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1.
Nat Immunol ; 13(9): 851-6, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22820602

RESUMO

Glycolipids presented by the major histocompatibility complex (MHC) class I homolog CD1d are recognized by natural killer T cells (NKT cells) characterized by either a semi-invariant T cell antigen receptor (TCR) repertoire (type I NKT cells or iNKT cells) or a relatively variable TCR repertoire (type II NKT cells). Here we describe the structure of a type II NKT cell TCR in complex with CD1d-lysosulfatide. Both TCR α-chains and TCR ß-chains made contact with the CD1d molecule with a diagonal footprint, typical of MHC-TCR interactions, whereas the antigen was recognized exclusively with a single TCR chain, similar to the iNKT cell TCR. Type II NKT cell TCRs, therefore, recognize CD1d-sulfatide complexes by a distinct recognition mechanism characterized by the TCR-binding features of both iNKT cells and conventional peptide-reactive T cells.


Assuntos
Apresentação de Antígeno/imunologia , Autoantígenos/imunologia , Células Matadoras Naturais/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/química , Subpopulações de Linfócitos T/imunologia , Animais , Antígenos CD1d/química , Antígenos CD1d/imunologia , Cristalização , Humanos , Células Matadoras Naturais/química , Camundongos , Estrutura Quaternária de Proteína , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Sulfoglicoesfingolipídeos/imunologia , Ressonância de Plasmônio de Superfície , Subpopulações de Linfócitos T/química
2.
Nat Immunol ; 13(9): 857-63, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22820603

RESUMO

Natural killer T cells (NKT cells) are divided into type I and type II subsets on the basis of differences in their T cell antigen receptor (TCR) repertoire and CD1d-antigen specificity. Although the mode by which type I NKT cell TCRs recognize CD1d-antigen has been established, how type II NKT cell TCRs engage CD1d-antigen is unknown. Here we provide a basis for how a type II NKT cell TCR, XV19, recognized CD1d-sulfatide. The XV19 TCR bound orthogonally above the A' pocket of CD1d, in contrast to the parallel docking of type I NKT cell TCRs over the F' pocket of CD1d. At the XV19 TCR-CD1d-sulfatide interface, the TCRα and TCRß chains sat centrally on CD1d, where the malleable CDR3 loops dominated interactions with CD1d-sulfatide. Accordingly, we highlight the diverse mechanisms by which NKT cell TCRs can bind CD1d and account for the distinct antigen specificity of type II NKT cells.


Assuntos
Antígenos CD1d/imunologia , Células Matadoras Naturais/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/química , Sulfoglicoesfingolipídeos/imunologia , Subpopulações de Linfócitos T/imunologia , Animais , Antígenos CD1d/química , Cristalização , Células Matadoras Naturais/química , Ativação Linfocitária , Camundongos , Reação em Cadeia da Polimerase , Estrutura Quaternária de Proteína , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Sulfoglicoesfingolipídeos/química , Ressonância de Plasmônio de Superfície , Subpopulações de Linfócitos T/química
3.
BMC Pediatr ; 24(1): 414, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38926645

RESUMO

BACKGROUND: Guillain‒Barre syndrome (GBS) is an acute inflammatory peripheral neuropathy caused by autoimmunity. Gangliosides and sulfatides are important components of peripheral nerves. Anti-sulfatide antibody-mediated complement is associated with acute sensorimotor peripheral neuropathy in GBS, which is characterized by pain and paresthesias. CASE PRESENTATION: The child was a 7-year-old girl with headache and abdominal pain, followed by limb numbness and pain. Cranial imaging showed ventricular dilatation, peripheral nerve function conduction examination showed polyradiculopathy, and cerebrospinal fluid tests showed normal cell counts but elevated protein levels, all of which led to the diagnosis of GBS. After treatment with intravenous immunoglobulin (400 mg/kg × 5 days), the symptoms did not improve, and muscle strength progressively worsened, accompanied by paroxysmal complexion flushing, heart rate fluctuation, hyperhidrosis, and a progressive increase in cerebrospinal fluid protein (up to 3780.1 mg/L). On the basis of these findings combined with serum anti-sulfatide IgM positivity, anti-sulfatide antibody-related GBS was considered, and treatment with low-dose prednisolone (1 mg/kg/d) led to symptom improvement. CONCLUSIONS: Anti-sulfatide antibody-associated GBS is associated with small fiber peripheral neuropathy. The main manifestations are pain, paresthesias and autonomic dysfunction. In addition to the dysfunction of spinal nerve root absorption caused by increased cerebrospinal fluid protein, autonomic dysfunction may be involved in pain. When the therapeutic effect of immunoglobulin is not satisfactory, a low dose and short course of corticosteroids can be considered, and the prognosis is good.


