Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 35
Filtrar
Mais filtros

País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Cancer Immunol Immunother ; 73(4): 67, 2024 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-38430241

RESUMO

Neutrophils are known to contribute in many aspects of tumor progression and metastasis. The presence of neutrophils or neutrophil-derived mediators in the tumor microenvironment has been associated with poor prognosis in several types of solid tumors. However, the effects of classical cancer treatments such as radiation therapy on neutrophils are poorly understood. Furthermore, the cellular composition and distribution of immune cells in the tumor is of increasing interest in cancer research and new imaging technologies allow to perform more complex spatial analyses within tumor tissues. Therefore, we aim to offer novel insight into intra-tumoral formation of cellular neighborhoods and communities in murine breast cancer. To address this question, we performed image mass cytometry on tumors of the TS/A breast cancer tumor model, performed spatial neighborhood analyses of the tumor microenvironment and quantified neutrophil-extracellular trap degradation products in serum of the mice. We show that irradiation with 2 × 8 Gy significantly alters the cellular composition and spatial organization in the tumor, especially regarding neutrophils and other cells of the myeloid lineage. Locally applied radiotherapy further affects neutrophils in a systemic manner by decreasing the serum neutrophil extracellular trap concentrations which correlates positively with survival. In addition, the intercellular cohesion is maintained due to radiotherapy as shown by E-Cadherin expression. Radiotherapy, therefore, might affect the epithelial-mesenchymal plasticity in tumors and thus prevent metastasis. Our findings underscore the growing importance of the spatial organization of the tumor microenvironment, particularly with respect to radiotherapy, and provide insight into potential mechanisms by which radiotherapy affects epithelial-mesenchymal plasticity and tumor metastasis.


Assuntos
Armadilhas Extracelulares , Neoplasias , Camundongos , Animais , Neutrófilos , Microambiente Tumoral
2.
Clin Exp Immunol ; 189(3): 372-382, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28509333

RESUMO

The goal of this study was to investigate the glycosylation profile of native immunoglobulin (Ig)G present in serum immune complexes in patients with rheumatoid arthritis (RA). To accomplish this, lectin binding assays, detecting the accessibility of glycans present on IgG-containing immune complexes by biotinylated lectins, were employed. Lectins capturing fucosyl residues (AAL), fucosylated tri-mannose N-glycan core sites (LCA), terminal sialic acid residues (SNA) and O-glycosidically linked galactose/N-acetylgalactosamine (GalNac-L) were used. Patients with recent-onset RA at baseline and after 3-year follow-up were investigated. We found that native IgG was complexed significantly more often with IgM, C1q, C3c and C-reactive protein (CRP) in RA patients, suggesting alterations of the native structure of IgG. The total accessibility of fucose residues on captured immune complexes to the respective lectin was significantly higher in patients with RA. Moreover, fucose accessibility on IgG-containing immune complexes correlated positively with the levels of antibodies to cyclic citrullinated peptides (anti-CCP). We also observed a significantly higher accessibility to sialic acid residues and galactose/GalNAc glyco-epitopes in native complexed IgG of patients with RA at baseline. While sialic acid accessibility increased during treatment, the accessibility of galactose/GalNAc decreased. Hence, successful treatment of RA was associated with an increase in the SNA/GalNAc-L ratio. Interestingly, the SNA/GalNAc-L ratio in particular rises after glucocorticoid treatment. In summary, this study shows the exposure of glycans in native complexed IgG of patients with early RA, revealing particular glycosylation patterns and its changes following pharmaceutical treatment.


Assuntos
Complexo Antígeno-Anticorpo/imunologia , Artrite Reumatoide/imunologia , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Polissacarídeos/química , Polissacarídeos/imunologia , Adulto , Idoso , Complexo Antígeno-Anticorpo/química , Artrite Reumatoide/terapia , Proteína C-Reativa/imunologia , Proteína C-Reativa/metabolismo , Complemento C1q/imunologia , Complemento C1q/metabolismo , Complemento C3c/imunologia , Complemento C3c/metabolismo , Feminino , Fucose/metabolismo , Galactose/metabolismo , Glicosilação , Humanos , Imunoglobulina A/imunologia , Imunoglobulina A/metabolismo , Imunoglobulina G/química , Imunoglobulina G/metabolismo , Imunoglobulina M/metabolismo , Lectinas/metabolismo , Masculino , Pessoa de Meia-Idade , Polissacarídeos/metabolismo , Sambucus nigra , Ácidos Siálicos/metabolismo
3.
Clin Exp Immunol ; 184(1): 110-7, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26618514

