death. Our results show that a broader set of dysfunctions that could be classified as a cardio/anaemic/renal syndrome is more likely responsible for cardiac failure and death in both lineages. However, gld/gld mice had very early glomerular deposition of IgM and a more intense renal inflammatory response with reduced renal filtration, which is probably responsible for the premature death in the absence of significant myocarditis in gld/gld.
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184
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Notley CA, Baker N, Ehrenstein MR. Secreted IgM Enhances B Cell Receptor Signaling and Promotes Splenic but Impairs Peritoneal B Cell Survival. THE JOURNAL OF IMMUNOLOGY 2010; 184:3386-93. [DOI: 10.4049/jimmunol.0902640] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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185
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Barabas AZ, Cole CD, Barabas AD, Graeff RM, Lafreniere R, Weir DM. Modified Vaccination Technique for Prophylactic and Therapeutic Applications to Combat Endogenous Antigen-Induced Disorders. Scand J Immunol 2010; 71:125-33. [DOI: 10.1111/j.1365-3083.2009.02360.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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186
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Jung MY, Kang SW, Kim SK, Kim HJ, Yun DH, Yim SV, Hong SJ, Chung JH. The interleukin-1 family gene polymorphisms in Korean patients with rheumatoid arthritis. Scand J Rheumatol 2010; 39:190-6. [DOI: 10.3109/03009740903447028] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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187
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Taguchi M, Kihara Y, Nagashio Y, Yamamoto M, Otsuki M, Harada M. Decreased production of immunoglobulin M and A in autoimmune pancreatitis. J Gastroenterol 2010; 44:1133-9. [PMID: 19626266 DOI: 10.1007/s00535-009-0106-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Accepted: 06/29/2009] [Indexed: 02/04/2023]
Abstract
BACKGROUND Autoimmune pancreatitis (AIP) is a rare type of chronic pancreatitis caused by an autoimmune abnormality. It is well known that high serum concentrations of IgG4 are helpful for making a diagnosis of AIP; however, it is unclear whether there are abnormalities in the production of other immunoglobulins in AIP. METHODS We examined the immune condition of AIP patients before and after glucocorticoid treatment, focusing on serum levels of IgG, IgG4, IgM and IgA, and compared the results with those in other hepato-pancreatic diseases, such as autoimmune hepatitis, primary biliary cirrhosis, chronic pancreatitis and pancreatic carcinoma. RESULTS IgM and IgA were decreased in patients with untreated AIP. IgM and IgG or IgG4 were negatively correlated in patients with AIP. The ratios of IgG to IgM and IgG to IgA in patients with AIP were significantly increased compared with the other diseases. The diagnostic sensitivity of IgG to IgM and IgG to IgA was 0.800 and 0.950, and the specificity of each ratio was 0.703 and 0.728, respectively, in the differentiation of AIP from the other diseases. IgM was not significantly changed after glucocorticoid treatment in the patients with AIP, while IgG, IgG4 and IgA decreased. CONCLUSIONS The ratios of IgG to IgM and IgG to IgA may serve as novel diagnostic markers to differentiate AIP from other hepato-pancreatic diseases. Furthermore, low concentrations of IgM and IgA may be involved in the pathogenesis of AIP.
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Affiliation(s)
- Masashi Taguchi
- Third Department of Internal Medicine, University of Occupational and Environmental Health, Japan School of Medicine, Yahatanishi-ku, Kitakyushu, Japan.
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188
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Application of the modified vaccination technique for the prevention and cure of chronic ailments. ASIAN PAC J TROP MED 2010. [DOI: 10.1016/s1995-7645(10)60060-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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189
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Poon IKH, Hulett MD, Parish CR. Molecular mechanisms of late apoptotic/necrotic cell clearance. Cell Death Differ 2009; 17:381-97. [PMID: 20019744 DOI: 10.1038/cdd.2009.195] [Citation(s) in RCA: 243] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phagocytosis serves as one of the key processes involved in development, maintenance of tissue homeostasis, as well as in eliminating pathogens from an organism. Under normal physiological conditions, dying cells (e.g., apoptotic and necrotic cells) and pathogens (e.g., bacteria and fungi) are rapidly detected and removed by professional phagocytes such as macrophages and dendritic cells (DCs). In most cases, specific receptors and opsonins are used by phagocytes to recognize and bind their target cells, which can trigger the intracellular signalling events required for phagocytosis. Depending on the type of target cell, phagocytes may also release both immunomodulatory molecules and growth factors to orchestrate a subsequent immune response and wound healing process. In recent years, evidence is growing that opsonins and receptors involved in the removal of pathogens can also aid the disposal of dying cells at all stages of cell death, in particular plasma membrane-damaged cells such as late apoptotic and necrotic cells. This review provides an overview of the molecular mechanisms and the immunological outcomes of late apoptotic/necrotic cell removal and highlights the striking similarities between late apoptotic/necrotic cell and pathogen clearance.