Assuntos
Dor Abdominal , Síndrome de Guillain-Barré , Cefaleia , Sulfoglicoesfingolipídeos , Humanos , Feminino , Criança , Síndrome de Guillain-Barré/diagnóstico , Síndrome de Guillain-Barré/tratamento farmacológico , Dor Abdominal/etiologia , Cefaleia/etiologia , Cefaleia/tratamento farmacológico , Sulfoglicoesfingolipídeos/imunologia , Autoanticorpos/sangue , Prednisolona/uso terapêutico
5.
J Immunol ; 199(1): 97-106, 2017 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-28526683

RESUMO

Invariant NKT (iNKT) cells are innate-like lymphocytes that recognize lipid Ags presented by CD1d. The prototypical Ag, α-galactosylceramide, strongly activates human and mouse iNKT cells, leading to the assumption that iNKT cell physiology in human and mouse is similar. In this article, we report the surprising finding that human, but not mouse, iNKT cells directly recognize myelin-derived sulfatide presented by CD1d. We propose that sulfatide is recognized only by human iNKT cells because of the unique positioning of the 3-O-sulfated ß-galactose headgroup. Surface plasmon resonance shows that the affinity of human CD1d-sulfatide for the iNKT cell receptor is relatively low compared with CD1d-α-galactosylceramide (KD of 19-26 µM versus 1 µM). Apolipoprotein E isolated from human cerebrospinal fluid carries sulfatide that can be captured by APCs and presented by CD1d to iNKT cells. APCs from patients with metachromatic leukodystrophy, who accumulate sulfatides due to a deficiency in arylsulfatase-A, directly activate iNKT cells. Thus, we have identified sulfatide as a self-lipid recognized by human iNKT cells and propose that sulfatide recognition by innate T cells may be an important pathologic feature of neuroinflammatory disease and that sulfatide in APCs may contribute to the endogenous pathway of iNKT cell activation.


Assuntos
Apresentação de Antígeno , Ativação Linfocitária , Células T Matadoras Naturais/imunologia , Sulfoglicoesfingolipídeos/imunologia , Animais , Antígenos CD1d/imunologia , Apolipoproteínas E/líquido cefalorraquidiano , Apolipoproteínas E/química , Apolipoproteínas E/imunologia , Linhagem Celular , Cerebrosídeo Sulfatase/deficiência , Cerebrosídeo Sulfatase/metabolismo , Galactosilceramidas/imunologia , Humanos , Leucodistrofia Metacromática/imunologia , Camundongos , Células T Matadoras Naturais/fisiologia , Receptores de Antígenos de Linfócitos T/imunologia , Ressonância de Plasmônio de Superfície , Subpopulações de Linfócitos T/imunologia
6.
Eur J Neurol ; 24(11): 1334-1340, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28782863

RESUMO

BACKGROUND AND PURPOSE: Anti-sulfatide antibodies have been observed in heterogeneous neuropathies and their clinical relevance is still controversial. Whether the combination of sulfatide with galactocerebroside would increase sensitivity or specificity of enzyme-linked immunosorbent assay testing compared to sulfatide alone was assessed. METHODS: Immunoglobulin M (IgM) antibodies to sulfatides, galactocerebroside and combined sulfatide and galactocerebroside (Sulf/GalC) were measured in 229 neuropathy patients, including 73 with IgM paraproteinemic neuropathy [62 with anti-myelin-associated glycoprotein (anti-MAG) antibody] and 156 with other neuropathies. Results from 27 patients with IgM monoclonal gammopathy without neuropathy and 28 healthy subjects served as control. RESULTS: Thirty-three patients showed increased titers of anti-sulfatide antibodies, 28 of whom had an IgM paraproteinemic neuropathy (P < 0.0001). When evaluating the reactivity for the combination Sulf/GalC, 57/229 patients were found to be positive, including 36/73 (49%) with IgM paraproteinemic neuropathy (P < 0.0001). Patients with known anti-sulfatide antibodies also showed anti-Sulf/GalC reactivity, with increased titers in 48.5% of the cases. Testing for anti-Sulf/GalC antibodies allowed 24 additional patients to be detected (eight with IgM paraproteinemic neuropathies), who had no reactivity to the individual glycolipids. Amongst the 11 subjects with IgM paraproteinemic neuropathy who were negative for anti-MAG antibodies, only two were reactive to sulfatide, whilst six (55%) were found to be positive when tested against the combination of sulfatide and galactocerebroside. CONCLUSIONS: Testing for both sulfatide and galactocerebroside in IgM paraproteinemic neuropathies seems to increase the sensitivity compared to anti-sulfatide antibodies alone (49% and 39%, respectively, with a slightly reduced specificity, from 97% to 87%), helping the characterization of otherwise undefined neuropathy that could benefit from immunomodulatory therapy.