RESUMO

The Fc portion of immunoglobulin (Ig)G harbours a single glycosylation site. Glycan sialylation is critical for structure and for certain effector functions of IgG. Anti-histone IgG of patients with systemic lupus erythematosus is reportedly responsible for the recruitment of polymorphonuclear cells (PMN) to the clearance of apoptotic cells. Autoantibodies decorating secondary necrotic cells (SNEC) induce proinflammatory responses after activation of blood-borne phagocytes. Analysing the sialylation status of affinity-purified anti-histone IgG in patients with systemic lupus erythematosus (SLE), we demonstrated that the anti-histone IgG was contained preferentially in the non-sialylated fraction. In functional ex-vivo phagocytosis studies, non-sialylated anti-SNEC IgG directed SNEC preferentially into PMN but did not change their cytokine secretion profiles. In contrast, sialylated IgG reduced the phagocytosis by monocytes of SNEC. Moreover, the sialylated anti-SNEC IgG was not simply anti-inflammatory, but switched the cytokine secretion profiles from interleukin (IL)-6/IL-8 to tumour necrosis factor (TNF)-α/IL-1ß. Here we describe how different sialylation statuses of IgG autoantibodies contribute to the complex inflammatory network that regulates chronic inflammation.


Assuntos
Autoanticorpos/metabolismo , Fragmentos Fc das Imunoglobulinas/metabolismo , Imunoglobulina G/metabolismo , Lúpus Eritematoso Sistêmico/metabolismo , Neutrófilos/metabolismo , Fagocitose , Adulto , Idoso , Idoso de 80 Anos ou mais , Apoptose/imunologia , Autoanticorpos/imunologia , Estudos de Casos e Controles , Regulação da Expressão Gênica , Glicosilação , Histonas/imunologia , Histonas/metabolismo , Humanos , Interleucina-1beta/genética , Interleucina-1beta/imunologia , Interleucina-6/genética , Interleucina-6/imunologia , Interleucina-8/genética , Interleucina-8/imunologia , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/patologia , Pessoa de Meia-Idade , Neutrófilos/imunologia , Neutrófilos/patologia , Cultura Primária de Células , Ácidos Siálicos/metabolismo , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologia
4.
Opt Express ; 24(23): 26503-26514, 2016 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-27857383

RESUMO

In this paper, a detailed description of the optical coupling into a Whispering Gallery Mode (WGM) resonator through a prism via frustrated total internal reflection (FTIR) is presented. The problem is modeled as three media with planar interfaces and closed expressions for FTIR are given. Then, the curvature of the resonator is taken into account and the mode overlap is theoretically studied. A new analytical expression giving the optimal geometry of a disc-shaped or ring-shaped resonator for maximizing the intra-cavity circulating power is presented. Such expression takes into consideration the spatial distribution of the WGM at the surface of the resonator, thus being more accurate than the currently used expressions. It also takes into account the geometry of the prism. It is shown an improvement in the geometry values used with the current expressions of about 30%. The reason why the pump laser signal can be seen in experiments under critical coupling is explained on this basis. Then, the conditions required for exciting the highest possible optical power inside the resonator are obtained. The aim is to achieve a highly-efficient up-conversion of a THz signal into the optical domain via the second-order nonlinearity of the resonator material.

5.
Lupus ; 25(8): 934-42, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27252272

RESUMO

Glycosylation is well-known to modulate the functional capabilities of immunoglobulin G (IgG)-mediated cellular and humoral responses. Indeed, highly sialylated and desialylated IgG is endowed with anti- and pro-inflammatory activities, respectively, whereas fully deglycosylated IgG is a rather lame duck, with no effector function besides toxin neutralization. Recently, several studies revealed the impact of different glycosylation patterns on the Fc part and Fab fragment of IgG in several autoimmune diseases, including systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Here, we provide a synoptic update summarizing the most important aspects of antibody glycosylation, and the current progress in this field. We also discuss the therapeutic options generated by the modification of the glycosylation of IgG in a potential treatment for chronic inflammatory diseases.