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Affiliation(s)
- I K H Poon
- John Curtin School of Medical Research, Australian National University, Canberra, 2601, Australia
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Chen L, Guo L, Tian J, Zheng B, Han S. Deficiency in activation-induced cytidine deaminase promotes systemic autoimmunity in lpr mice on a C57BL/6 background. Clin Exp Immunol 2009; 159:169-75. [PMID: 19922498 DOI: 10.1111/j.1365-2249.2009.04058.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Activation-induced deaminase (AID) is a prerequisite for immunoglobulin (Ig) class-switch recombination and somatic hypermutation, which is critical for antibody affinity maturation. IgM and IgG autoantibodies are characteristic of the systemic autoimmune disorders such as lupus. However, the relative contributions of hypermutated high-affinity IgG antibodies and germline-encoded IgM antibodies to systemic autoimmunity are not defined fully. The role of AID in autoimmunity is unclear. The current study used AID-deficient mice to investigate the role of AID in the development and pathogenesis of murine lupus. C57BL/6 mice deficient in both Fas and AID were generated. Compared to their AID-competent littermates, AID(-/-) lymphoproliferative (lpr) mice produced significantly elevated levels of IgM autoreactive antibodies with enhanced germinal centre (GC) response, developed more advanced splenomegaly and exhibited more severe glomerulonephritis. Thus, AID may play an important role in the negative regulation of systemic autoimmune manifestations in murine lupus. The results also indicate that hypermutated high-affinity IgG antibodies are not necessary for the development of autoimmune syndrome in lpr mice on a C57BL/6 background.
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Affiliation(s)
- L Chen
- Department of Immunology, Baylor College of Medicine, Houston, TX, USA
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191
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Lewis MJ, Malik TH, Ehrenstein MR, Boyle JJ, Botto M, Haskard DO. Immunoglobulin M is required for protection against atherosclerosis in low-density lipoprotein receptor-deficient mice. Circulation 2009; 120:417-26. [PMID: 19620499 DOI: 10.1161/circulationaha.109.868158] [Citation(s) in RCA: 188] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Immunoglobulin M (IgM) natural antibodies bind oxidatively-modified low-density lipoprotein (LDL) and apoptotic cells and have been implicated as being important for protection against atherosclerosis. We have directly investigated the requirement for IgM by studying the effects of IgM deficiency in LDL receptor-deficient (Ldlr(-/-)) mice. METHODS AND RESULTS Mice deficient in serum IgM (sIgM) or complement C1q were crossed with Ldlr(-/-) mice and studied on both low-fat and high-fat semisynthetic diets. On both diets, en face and aortic root atherosclerotic lesions in sIgM.Ldlr(-/-) mice were substantially larger and more complex, with accelerated cholesterol crystal formation and increased smooth muscle cell content in aortic root lesions. Combined C1q and IgM deficiency had the same effect as IgM deficiency alone. Increased apoptosis was observed in aortic root lesions of both sIgM.Ldlr(-/-) and C1qa.Ldlr(-/-) mice. Because lesions were significantly larger in IgM-deficient mice than in the absence of C1q, IgM protective mechanisms appear to be partially independent of classical pathway activation and apoptotic cell clearance. Levels of IgG antibodies against copper-oxidized LDL were lower in sIgM.Ldlr(-/-) mice fed a high-fat diet, suggesting compensatory consumption of IgG in the absence of IgM. CONCLUSIONS This study provides direct evidence that IgM antibodies play a central role in protection against atherosclerosis. The mechanism appears to be at least partly independent of classical pathway complement activation by C1q.