Assuntos
Autoanticorpos/análise , Galactosilceramidas/imunologia , Imunoglobulina M/imunologia , Doenças do Sistema Nervoso Periférico/imunologia , Sulfoglicoesfingolipídeos/imunologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Glicoproteína Associada a Mielina/imunologia , Adulto Jovem
7.
Scand J Gastroenterol ; 52(4): 409-413, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27908207

RESUMO

OBJECTIVE: To explore a possible significance of the presence of anti-ganglioside and anti-sulfatide antibodies in sera of adult patients with celiac disease (CD) in different clinical scenario. METHODS: We selected 22 adult patients with newly diagnosed CD and 20 age-sex matched non-CD controls. Patients' serum was tested - before and after at least 6 months on a gluten-free diet (GFD) - for anti-GM1, GM2, GM3, GD1a, GD1b, GD3, GT1a, GT1b, GQ1b and sulfatide IgM, IgG and IgA auto-antibodies, by means of a dot blot technique and enzyme-linked immunosorbent assay (ELISA). RESULTS: We found the presence of auto-antibodies in untreated patients. In particular, anti-sulfatide IgG antibodies were present in 8 (36%) patients independently of the presence of neurological symptoms. Anti-sulfatide IgA antibodies were present in 3 (19%) patients. During GFD, anti-sulfatide IgG disappeared in all the patients, whereas IgA were observed in 2 patients. Anti-sulfatide, anti-GM1 and anti-GM2 IgM antibodies were also observed in 2 patients on a GFD. All the other auto-antibodies were absent and no demographic or clinical parameters were associated. Non-CD controls did not present any auto-antibody. CONCLUSIONS: We found anti-sulfatide IgG antibodies in CD patients on a gluten-containing diet. Anti-sulfatide IgA antibodies persisted during GFD together with the occurrence of other IgM auto-antibodies. These data suggest a possible link between gluten and IgG auto-antibodies.


Assuntos
Autoanticorpos/sangue , Doença Celíaca/sangue , Gangliosídeos/imunologia , Isotipos de Imunoglobulinas/sangue , Sulfoglicoesfingolipídeos/imunologia , Adulto , Idoso , Estudos de Casos e Controles , Doença Celíaca/dietoterapia , Doença Celíaca/imunologia , Dieta Livre de Glúten , Ensaio de Imunoadsorção Enzimática , Feminino , Glutens/efeitos adversos , Humanos , Immunoblotting , Itália , Masculino , Pessoa de Meia-Idade
8.
Neurochem Res ; 41(1-2): 130-43, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26542149

RESUMO

Sulfatide (3-O-sulfogalactosylceramide, SM4s) was isolated by Thudichum from the human brain in 1884. Together with galactosylceramide, its direct metabolic precursor in the biosynthetic pathway, sulfatide is highly enriched in myelin in the central and peripheral nervous system, and it has been implicated in several aspects of the biology of myelin-forming cells. Studies obtained using galactolipid-deficient mice strongly support the notion that sulfatide plays critical roles in the correct structure and function of myelin membrane. A number of papers are suggesting that these roles are mediated by a specific function of sulfatide in the lateral organization of myelin membrane, thus affecting the sorting, lateral assembly, membrane dynamics and also the function of specific myelin proteins in different substructures of the myelin sheath. The consequences of altered sulfatide metabolism and sulfatide-mediated myelin organization with respect to myelin diseases are still poorly understood, but it's very likely that sulfatide might represent not only a critical player in the pathogenesis of several diseases, including multiple sclerosis and Alzheimer's disease, but also a potentially promising therapeutic target.