Assuntos
Artrite Reumatoide/imunologia , Autoanticorpos/sangue , Fragmentos Fab das Imunoglobulinas/imunologia , Imunoglobulina G/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Glicosilação , Humanos
6.
Clin Exp Immunol ; 179(1): 1-4, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25354655

RESUMO

In an organism, cell death occurs at many different sites and in many different forms. It is frequently part of normal development or serves to maintain cell homeostasis. In other cases, cell death not only occurs due to injury, disease or infection, but also as a consequence of various therapeutic interventions. However, in all of these scenarios, the immune system has to react to the dying and dead cells and decide whether to mount an immune response, to remain quiet or to initiate healing and repopulation. This is essential for the organism, testified by many diseases that are associated with malfunctioning in the cell death process, the corpse removal, or the ensuing immune responsiveness. Therefore, dying cells generally have to be considered as instructors of the immune system. How this happens and which signals and pathways contribute to modulate or shape the immune response is still elusive in many conditions. The articles presented in this Special Issue address such open questions. They highlight that the context in which cell death occurs will not only influence the cell death process itself, but also affect the surrounding cellular milieu, how the generation and presence of 'eat me' signals can have an impact on cell clearance, and that the exact nature of the residual 'debris' and how it is processed are fundamental to determining the immunological consequences. Hopefully, these articles initiate new approaches and new experiments to complete our understanding of how cell death and the immune system interact with each other.


Assuntos
Morte Celular/imunologia , Sistema Imunitário/fisiologia , Humanos
7.
Clin Exp Immunol ; 179(1): 75-84, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24995908

RESUMO

Apoptosis of polymorphonuclear neutrophils (PMN) and subsequent 'silent' removal represents an important check-point for the resolution of inflammation. Failure in PMN clearance resulting in secondary necrosis-driven tissue damage has been implicated in conditions of chronic inflammation and autoimmunity. Apoptotic PMN undergo profound biophysical changes that warrant their efficient recognition and uptake by phagocytes before fading to secondary necrosis. In this study, we demonstrate that staurosporine (STS), a non-selective but potent inhibitor of cyclin-dependent kinase and protein kinase C, exerts a drastic impact on PMN apoptosis. PMN treated with STS underwent an unconventional form of cell death characterized by a delayed exposure of aminophospholipids, including phosphatidylserine (PS) and phosphatidylethanolamine and an increased exposure of neo-glycans. STS caused an impaired cellular fragmentation and accelerated DNA fragmentation. Phagocytosis of STS-treated PMN lacking PS on their surfaces was decreased significantly, which highlights the importance of PS for the clearance of apoptotic PMN. Specific opsonization with immune complexes completely restored phagocytosis of STS-treated PMN, demonstrating the efficiency of back-up clearance pathways in the absence of PS exposure.


Assuntos
Apoptose/imunologia , Neutrófilos/imunologia , Complexo Antígeno-Anticorpo/imunologia , Antígenos de Superfície/metabolismo , Apoptose/efeitos dos fármacos , Células Cultivadas , Fragmentação do DNA/efeitos dos fármacos , Humanos , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Fagocitose/efeitos dos fármacos , Fagocitose/imunologia , Fenótipo , Fosfatidilserinas/farmacologia , Estaurosporina/farmacologia
8.
Clin Exp Immunol ; 179(1): 39-49, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24673456

RESUMO

Most cases of systemic lupus erythematosus (SLE) are characterized by an impaired clearance of apoptotic cells in various tissues. Non-cleared apoptotic waste is considered an immunogen driving the autoimmune response in patients with SLE. During the execution of apoptosis, membrane blebs are formed and filled with cellular components. Here, we evaluate the cytoskeletal pathway(s) responsible for the loading of SLE prototypic nuclear autoantigens into the apoptotic cell-derived membranous vesicles (ACMV) generated during late phases of apoptosis. HeLa cells expressing a fusion protein of histone H2B with green fluorescent protein (GFP) were irradiated with ultraviolet (UV)-B to induce apoptosis. The appearance and trafficking of chromatin-derived material was monitored by fluorescence microscopy. Specific inhibitors of cytoskeletal pathways were employed to identify the motile elements involved in translocation and trafficking of the nuclear components. We observed that immediately after their appearance the ACMV did not contain histone H2B(GFP) ; in this phase the fluorescence was contained in the nuclear remnants and the cytoplasm. Within consecutive minutes the ACMV were loaded with chromatin-derived material, whereas the loading of simultaneously created ACMV with histone H2B(GFP) was not uniform. Some ACMV were preferentially filled and, consequently, showed a remarkably higher histone H2B(GFP) accumulation. Inhibitors of the cytoskeleton revealed that functional microtubules and myosin light chain kinase are required for nuclear shrinkage and loading of nuclear material into the ACMV, respectively.