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Affiliation(s)
- Myles J Lewis
- BHF Cardiovascular Medicine Unit, National Heart and Lung Institute, Imperial College, Hammersmith Hospital, Du Cane Rd, London, W12 0NN, UK
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192
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Chen Y, Khanna S, Goodyear CS, Park YB, Raz E, Thiel S, Grönwall C, Vas J, Boyle DL, Corr M, Kono DH, Silverman GJ. Regulation of dendritic cells and macrophages by an anti-apoptotic cell natural antibody that suppresses TLR responses and inhibits inflammatory arthritis. THE JOURNAL OF IMMUNOLOGY 2009; 183:1346-59. [PMID: 19564341 DOI: 10.4049/jimmunol.0900948] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Although natural Abs (NAbs) are present from birth, little is known about what drives their selection and whether they have housekeeping functions. The prototypic T15-NAb, first identified because of its protective role in infection, is representative of a special type of NAb response that specifically recognizes and forms complexes with apoptotic cells and which promotes cell-corpse engulfment by phagocytes. We now show that this T15-NAb IgM-mediated clearance process is dependent on the recruitment of C1q and mannose-binding lectin, which have known immune modulatory activities that also provide "eat me" signals for enhancing phagocytosis. Further investigation revealed that the addition of T15-NAb significantly suppressed in vitro LPS-induced TNF-alpha and IL-6 secretion by the macrophage-like cell line, RAW264.7, as well as TLR3-, TLR4-, TLR7-, and TLR9-induced maturation and secretion of a range of proinflammatory cytokines and chemokines by bone marrow-derived conventional dendritic cells. Significantly, high doses of this B-1 cell produced NAb also suppressed in vivo TLR-induced proinflammatory responses. Although infusions of apoptotic cells also suppressed such in vivo inflammatory responses and this effect was associated with the induction of high levels of IgM antiapoptotic cell Abs, apoptotic cell treatment was not effective at suppressing such TLR responses in B cell-deficient mice. Moreover, infusions of T15-NAb also efficiently inhibited both collagen-induced arthritis and anti-collagen II Ab-mediated arthritis. These studies identify and characterize a previously unknown regulatory circuit by which a NAb product of innate-like B cells aids homeostasis by control of fundamental inflammatory pathways.
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Affiliation(s)
- Yifang Chen
- Laboratory of B Cell Immunobiology, University of California, San Diego, La Jolla, CA 92093, USA
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193
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Martinez-Valle F, Balada E, Ordi-Ros J, Bujan-Rivas S, Sellas-Fernandez A, Vilardell-Tarres M. DNase 1 activity in patients with systemic lupus erythematosus: relationship with epidemiological, clinical, immunological and therapeutical features. Lupus 2009; 18:418-23. [PMID: 19318394 DOI: 10.1177/0961203308098189] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The main objective of this study is to determine the relationship between the activity of DNase1 and the clinical and immunological features in patients with systemic lupus erythematosus (SLE). A total of 66 patients (8 men and 58 women) diagnosed with SLE according to the American College of Rheumatology (ACR) SLE classification criteria were included in the study. Sixty-two sera from healthy blood donors were also included as controls. Epidemiological, clinical, immunological and therapeutical features for each patient were obtained. Disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). DNase1 activity was determined by using a radial enzyme diffusion method. Statistical analysis was performed using SPSS 12.0 software, with significant P value <0.05. Dnase1 activity was lower in patients with SLE than in the control group: 13.69 +/- 8.52 mug/mL vs 24.75 +/- 12.32 mug/mL, respectively (P < 0.005). No statistical relationship was found between DNase1 activity and disease evolution time, hypertension, presence of absolute or relative proteinuria, SLEDAI, new clinical manifestations, anti-Ro antibodies, anti-La antibodies, anti-RNP antibodies, anti-DNA antibodies, anti-cardiolipin antibodies, lupus anticoagulant, or with the treatment pattern received by the patients. Although important differences in DNase1 activity were found between patients with or without anti-Sm antibodies, they did not reach statistical significance. DNase1 activity was significantly lower in patients with SLE. Nevertheless, we did not find further relationships with any other of the epidemiological, clinical, immunological or therapeutical variables considered.