Assuntos
Bainha de Mielina/metabolismo , Sulfoglicoesfingolipídeos/farmacologia , Animais , Anticorpos/imunologia , Humanos , Camundongos , Sulfoglicoesfingolipídeos/imunologia
9.
Eur J Neurol ; 22(5): 879-82, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25597226

RESUMO

BACKGROUND AND PURPOSE: Anti-sulfatide immunoglobulin M (IgM) antibodies have been associated with different forms of neuropathies but their diagnostic role in neuropathy remains unclear. METHODS: The clinical association of increased titers of anti-sulfatide IgM antibodies in 570 patients with neuropathy and related disorders examined in our laboratory since 2004 was reviewed. Sera were tested by enzyme-linked immunosorbent assay at the initial serum dilution of 1:32,000 and titrated by serial two-fold dilution. In all positive patients IgM antibodies to myelin-associated glycoprotein (MAG) were also measured by western blot. RESULTS: High titers of anti-sulfatide antibodies were found in 39 patients including 33 (85%) who also had anti-MAG IgM. Six patients did not have anti-MAG IgM including five in whom moderately increased anti-sulfatide titers were associated with different forms of neuropathy. One patient with a demyelinating neuropathy and IgM monoclonal gammopathy had markedly increased anti-sulfatide titers (1:256,000). CONCLUSIONS: Increased titers of anti-sulfatide IgM antibodies are not infrequent in patients with neuropathy where they are often associated with a concomitant reactivity to MAG. A selective reactivity to sulfatide, however, is rarely found and is associated with different forms of neuropathy limiting its usefulness in the diagnosis of neuropathy.


Assuntos
Anticorpos/sangue , Imunoglobulina M/imunologia , Doenças do Sistema Nervoso Periférico/imunologia , Sulfoglicoesfingolipídeos/imunologia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Glicoproteína Associada a Mielina/imunologia
10.
Front Immunol ; 15: 1358886, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38660303

RESUMO

Background: Bickerstaff brainstem encephalitis (BBE) is a rare disease considered caused by acute demyelination of the brainstem, most often resulting from secondary autoimmune responses. To our knowledge, this is the first probable case report of shingles-associated BBE with anti-sulfatide IgM positivity. Case presentation: We report the case of an 83-year-old woman with symptoms of progressive limb weakness, difficulty swallowing food, and disturbed consciousness that occurred 4 weeks following herpes zoster infection. Autoimmune anti-sulfatide antibodies were positive and fluid-attenuated inversion recovery (FLAIR) sequences revealed clear high signal intensity in pons and bilateral thalamus. Our patient's condition improved markedly with glucocorticoid treatment. After 2 months of treatment, our patient was fully recovered. We considered that for her case, BBE is the most appropriate diagnosis. Conclusions: We emphasize the importance of a careful medical history and assessment of clinical symptoms, performing MRI, testing autoimmune antibodies for rapid diagnosis, and ruling out differential diagnoses. Further studies involving more patients with BBE with IgM anti-sulfatide autoantibodies will increase the understanding of the clinical characteristics and advance the diagnosis and treatment of this syndrome. Meanwhile, it is crucial for dermatologists to know about this severe neurological complication following shingles.


Assuntos
Autoanticorpos , Tronco Encefálico , Encefalite , Imunoglobulina M , Sulfoglicoesfingolipídeos , Humanos , Feminino , Tronco Encefálico/imunologia , Idoso de 80 Anos ou mais , Imunoglobulina M/imunologia , Imunoglobulina M/sangue , Autoanticorpos/imunologia , Autoanticorpos/sangue , Encefalite/diagnóstico , Encefalite/imunologia , Encefalite/tratamento farmacológico , Sulfoglicoesfingolipídeos/imunologia , Imageamento por Ressonância Magnética , Glucocorticoides/uso terapêutico
11.
J Neurochem ; 127(5): 600-4, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23777394

RESUMO

Multiple sclerosis (MS) is considered an autoimmune demyelinating disease of the CNS and myelin-derived glycolipids are one of the targets of this autoimmune attack. In this study, we examined for the first time the plasma distribution of sulfatide isoforms. Sulfatides with long-chain (C24 : 0 or C24 : 1) and short-chain (C16 : 0 or C18 : 0) fatty acids were quantified in plasma of relapsing­remitting MS patients by ultra-high-performance liquid chromatography tandem mass spectrometry. We found that C18 : 0 and C24 : 1 sulfatide plasma levels positively correlated with the Expanded Disability Status Scale. C16/C18 : 0 and C16/C24 : 0 ratios also correlated with the age and the time since last relapse. Healthy women showed higher levels of C16 : 0 sulfatide than healthy men; however, this gender difference disappeared in MS patients. Our data underline the potential use of sulfatides as biomarkers in relapsing­remitting MS and points to a possible association with the higher susceptibility of women to develop MS.Sulfatides are glycolipids highly enriched in myelin that have been associated with multiple sclerosis (MS). In this study, we have found a positive correlation between levels of specific sulfatides in plasma and increased disability in patients with relapsing-remitting MS. These findings underline the potential use of these molecules as biomarkers for MS.