Assuntos
Apoptose/imunologia , Autoantígenos/imunologia , Micropartículas Derivadas de Células/imunologia , Micropartículas Derivadas de Células/metabolismo , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/metabolismo , Microtúbulos/metabolismo , Quinase de Cadeia Leve de Miosina/metabolismo , Apoptose/efeitos da radiação , Linhagem Celular , Tamanho do Núcleo Celular , Citoesqueleto/metabolismo , Humanos , Modelos Biológicos
9.
Lupus ; 24(6): 569-81, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25389233

RESUMO

In addition to the redundancy of the receptors for the Fc portion of immunoglobulins, glycans result in potential ligands for a plethora of lectin receptors found in immune effector cells. Here we analysed the exposure of glycans containing fucosyl residues and the fucosylated tri-mannose N-type core by complexed native IgG in longitudinal serum samples of well-characterized patients with systemic lupus erythematosus. Consecutive serum samples of a cohort of 15 patients with systemic lupus erythematosus during periods of increased disease activity and remission were analysed. All patients fulfilled the 1982 American College of Rheumatology classification criteria. Sera of 15 sex- and age-matched normal healthy blood donors served as controls. The levels and type of glycosylation of complexed random IgG was measured with lectin enzyme-immunosorbent assays. After specifically gathering IgG complexes from sera, biotinylated lectins Aleuria aurantia lectin and Lens culinaris agglutinin were employed to detect IgG-associated fucosyl residues and the fucosylated tri-mannose N-glycan core, respectively. In sandwich-ELISAs, IgG-associated IgM, IgA, C1q, C3c and C-reactive protein (CRP) were detected as candidates for IgG immune complex constituents. We studied associations of the glycan of complexed IgG and disease activity according to the physician's global assessment of disease activity and the systemic lupus erythematosus disease activity index 2000 documented at the moment of blood taking. Our results showed significantly higher levels of Aleuria aurantia lectin and Lens culinaris agglutinin binding sites exposed on IgG complexes of patients with systemic lupus erythematosus than on those of normal healthy blood donors. Disease activity in systemic lupus erythematosus correlated with higher exposure of Aleuria aurantia lectin-reactive fucosyl residues by immobilized IgG complexes. Top levels of Aleuria aurantia lectin-reactivity were found in samples taken during the highest activity of systemic lupus erythematosus. Our results show that native circulating IgG complexes from active systemic lupus erythematosus patients expose fucosyl residues and their glycan core is accessible to soluble lectins. Two putative mechanisms may contribute to the increased exposure of these glycans: (1) the canonical N-glycosylation site of the IgG-CH2 domain; (2) an IgG binding non-IgG molecule, like complement or C-reactive protein. In both cases the complexed IgG may be alternatively targeted to lectin receptors of effector cells, e.g. dendritic cells.


Assuntos
Complexo Antígeno-Anticorpo/sangue , Complexo Antígeno-Anticorpo/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Lúpus Eritematoso Sistêmico/sangue , Lúpus Eritematoso Sistêmico/imunologia , Adolescente , Adulto , Proteína C-Reativa/metabolismo , Estudos de Coortes , Complemento C1q/imunologia , Proteínas do Sistema Complemento/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Glicosilação , Humanos , Lectinas , Lens (Planta) , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Adulto Jovem
10.
Lupus ; 21(7): 781-3, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22635232

RESUMO

Autoantibodies against opsonins of dying and dead cells mediate Fcγ receptor-dependent phagocytosis of autologous apoptotic and necrotic cells and hereby tend to elicit inflammation instead of silent clearance. We analysed sera of patients with chronic autoimmune diseases for the occurrence of IgG autoantibodies recognizing galectins. These pluripotent effectors can also bind to apoptotic or necrotic cells. Patients with antiphospholipid syndrome (APS; n = 104) and systemic lupus erythematosus (SLE; n = 62) were examined, healthy donors (n = 31) served as controls. Selected peptides of galectin (Gal)-2 were employed for peptide-based ELISAs. Levels of anti-Gal-2(PEP)-IgG were significantly increased in SLE and APS when compared with controls. In addition, patients with APS showed significantly higher levels of anti-Gal-2(PEP)-IgG compared with patients with SLE. Anti-Gal-2(PEP)-IgG may, therefore, be considered novel biomarkers for APS.