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Affiliation(s)
- F Martinez-Valle
- Research Unit in Systemic Autoimmune Diseases, Vall d'Hebron Research Institute, Hospital Vall d'Hebron, Barcelona, Spain
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194
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Enhanced humoral immune responses against T-independent antigens in Fc alpha/muR-deficient mice. Proc Natl Acad Sci U S A 2009; 106:11230-5. [PMID: 19549827 DOI: 10.1073/pnas.0809917106] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
IgM is an antibody class common to all vertebrates that plays a primary role in host defenses against infection. Binding of IgM with an antigen initiates the complement cascade, accelerating cellular and humoral immune responses. However, the functional role of the Fc receptor for IgM in such immune responses remains obscure. Here we show that mice deficient in Fc alpha/muR, an Fc receptor for IgM expressed on B cells and follicular dendritic cells (FDCs), have enhanced germinal center formation and affinity maturation and memory induction of IgG3(+) B cells after immunization with T-independent (TI) antigens. Moreover, Fc alpha/muR-deficient mice show prolonged antigen retention by marginal zone B (MZB) cells and FDCs. In vitro studies demonstrate that interaction of the IgM immune complex with Fc alpha/muR partly suppress TI antigen retention by MZB cells. We further show that downregulation of complement receptor (CR)1 and CR2 or complement deprivation by in vivo injection with anti-CR1/2 antibody or cobra venom factor attenuates antigen retention by MZB cells and germinal center formation after immunization with TI antigens in Fc alpha/muR(-/-) mice. Taken together, these results suggest that Fc alpha/muR negatively regulates TI antigen retention by MZB cells and FDCs, leading to suppression of humoral immune responses against T-independent antigens.
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195
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Improved Survival of Murine Island Skin Flaps by Prevention of Reperfusion Injury. Plast Reconstr Surg 2009; 123:1431-1439. [DOI: 10.1097/prs.0b013e3181a071e8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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196
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Chou MY, Fogelstrand L, Hartvigsen K, Hansen LF, Woelkers D, Shaw PX, Choi J, Perkmann T, Bäckhed F, Miller YI, Hörkkö S, Corr M, Witztum JL, Binder CJ. Oxidation-specific epitopes are dominant targets of innate natural antibodies in mice and humans. J Clin Invest 2009; 119:1335-49. [PMID: 19363291 DOI: 10.1172/jci36800] [Citation(s) in RCA: 365] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Accepted: 02/25/2009] [Indexed: 12/31/2022] Open
Abstract
Atherosclerosis is a chronic inflammatory disease characterized by the accumulation of oxidized lipoproteins and apoptotic cells. Adaptive immune responses to various oxidation-specific epitopes play an important role in atherogenesis. However, accumulating evidence suggests that these epitopes are also recognized by innate receptors, such as scavenger receptors on macrophages, and plasma proteins, such as C-reactive protein (CRP). Here, we provide multiple lines of evidence that oxidation-specific epitopes constitute a dominant, previously unrecognized target of natural Abs (NAbs) in both mice and humans. Using reconstituted mice expressing solely IgM NAbs, we have shown that approximately 30% of all NAbs bound to model oxidation-specific epitopes, as well as to atherosclerotic lesions and apoptotic cells. Because oxidative processes are ubiquitous, we hypothesized that these epitopes exert selective pressure to expand NAbs, which in turn play an important role in mediating homeostatic functions consequent to inflammation and cell death, as demonstrated by their ability to facilitate apoptotic cell clearance. These findings provide novel insights into the functions of NAbs in mediating host homeostasis and into their roles in health and diseases, such as chronic inflammatory diseases and atherosclerosis.
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Affiliation(s)
- Meng-Yun Chou
- Department of Medicine, UCSD, La Jolla, California 92093, USA
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197
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Wu O, Chen GP, Chen H, Li XP, Xu JH, Zhao SS, Sheng J, Feng JB, Cai J, Fang XH, Zhang WH, Li LH, Zhang N, Li J, Li JJ, Pan FM, Wang CZ, Ye DQ. The expressions of Toll-like receptor 9 and T-bet in circulating B and T cells in newly diagnosed, untreated systemic lupus erythematosus and correlations with disease activity and laboratory data in a Chinese population. Immunobiology 2008; 214:392-402. [PMID: 19362685 DOI: 10.1016/j.imbio.2008.10.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 09/29/2008] [Accepted: 10/05/2008] [Indexed: 10/21/2022]
Abstract
Toll-like receptor 9 (TLR9) plays a controversial role in the pathogenesis of systemic lupus erythematosus (SLE). T-bet may be involved in the processes between the initiation of TLR9 activation and the antibodies' production. To clarify the paradox of TLR9, we investigated the intracellular expressions of TLR9 and T-bet in B and T cells in peripheral blood samples from 35 newly diagnosed, untreated patients with SLE and 16 healthy subjects by flow cytometry (FCM). And we collected the clinic laboratory data obtained from the same individual blood sample tested by FCM each time. And the correlations among the expression levels of the two proteins and SLE laboratory data were calculated. We found the percentages of B cells expressing TLR9 and T-bet and of T cells expressing TLR9 were significantly elevated in SLE patients when compared with healthy controls. There was a significantly negative relationship between the proportion of B cells expressing TLR9 and SLE Disease Activity Index (SLEDAI) score. The serum levels of anti-dsDNA antibody reversely correlated with the mean fluorescence intensity (MFI) of B cells co-expressing T-bet and TLR9. The serum levels of anti-C1q antibody significantly associated with the proportion of B cells expressing T-bet. Also, the serum levels of IgM and IgA antibodies both significantly correlated with TLR9 and T-bet expressions in T and B cells. According to the immunological pathway knowledge and the mutually verified associations, the following conclusions are made. Expressions of TLR9 and T-bet were increased in patients with SLE. TLR9 may have a role to play in protecting against lupus. And the increase of the co-expression of TLR9 and T-bet may be of benefit to the protective antibodies' production and pathogenic antibodies' decline, and could be regarded as a good sign for lupus demission and/or treatment.