Assuntos
Autoimunidade/imunologia , Esclerose Múltipla Recidivante-Remitente/imunologia , Esclerose Múltipla Recidivante-Remitente/metabolismo , Sulfoglicoesfingolipídeos/sangue , Adulto , Biomarcadores/sangue , Cromatografia Líquida , Feminino , Humanos , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Peso Molecular , Esclerose Múltipla Recidivante-Remitente/epidemiologia , Fatores de Risco , Sulfoglicoesfingolipídeos/química , Sulfoglicoesfingolipídeos/imunologia , Adulto Jovem
12.
Eur J Immunol ; 42(9): 2505-10, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22829134

RESUMO

αß T-cell lines specific for sulfatide, an abundant myelin glycosphingolipid presented by various CD1 molecules, have been previously derived from PBMCs of patients with demyelinating diseases such as multiple sclerosis (MS) but also from healthy subjects. Using an unbiased tetramer-based MACS enrichment method to enrich for rare antigen-specific cells, we confirmed the presence of CD1d-sulfatide-specific T cells in all healthy individuals examined. Surprisingly, the great majority of fresh sulfatide-specific T cells belonged to the γδ lineage. Furthermore, these cells used the Vδ1 TCR variable segment, which is uncommon in the blood but predominates in tissues such as the gut and specifically accumulates in MS lesions. Recombinant Vδ1 TCRs from different individuals were shown to bind recombinant CD1d-sulfatide complexes in a sulfatide-specific manner. These results provide the first direct demonstration of MHC-like-restricted, antigen-specific recognition by γδ TCRs. Together with previous reports, they support the notion that human Vδ1 T cells are enriched in CD1-specific T cells and suggest that the Vδ1 T-cell population that accumulates in MS lesions might be enriched in CD1-sulfatide-specific cells.


Assuntos
Antígenos CD1d/imunologia , Epitopos de Linfócito T/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Sulfoglicoesfingolipídeos/imunologia , Linfócitos T/imunologia , Antígenos/imunologia , Genes MHC Classe I/imunologia , Humanos , Esclerose Múltipla/imunologia
13.
Eur J Immunol ; 42(11): 2851-60, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22777932

RESUMO

Sulfatide-reactive CD1d-restricted natural killer T (NKT) lymphocytes belong to the type II NKT cell subset with diverse TCRs, and have been found to regulate experimental auto-immune encephalomyelitis, tumor immunity, and experimental hepatitis in murine models. NKT cells can be activated by self-lipids presented by CD1d, manifested as autoreactivity. The identity of most of these self-lipids remains unknown. By isolating lipids from a CD1d-expressing, highly stimulatory antigen presenting cell, we identified isoforms of ß-glucosylceramide (GlcCer), with sphingosine and fatty acid chain lengths of C24:0 and C16:0, that activated a sulfatide-reactive type II NKT cell hybridoma. A screen of structurally related glycosphingolipids demonstrated ß-galactosylceramide (GalCer) as another ligand, and further, that the lysoforms were the most potent isoform of the glycosphingo-lipid ligands, followed by isoforms with a long fatty acid chain of C24. Thus, the same type II NKT cell was activated by several ligands, namely sulfatide, GlcCer, and GalCer. However, CD1d-dependent reactivity to antigen presenting cells lacking all GlcCer-based glycosphingolipids, or all glycosphingolipids, was maintained. This suggests that other endogenous, nonglycosphingolipid, lipid ligands contribute to steady-state autoreactivity by type II NKT cells.


Assuntos
Antígenos CD1d/imunologia , Galactosilceramidas/imunologia , Glucosilceramidas/imunologia , Células T Matadoras Naturais/imunologia , Sulfoglicoesfingolipídeos/imunologia , Animais , Feminino , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Organismos Livres de Patógenos Específicos , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
14.
Glycoconj J ; 30(9): 819-23, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23877649

RESUMO

The association of sulfatide with specific proteins in oligodendrocytes was examined by co-immunoprecipitation with an anti-sulfatide antibody. Protein kinase activity was detected in precipitates with a monoclonal antibody to sulfatide (O4) from the rat primary immature oligodendrocytes. We conducted in vitro kinase assay of tyrosine phosphorylated proteins of 80, 59, 56, 53 and 40 kDa by gel electrophoresis. Of these proteins, the proteins of 59 kDa and 53/56 kDa were identified as the Src family tyrosine kinases Fyn and Lyn on the basis of their sequential immunoprecipitation with anti-Fyn and anti-Lyn antibodies, respectively. The 40 kDa protein was identified as the α subunit of the heterotrimeric G protein. These observations suggest that O4 immunoprecipitates sulfatide rafts including Fyn, Lyn and the α subunit of the heterotrimeric G protein.