Assuntos
Síndrome Antifosfolipídica/imunologia , Autoanticorpos/sangue , Galectina 2/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Adulto , Síndrome Antifosfolipídica/sangue , Biomarcadores/sangue , Estudos de Casos e Controles , Feminino , Humanos , Imunoglobulina G/sangue , Lúpus Eritematoso Sistêmico/sangue , Masculino , Pessoa de Meia-Idade
11.
Z Rheumatol ; 69(2): 152, 154-6, 2010 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-20107814

RESUMO

Systemic lupus erythematosus (SLE) is a complex prototypic autoimmune disease that is based on genetic factors (complement deficiencies) and is influenced by gender (female), environment (infections and UV irradiation), as well as random events (somatic mutations). The course of the disease is influenced by genes (e.g. FcgammaRIIA) and behaviour (sun-exposure). Inefficient clearance of dying cells and subsequent accumulation of apoptotic cell remnants is an intrinsic defect causing the permanent presence of cellular debris responsible for the initiation of autoimmunity. We favour the hypothesis that post-apoptotic debris accumulates in germinal centres, activates complement, and serves as a survival signal for B-cells that had stochastically become autoreactive in the process of somatic hypermutation (etiology). In the presence of autoantibodies against apoptotic cells or adaptor molecules the accumulation of post-apoptotic remnants (SNEC) causes immune complex formation and their pathological elimination, maintaining auto-inflammation. The SLE-type autoimmunity addresses nucleic acid-containing complex antigens (viromimetica). Autoantibody-protein-nucleic-acid complexes are likely to be mistaken for opsonised viruses. As a consequence, the immune system responds with the production of type-I interferons, a hallmark of SLE (pathogenesis). We conclude that the pathogenicity of autoantibodies is strongly increased if autoantigens are accessible and immune complexes are formed, which may be considered a binary pyrogen formed from less pro-inflammatory components. The accessibility of cognate autoantigens is likely to be related to impaired or delayed clearance of apoptotic cells.


Assuntos
Apoptose/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Complexo Antígeno-Anticorpo/imunologia , Autoanticorpos/sangue , Autoantígenos/imunologia , Linfócitos B/imunologia , Estruturas Celulares/imunologia , Ativação do Complemento/imunologia , Feminino , Humanos , Interferon Tipo I/sangue , Masculino , Pirogênios/imunologia , Fatores de Risco , Hipermutação Somática de Imunoglobulina/imunologia
12.
Biochem Biophys Res Commun ; 386(1): 71-6, 2009 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-19501044

RESUMO

BACKGROUND: Extracorporeal photopheresis is a therapy for treatment of autoimmune diseases, cutaneous T-cell lymphoma, organ graft rejection as well as graft-versus-host diseases. The exact mechanism how the combination of 8-methoxypsoralen plus UV-A irradiation (PUVA) acts is still unclear. We investigated the cell death of activated and non-activated lymphocytes after PUVA treatment as well as the rate of released blebs and their antigen composition. RESULTS: In presence of 8-MOP, UV-A light highly significantly increased the cell death of activated lymphocytes. The same was observed to a lesser extent in non-activated cells. Blebs derived from activated lymphocytes after PUVA treatment showed the highest surface exposition of phosphatidylserine. These blebs also displayed a high exposure of the antigens CD5 and CD8 as well as a low exposure of CD28 and CD86. CONCLUSION: PUVA treatment exerts anti-inflammatory effects by inducing apoptosis and apoptotic cell-derived blebs with immune suppressive surface composition.


Assuntos
Apoptose , Linfócitos/efeitos dos fármacos , Linfócitos/efeitos da radiação , Metoxaleno/farmacologia , Fotoferese , Raios Ultravioleta , Antígenos de Superfície/imunologia , Vesícula/imunologia , Células Cultivadas , Humanos , Inflamação/imunologia , Ativação Linfocitária/efeitos dos fármacos , Ativação Linfocitária/efeitos da radiação , Fosfatidilserinas/imunologia
13.
Ann Rheum Dis ; 67(11): 1626-32, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18165321