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Affiliation(s)
- Ou Wu
- Department of Epidemiology & Biostatistics, Anhui Medical University, Anhui, PR China
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198
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Lutz HU, Binder CJ, Kaveri S. Naturally occurring auto-antibodies in homeostasis and disease. Trends Immunol 2008; 30:43-51. [PMID: 19058756 DOI: 10.1016/j.it.2008.10.002] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Revised: 10/23/2008] [Accepted: 10/27/2008] [Indexed: 12/24/2022]
Abstract
Antibodies with germline or close to germline configuration exist in vertebrates, and these so-called 'naturally occurring auto-antibodies' (NAb) are directed to self and altered self components. Such NAbs have been attracting increasing interest because several of them, including some in their recombinant forms, have therapeutic potential. Whereas a large number of IgM and IgG NAbs have tissue homeostatic roles, others modulate and regulate cellular and enzyme properties. This review describes some of these NAbs and emphasizes how these low-titer, low-affinity NAbs interact with self and altered self and show functional potency in homeostasis and regulation, in addition to in diseases such as infarction and systemic inflammatory response syndrome.
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Affiliation(s)
- Hans U Lutz
- Institute of Biochemistry, ETH Zurich, CH 8093 Zurich, Switzerland.
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199
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Abstract
IgG antibodies against dsDNA are involved in the pathogenesis of systemic lupus erythematosus (SLE) glomerulonephritis. In contrast, glomerulonephritis is rare in SLE patients with IgM antibodies against dsDNA. Therefore, a possible protective effect of IgM antibodies has been studied in more detail. In murine models of SLE, the lack of secreted IgM was associated with more severe glomerulonephritis. In more recent studies, the treatment of lupus-prone mice with a murine IgM monoclonal antibody against dsDNA prevented renal damage. Furthermore, the clearance of pathogenic immune complexes may be improved by IgM. Therefore, IgM antibodies against dsDNA are indeed protective and may be a new treatment modality of lupus nephritis in humans.
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200
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Irf4 is a positional and functional candidate gene for the control of serum IgM levels in the mouse. Genes Immun 2008; 10:93-9. [PMID: 18818690 DOI: 10.1038/gene.2008.73] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Natural IgM are involved in numerous immunological functions but the genetic factors that control the homeostasis of its secretion and upholding remain unknown. Prompted by the finding that C57BL/6 mice had significantly lower serum levels of IgM when compared with BALB/c mice, we performed a genome-wide screen and found that the level of serum IgM was controlled by a QTL on chromosome 13 reaching the highest level of association at marker D13Mit266 (LOD score=3.54). This locus was named IgMSC1 and covered a region encompassing the interferon-regulatory factor 4 gene (Irf4). The number of splenic mature B cells in C57BL/6 did not differ from BALB/c mice but we found that low serum levels of IgM in C57BL/6 mice correlated with lower frequency of IgM-secreting cells in the spleen and in the peritoneal cavity. These results suggested that C57BL/6 mice have lower efficiency in late B-cell maturation, a process that is highly impaired in Irf4 knockout mice. In fact, we also found reduced Irf4 gene expression in B cells of C57BL/6 mice. Thus, we propose Irf4 as a candidate for the IgMSC1 locus, which controls IgM homeostatic levels at the level of B-cell terminal differentiation.
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