Assuntos
Subunidades alfa de Proteínas de Ligação ao GTP/imunologia , Oligodendroglia/imunologia , Proteínas Proto-Oncogênicas c-fyn/imunologia , Sulfoglicoesfingolipídeos/imunologia , Quinases da Família src/imunologia , Animais , Anticorpos Monoclonais/imunologia , Células Cultivadas , Subunidades alfa de Proteínas de Ligação ao GTP/metabolismo , Microdomínios da Membrana/imunologia , Microdomínios da Membrana/metabolismo , Oligodendroglia/metabolismo , Ligação Proteica , Proteínas Proto-Oncogênicas c-fyn/metabolismo , Ratos , Sulfoglicoesfingolipídeos/metabolismo , Quinases da Família src/metabolismo
15.
J Neurosci ; 31(17): 6481-92, 2011 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-21525289

RESUMO

CNS myelin is strongly inhibitory to growing axons and is thought to be a major contributor to CNS axon regenerative failure. Although a number of proteins present in myelin, including Nogo, MAG, and oligodendrocyte-myelin glycoprotein (OMgp), have been identified as myelin-associated inhibitors, studies of mice lacking these genes suggest that additional inhibitors present in CNS myelin remain to be identified. Here we have investigated the hypothesis that myelin lipids contribute to CNS regenerative failure. We identified sulfatide, a major constituent of CNS myelin, as a novel myelin-associated inhibitor of neurite outgrowth. Sulfatide, but not galactocerebroside or ceramide, strongly inhibited the neurite outgrowth of retinal ganglion cells (RGCs) when used as a purified lipid substrate. The mechanism involved in sulfatide-mediated inhibition may share features with other known inhibitors, because the Rho inhibitor C3 transferase lessened these effects. Myelin in which sulfatide was lacking or blocked using specific antibodies was significantly less inhibitory to RGC neurite outgrowth in vitro than was wild-type myelin, indicating that sulfatide is a major component of the inhibitory activity of CNS myelin. Mice unable to make sulfatide did not regenerate RGC axons more robustly after optic nerve crush than wild-type littermates under normal conditions but did exhibit a small but significant enhancement in the extent of zymosan-induced regeneration. These results demonstrate that specific lipids can powerfully inhibit axon growth, identify sulfatide as a novel myelin-associated axon growth inhibitor, and provide evidence that sulfatide inhibition contributes to axon regenerative failure in vivo.


Assuntos
Axônios/efeitos dos fármacos , Proteínas da Mielina/antagonistas & inibidores , Regeneração Nervosa/efeitos dos fármacos , Inibição Neural/efeitos dos fármacos , Células Ganglionares da Retina/citologia , Sulfoglicoesfingolipídeos/farmacologia , Animais , Animais Recém-Nascidos , Anticorpos/sangue , Axônios/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Doenças do Sistema Nervoso Central/tratamento farmacológico , Modelos Animais de Doenças , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Biológicos , Proteínas da Mielina/metabolismo , Traumatismos do Nervo Óptico/tratamento farmacológico , Traumatismos do Nervo Óptico/patologia , Traumatismos do Nervo Óptico/fisiopatologia , Ratos , Ratos Sprague-Dawley , Células Ganglionares da Retina/efeitos dos fármacos , Sulfoglicoesfingolipídeos/imunologia , Sulfotransferases/deficiência , Sulfurtransferases/genética , Transfecção/métodos , Zimosan/uso terapêutico , Proteína rhoA de Ligação ao GTP/metabolismo
16.
Parasite Immunol ; 34(11): 499-510, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22738032

RESUMO

Sulphoglycosphingolipids, present on the surface of diverse cells, participate in the regulation of various cellular events. However, little is known about the structure and the role of sulphoglycosphingolipids in trypanosomatids. Herein, sulphated dihexosylceramide structures - composed mainly of sphingosine as the long chain base acylated with stearic acid - have been determined for the first time in Trypanosoma cruzi epimastigotes by UV-MALDI-TOF-MS analysis. Interestingly, inhibition ELISA assays using cruzipain as antigen and polyclonal rabbit antibodies specific for cruzipain, the major cysteine proteinase of T. cruzi, or for its C-terminal domain, have demonstrated (i) that sulphate epitopes are shared between cruzipain and sulphatides of T. cruzi, (ii) that cross-reactivity maps to the C-terminal domain and (iii) the existence of other antigenic determinants in the glycolipidic structures. These features provide evidence that sulphate groups are antigenic in sulphate-containing parasite glycoconjugates. Furthermore, IgG2 antibody levels inversely correlate with disease severity in chronic Chagas disease patients, suggesting that IgG2 antibodies specific for sulphated epitopes might be associated with protective immunity and might be considered as potential surrogates of the course of chronic Chagas disease.