RESUMO

OBJECTIVE: Accumulation of dying and dead cells is thought to be involved in the etiopathogenesis of systemic lupus erythaematosus (SLE). Clearance has been described mainly for apoptotic cells; however, the knowledge of serum factors participating in the phagocytosis of necrotic cells is limited. PATIENTS AND METHODS: Sera from 18 patients with SLE and 10 normal healthy donors (NHD), and macrophages from 3 NHD were included. Autoantibodies and complement were measured by ELISA and phagocytosis by flow cytometry. Binding of serum IgG to necrotic cells was assessed by flow cytometry and confocal microscopy. RESULTS: Sera from patients with SLE and NHD generally promoted the phagocytosis of necrotic cells by macrophages isolated from NHD. Five independent experiments with macrophages from three different NHD led to similar results. The sera from healthy controls displayed a homogeneous activity, whereas sera from patients with SLE showed a dichotomic behaviour. Only sera containing autoantibodies binding to the surfaces of necrotic cells and sufficient complement showed increased phagocytosis promoting activities. In SLE sera, C4 turned out to be the critical complement component in this process. Sera de-complemented by heat treatment strongly reduced phagocytosis of necrotic cells. CONCLUSIONS: Serum components influence the uptake of necrotic cells by phagocytosis competent macrophages from NHD. Complement is required for this process and autoantibodies binding to the surfaces of necrotic cells additionally promote their phagocytosis.


Assuntos
Autoanticorpos/imunologia , Complemento C4/imunologia , Imunoglobulina G/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Fagocitose/imunologia , Células Cultivadas , Feminino , Temperatura Alta , Humanos , Lúpus Eritematoso Sistêmico/patologia , Masculino , Microscopia Confocal , Necrose/imunologia
14.
Autoimmunity ; 40(4): 337-9, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17516223

RESUMO

In order to asses the role of the soluble mediators of serum from patients with SLE in the apoptotic cell clearance, we measured the in vitro phagocytosis of apoptotic Jurkat cells by normal healthy donor macrophages in the presence of SLE patients' sera. A significant increase of the phagocytic index (NHD = 1.0 +/- 0.3; SLE = 1.9 +/- 0.6; p < 0.01) was to be observed in the presence of serum from patients with SLE. The increased phagocytic index correlated to the anti-dsDNA antibodies titers. We conclude that anti-dsDNA antibodies present in sera of patients with SLE favor the apoptotic cell phagocytosis by opsonization of the target cells. This may represent a deviation of the clearance process towards inflammation and a new pathologic feature of these autoantibodies in SLE.


Assuntos
Anticorpos Antinucleares/imunologia , Apoptose/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Macrófagos/imunologia , Fagocitose/imunologia , Anticorpos Antinucleares/sangue , Humanos , Células Jurkat , Lúpus Eritematoso Sistêmico/sangue
15.
Curr Top Microbiol Immunol ; 305: 161-76, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16724805

RESUMO

Dying cells were basically unnoticed by scientists for a long time and only came back into the spotlight roughly 10 years ago. The process of recognition and uptake of apoptotic and necrotic cells is complex and failures in this process can contribute to the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE). Here, we discuss the recognition and uptake molecules which are involved in an efficient clearance of dying cells in early and late phases of cell death. The exposure of phosphatidylserine (PS) is an early surface change of apoptosing cells recognized by several receptors and adaptor molecules. We demonstrated that dying cells have cell membranes with high lateral mobility of PS, which contribute to their efficient clearance. Changes of the glycoprotein composition of apoptotic cells occur later than the exposure of PS. We further observed that complement binding is an early event in necrosis and a rather late event in apoptosis. Complement, C-reactive protein (CRP), and serum DNase I act as back-up molecules in the clearance process. Finally, we discuss how the accumulation of secondary necrotic cells and cellular debris in the germinal centers of secondary lymph organs can lead to autoimmunity. It is reasonable to argue that clearance defects are major players in the development of autoimmune diseases such as SLE.


Assuntos
Apoptose , Doenças Autoimunes/etiologia , Animais , Autoimunidade , Proteína C-Reativa/fisiologia , Proteínas do Sistema Complemento/fisiologia , Desoxirribonuclease I/fisiologia , Humanos , Glicoproteínas de Membrana/fisiologia , Fosfatidilserinas/fisiologia , Componente Amiloide P Sérico/fisiologia
16.
Curr Dir Autoimmun ; 9: 173-87, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16394661

RESUMO

Systemic lupus erythematosus (SLE) is characterized by a diverse array of autoantibodies, particularly against nuclear antigens, thought to derive from apoptotic and necrotic cells. Impaired clearance functions for dying cells may explain accumulation of apoptotic cells in SLE tissues, and secondary necrosis of these cells may contribute to the chronic inflammation in this disease. The exposure of phosphatidylserine (PS) and altered carbohydrates on dying cells are important recognition signals for macrophages. Furthermore, serum factors such as complement, DNase I, pentraxins (e.g. C-reactive protein) and IgM contribute to efficient opsonization and uptake of apoptotic and necrotic cells. Defects in these factors may impact the development of SLE in humans and mice in a variety of ways. We observed impaired clearance of apoptotic cells in lymph nodes and skin biopsies of humans with lupus, as well as intrinsic defects of macrophages differentiated in vitro from SLE patients' CD34+ stem cells, demonstrating that apoptotic cells are not properly cleared in a subgroup of patients with SLE. This altered mechanism for the clearance of dying cells may represent a central pathogenic process in the development and acceleration of this autoimmune disease.


Assuntos
Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/patologia , Animais , Apoptose , Autoimunidade , Proteína C-Reativa/fisiologia , Proteínas do Sistema Complemento/fisiologia , Desoxirribonuclease I/fisiologia , Humanos , Camundongos , Fagócitos/fisiologia , Fagocitose , Fosfatidilserinas/fisiologia , Componente Amiloide P Sérico/fisiologia , Pele/patologia
17.
Cell Death Differ ; 23(6): 1016-25, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26943324

RESUMO

In this study, we deploy a doxycycline-dependent suicide switch integrated in a tumor challenge model. With this experimental setup, we characterized the immunological consequences of cells dying by four distinct cell death stimuli in vivo. We observed that apoptotic cell death induced by expression of the truncated form of BH3 interacting-domain death agonist (tBid) and a constitutively active form of caspase 3 (revC3), respectively, showed higher immunogenicity than cell death induced by expression of the tuberculosis-necrotizing toxin (TNT). Our data indicate that the early release of ATP induces the silent clearance of dying cells, whereas the simultaneous presence of 'find me' signals and danger-associated molecular patterns (DAMPs) promotes inflammatory reactions and increased immunogenicity. This proposed model is supported by findings showing that the production and release of high concentrations of IL-27 by bone-marrow-derived macrophages (BMDM) is limited to BMDM exposed to those forms of death that simultaneously released ATP and the DAMPs heat-shock protein 90 (HSP90) and high-mobility group box-1 protein (HMGB1). These results demonstrate that the tissue microenvironment generated by dying cells may determine the subsequent immune response.


Assuntos
Apoptose/efeitos dos fármacos , Toxinas Biológicas/metabolismo , Alarminas/metabolismo , Animais , Apoptose/efeitos da radiação , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/genética , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/metabolismo , Caspase 3/metabolismo , Linhagem Celular Tumoral , Citocinas/análise , Doxiciclina/farmacologia , Proteína HMGB1/análise , Interleucina-27/análise , Macrófagos/citologia , Macrófagos/imunologia , Macrófagos/metabolismo , Melanoma Experimental/metabolismo , Melanoma Experimental/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Espécies Reativas de Oxigênio/metabolismo , Baço/citologia , Baço/transplante , Toxinas Biológicas/genética , Transplante Homólogo , Raios Ultravioleta
18.
Surgery ; 129(3): 255-66, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11231453

RESUMO

BACKGROUND: The current study evaluated whether biliary tract obstruction stimulates inducible nitric oxide synthase (iNOS) protein expression in the liver and analyzed the implication of lymphomononuclear cells and interleukin-4 (IL-4). METHODS: Male Wistar rats were used. Bile flow interruption was achieved by a complete division of the extrapancreatic common bile duct. iNOS expression was determined by both the Western blot technique and immunohistochemistry. RESULTS: iNOS protein was markedly expressed in the liver 7 days after bile duct obstruction. Treatment with thymostimulin (TP-1), a partially purified thymic extract, reduced the intensity of the expression of iNOS protein in the liver after bile duct ligation. Recent data have suggested that IL-4 attenuates iNOS protein expression. We then analyzed the involvement of this anti-inflammatory cytokine on the modulation of iNOS expression in the liver. The liver from rats that underwent bile duct ligation (BDL) showed a lower content of IL-4 than that of sham-operated (SO) rats. TP-1 treatment increased the content of IL-4 in the liver. Liver slices incubated in vitro with Escherichia coli lipopolysaccharide (LPS, 10 microg/mL) stimulated the expression of iNOS protein. The level of LPS-induced iNOS expression was reduced by lymphomononuclear cells obtained from sham-operated animals. However, lymphomononuclear cells isolated from BDL rats potentiated the induction of iNOS expression by LPS-stimulated liver. However, lymphomononuclear cells from TP-1-treated BDL rats failed to modify LPS-stimulated iNOS expression. The different effect of lymphomononuclear cells on the modulation of iNOS expression in the liver was associated with their ability to generate IL-4. CONCLUSIONS: The liver of jaundiced rats markedly expressed iNOS protein, which was associated to modifications in the content of IL-4 in the liver. Furthermore, lymphomononuclear cells modulate iNOS protein expression in the liver by a mechanism in which IL-4 is involved.