Assuntos
Glicoconjugados/análise , Glicoconjugados/imunologia , Sulfoglicoesfingolipídeos/análise , Sulfoglicoesfingolipídeos/imunologia , Trypanosoma cruzi/química , Trypanosoma cruzi/imunologia , Adulto , Animais , Antiprotozoários/sangue , Doença de Chagas/imunologia , Reações Cruzadas , Cisteína Endopeptidases/química , Cisteína Endopeptidases/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Proteínas de Protozoários , Coelhos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
17.
J Immunol ; 184(3): 1235-41, 2010 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-20026739

RESUMO

A major step in understanding differences in the nature of Ag presentation was the realization that MHC class I samples peptides transported to the endoplasmic reticulum from the cytosol, whereas MHC class II samples peptides from lysosomes. In contrast to MHC class I and II molecules that present protein Ags, CD1 molecules present lipid Ags for recognition by specific T cells. Each of the five members of the CD1 family (CD1a-e) localizes to a distinct subcompartment of endosomes. Accordingly, it has been widely assumed that the distinct trafficking of CD1 isoforms must also have evolved to enable them to sample lipid Ags that traffic via different routes. Among the CD1 isoforms, CD1a is unusual because it does not have a tyrosine-based cytoplasmic sorting motif and uniquely localizes to the early endocytic recycling compartment. This led us to predict that CD1a might have evolved to focus on lipids that localize to early endocytic/recycling compartments. Strikingly, we found that the glycolipid Ag sulfatide also localized almost exclusively to early endocytic and recycling compartments. Consistent with colocalization of CD1a and sulfatide, wild-type CD1a molecules efficiently presented sulfatide to CD1a-restricted, sulfatide-specific T cells. In contrast, CD1a:CD1b tail chimeras, that retain the same Ag-binding capacity as CD1a but traffic based on the cytoplasmic tail of CD1b to lysosomes, failed to present sulfatide efficiently. Thus, the intracellular trafficking route of CD1a is essential for efficient presentation of lipid Ags that traffic through the early endocytic and recycling pathways.


Assuntos
Apresentação de Antígeno/imunologia , Antígenos CD1/metabolismo , Movimento Celular/imunologia , Lipopolissacarídeos/imunologia , Sulfoglicoesfingolipídeos/imunologia , Animais , Antígenos CD1/genética , Bovinos , Movimento Celular/genética , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Endocitose/genética , Endocitose/imunologia , Células HeLa , Humanos , Lipopolissacarídeos/genética , Lipopolissacarídeos/metabolismo , Lisossomos/genética , Lisossomos/imunologia , Lisossomos/metabolismo , Proteínas Mutantes Quiméricas/imunologia , Proteínas Mutantes Quiméricas/metabolismo , Ligação Proteica/genética , Ligação Proteica/imunologia , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Sulfoglicoesfingolipídeos/metabolismo
18.
J Exp Med ; 202(11): 1517-26, 2005 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-16314439

RESUMO

Sulfatide derived from the myelin stimulates a distinct population of CD1d-restricted natural killer T (NKT) cells. Cis-tetracosenoyl sulfatide is one of the immunodominant species in myelin as identified by proliferation, cytokine secretion, and CD1d tetramer staining. The crystal structure of mouse CD1d in complex with cis-tetracosenoyl sulfatide at 1.9 A resolution reveals that the longer cis-tetracosenoyl fatty acid chain fully occupies the A' pocket of the CD1d binding groove, whereas the sphingosine chain fills up the F' pocket. A precise hydrogen bond network in the center of the binding groove orients and positions the ceramide backbone for insertion of the lipid tails in their respective pockets. The 3'-sulfated galactose headgroup is highly exposed for presentation to the T cell receptor and projects up and away from the binding pocket due to its beta linkage, compared with the more intimate binding of the alpha-glactosyl ceramide headgroup to CD1d. These structure and binding data on sulfatide presentation by CD1d have important implications for the design of therapeutics that target T cells reactive for myelin glycolipids in autoimmune diseases of the central nervous system.


Assuntos
Apresentação de Antígeno , Antígenos CD1/química , Autoimunidade , Bainha de Mielina/química , Sulfoglicoesfingolipídeos/química , Animais , Apresentação de Antígeno/imunologia , Antígenos CD1/imunologia , Antígenos CD1d , Autoimunidade/imunologia , Bovinos , Proliferação de Células , Cristalografia por Raios X , Citocinas/imunologia , Citocinas/metabolismo , Feminino , Galactosilceramidas/química , Galactosilceramidas/imunologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Camundongos , Camundongos Knockout , Bainha de Mielina/imunologia , Estrutura Terciária de Proteína , Sulfoglicoesfingolipídeos/imunologia , Linfócitos T/imunologia , Linfócitos T/metabolismo
19.
J Exp Med ; 195(8): 1013-21, 2002 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-11956292

RESUMO

Five CD1 molecules are expressed in humans and it is unclear whether they have specialized or redundant functions. We found that sulfatide is a promiscuous CD1-binding ligand and have isolated T cell clones that are specific for sulfatide and restricted by distinct CD1 molecules. These clones have been used to compare the capacity of different CD1 to present the same glycolipid, to induce effector functions, and to form persistent immunogenic complexes. CD1a, CD1b, and CD1c molecules similarly load sulfatide on the cell surface without processing, and prime Th1 and Th2 responses. Stimulation by sulfatide-loaded CD1a persists much longer than that by CD1b and CD1c in living cells. Use of recombinant soluble CD1a confirmed the prolonged capacity to stimulate T cells. Moreover, other glycosphingolipids bind to all CD1, which suggests the presence of additional promiscuous ligands. Thus, group I CD1 molecules present an overlapping set of self-glycolipids, even though they are quite divergent from an evolutionary point of view.


Assuntos
Apresentação de Antígeno/imunologia , Antígenos CD1/imunologia , Glicoproteínas/imunologia , Sulfoglicoesfingolipídeos/imunologia , Linfócitos T/imunologia , Antígenos CD1/genética , Linhagem Celular , Glicoproteínas/genética , Humanos , Imunofenotipagem , Linfócitos T/citologia
20.
J Exp Med ; 199(7): 947-57, 2004 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-15051763

RESUMO

Class I and class II MHC-restricted T cells specific for proteins present in myelin have been shown to be involved in autoimmunity in the central nervous system (CNS). It is not yet known whether CD1d-restricted T cells reactive to myelin-derived lipids are present in the CNS and might be targeted to influence the course of autoimmune demyelination. Using specific glycolipid-CD1d tetramers and cloned T cells we have characterized a T cell population reactive to a myelin-derived glycolipid, sulfatide, presented by CD1d. This population is distinct from the invariant Valpha14+ NK T cells, and a panel of Valpha3/Valpha8+ CD1d-restricted NK T cell hybridomas is unable to recognize sulfatide in the presence of CD1d+ antigen-presenting cells. Interestingly, during experimental autoimmune encephalomyelitis a model for human multiple sclerosis, sulfatide-reactive T cells but not invariant NK T cells are increased severalfold in CNS tissue. Moreover, treatment of mice with sulfatide prevents antigen-induced experimental autoimmune encephalomyelitis in wild-type but not in CD1d-deficient mice. Disease prevention correlates with the ability of sulfatide to suppress both interferon-gamma and interleukin-4 production by pathogenic myelin oligodendrocyte glycoprotein-reactive T cells. Since recognition of sulfatide by CD1d-restricted T cells has now been shown both in mice and humans, study of murine myelin lipid-reactive T cells may form a basis for the development of intervention strategies in human autoimmune demyelinating diseases.


Assuntos
Antígenos CD1/metabolismo , Autoimunidade , Sulfoglicoesfingolipídeos/imunologia , Subpopulações de Linfócitos T/imunologia , Animais , Apresentação de Antígeno , Antígenos CD1/genética , Antígenos CD1d , Doenças Autoimunes/imunologia , Doenças Autoimunes/prevenção & controle , Doenças Autoimunes Desmielinizantes do Sistema Nervoso Central/imunologia , Doenças Autoimunes Desmielinizantes do Sistema Nervoso Central/prevenção & controle , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/prevenção & controle , Humanos , Interferon gama/biossíntese , Interleucina-4/biossíntese , Células Matadoras Naturais/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas da Mielina , Glicoproteína Associada a Mielina/imunologia , Glicoproteína Mielina-Oligodendrócito
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