Assuntos
Colestase/enzimologia , Leucócitos Mononucleares/fisiologia , Fígado/enzimologia , Óxido Nítrico Sintase/metabolismo , Animais , Ductos Biliares , Interleucina-4/metabolismo , Ligadura , Fígado/metabolismo , Masculino , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II , Ratos , Ratos Wistar , Extratos do Timo/farmacologia
19.
Arch Med Res ; 23(2): 251-3, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1340306

RESUMO

A retrospective analysis of 140 cases with amebic liver abscess (ALA) seen at the AUNL University Hospital was done to see if patients with complications can be identified earlier in order to decrease morbidity and mortality. Sixteen patients (11.4%) presented complications and six patients died (4.2%). Patients with complications presented jaundice, large or multiple abscesses, acute abdomen, liver failure and sepsis more often than patients without complications. Hemoglobin, hematocrit, prothrombin time, total proteins, albumin, LDH, and BUN were more altered in patients who presented complications. The titer of antibodies against E. histolytica was higher in this group of patients. The six patients who died had been operated on. The causes of death were septic shock in two, sepsis in one, peritonitis in one, liver failure in one and colon perforation in one patient. Pleural effusion, jaundice and acute abdomen were seen in three patients, respectively (50%), two cases had multiple abscesses (33.3%), one patient had a ruptured abscess (16.7%). Patients who died exhibited more alterations in six laboratory examinations at admission: partial prothrombin time, total bilirubin, albumin, BUN, LDH, and leukocytes. Clinical data together with the severe alterations in laboratory examinations at admission for patients with ALA should alert the clinician to suspect complications earlier in order to decrease morbidity and mortality.


Assuntos
Abscesso Hepático Amebiano/complicações , Abdome Agudo/diagnóstico , Abdome Agudo/etiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Anticorpos Antiprotozoários/sangue , Biomarcadores/sangue , Criança , Pré-Escolar , Entamoeba histolytica/imunologia , Feminino , Humanos , Icterícia/diagnóstico , Icterícia/etiologia , Abscesso Hepático Amebiano/sangue , Abscesso Hepático Amebiano/tratamento farmacológico , Abscesso Hepático Amebiano/epidemiologia , Abscesso Hepático Amebiano/cirurgia , Falência Hepática/diagnóstico , Falência Hepática/etiologia , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Derrame Pleural/diagnóstico , Derrame Pleural/etiologia , Complicações Pós-Operatórias/mortalidade , Prevalência , Estudos Retrospectivos , Sepse/diagnóstico , Sepse/etiologia
20.
Rev Gastroenterol Mex ; 58(2): 164-9, 1993.
Artigo em Espanhol | MEDLINE | ID: mdl-7747027

RESUMO

The mechanism of production of autoimmune diseases is a loss of tolerance to autoantigens, which in turn produces a destruction of target organs. We review two autoimmune liver diseases which are non-organ specific: autoimmune chronic active hepatitis and primary biliary cirrhosis. The former is classified in three types according to its' profile of autoantibodies: type 1, in which anti smooth muscle and antinuclear autoantibodies are found in high titers; type 2, is characterized by the presence in serum of anti liver/kidney and anti cytosolic 1 autoantibodies; in type 3 anti soluble liver antigen antibody is present, results in this last type of autoimmune hepatitis await confirmation. In primary biliary cirrhosis the most important advance in the serologic diagnosis has been in the classification of anti mitochondrial antibodies. Up to now 9 different types of these antibodies are known, 4 of which are found in this disease: anti M2, anti M4, anti M8 and anti M9. Anti M2 and/or anti M9 are associated with a benign course of the disease, whereas anti M2, anti M8 and anti M8 are associated with a progressive course.


Assuntos
Doenças Autoimunes/diagnóstico , Hepatopatias/diagnóstico , Autoanticorpos/sangue , Hepatite Crônica/diagnóstico , Humanos , Testes Imunológicos , Cirrose Hepática Biliar/diagnóstico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA