Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 91
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Annu Rev Immunol ; 32: 323-66, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24499274

RESUMO

Over the past 15 years, investigators have shown that T lymphocytes can recognize not only peptides in the context of MHC class I and class II molecules but also foreign and self-lipids in association with the nonclassical MHC class I-like molecules, CD1 proteins. In this review, we describe the most recent events in the field, with particular emphasis on (a) structural and functional aspects of lipid presentation by CD1 molecules, (b) the development of CD1d-restricted invariant natural killer T (iNKT) cells and transcription factors required for their differentiation, (c) the ability of iNKT cells to modulate innate and adaptive immune responses through their cross talk with lymphoid and myeloid cells, and (d) MR1-restricted and group I (CD1a, CD1b, and CD1c)-restricted T cells.


Assuntos
Antígenos CD1/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Células T Matadoras Naturais/imunologia , Animais , Antígenos CD1/metabolismo , Diferenciação Celular , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Ligantes , Ativação Linfocitária/imunologia , Antígenos de Histocompatibilidade Menor , Mucosa/citologia , Mucosa/imunologia , Mucosa/metabolismo , Células T Matadoras Naturais/citologia , Células T Matadoras Naturais/metabolismo , Nódulos Linfáticos Agregados/citologia , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/metabolismo , Ligação Proteica/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Especificidade do Receptor de Antígeno de Linfócitos T/imunologia
2.
Nat Immunol ; 21(11): 1336-1345, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32887977

RESUMO

The development of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines and therapeutics will depend on understanding viral immunity. We studied T cell memory in 42 patients following recovery from COVID-19 (28 with mild disease and 14 with severe disease) and 16 unexposed donors, using interferon-γ-based assays with peptides spanning SARS-CoV-2 except ORF1. The breadth and magnitude of T cell responses were significantly higher in severe as compared with mild cases. Total and spike-specific T cell responses correlated with spike-specific antibody responses. We identified 41 peptides containing CD4+ and/or CD8+ epitopes, including six immunodominant regions. Six optimized CD8+ epitopes were defined, with peptide-MHC pentamer-positive cells displaying the central and effector memory phenotype. In mild cases, higher proportions of SARS-CoV-2-specific CD8+ T cells were observed. The identification of T cell responses associated with milder disease will support an understanding of protective immunity and highlights the potential of including non-spike proteins within future COVID-19 vaccine design.


Assuntos
Antígenos Virais/imunologia , Betacoronavirus/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Memória Imunológica/imunologia , COVID-19 , Vacinas contra COVID-19 , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/patologia , Infecções por Coronavirus/prevenção & controle , Epitopos de Linfócito T/imunologia , Humanos , Epitopos Imunodominantes/imunologia , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/patologia , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/imunologia , Reino Unido , Vacinas Virais/imunologia
3.
Nat Immunol ; 20(4): 514, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30862955

RESUMO

In the version of this article initially published, the first affiliation lacked 'MRC'; the correct name of the institution is 'MRC Weatherall Institute of Molecular Medicine'. Two designations (SP110Y and ST110H) were incorrect in the legend to Fig. 6f,h,i. The correct text is as follows: for panel f, "...loaded with either the CdtB(105-125)SP110Y (DRB4*SP110Y) or the CdtB(105-125)ST110H (DRB4*ST110H) peptide variants..."; for panel h, "...decorated by the DRB4*SP110Y tetramer (lower-right quadrant), the DRB4*ST110H (upper-left quadrant)..."; and for panel i, "...stained ex vivo with DRB4*SP110Y, DRB4*ST110H...". In Fig. 8e, the final six residues (LTEAFF) of the sequence in the far right column of the third row of the table were missing; the correct sequence is 'CASSYRRTPPLTEAFF'. In the legend to Fig. 8d, a designation (HLyE) was incorrect; the correct text is as follows: "(HlyE?)." Portions of the Acknowledgements section were incorrect; the correct text is as follows: "This work was supported by the UK Medical Research Council (MRC) (MR/K021222/1) (G.N., M.A.G., A.S., V.C., A.J.P.),...the Oxford Biomedical Research Centre (A.J.P., V.C.),...and core funding from the Singapore Immunology Network (SIgN) (E.W.N.) and the SIgN immunomonitoring platform (E.W.N.)." Finally, a parenthetical element was phrased incorrectly in the final paragraph of the Methods subsection "T cell cloning and live fluorescence barcoding"; the correct phrasing is as follows: "...(which in all cases included HlyE, CdtB, Ty21a, Quailes, NVGH308, and LT2 strains and in volunteers T5 and T6 included PhoN)...". Also, in Figs. 3c and 4a, the right outlines of the plots were not visible; in the legend to Fig. 3, panel letter 'f' was not bold; and in Fig. 8f, 'ND' should be aligned directly beneath DRB4 in the key and 'ND' should be removed from the diagram at right, and the legend should be revised accordingly as follows: "...colors indicate the HLA class II restriction (gray indicates clones for which restriction was not determined (ND)). Clonotypes are grouped on the basis of pathogen selectivity (continuous line), protein specificity (dashed line) and epitope specificity; for ten HlyE-specific clones (pixilated squares), the epitope specificity was not determined...". The errors have been corrected in the HTML and PDF versions of the article.

4.
Nat Immunol ; 19(7): 742-754, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29925993

RESUMO

To tackle the complexity of cross-reactive and pathogen-specific T cell responses against related Salmonella serovars, we used mass cytometry, unbiased single-cell cloning, live fluorescence barcoding, and T cell-receptor sequencing to reconstruct the Salmonella-specific repertoire of circulating effector CD4+ T cells, isolated from volunteers challenged with Salmonella enterica serovar Typhi (S. Typhi) or Salmonella Paratyphi A (S. Paratyphi). We describe the expansion of cross-reactive responses against distantly related Salmonella serovars and of clonotypes recognizing immunodominant antigens uniquely expressed by S. Typhi or S. Paratyphi A. In addition, single-amino acid variations in two immunodominant proteins, CdtB and PhoN, lead to the accumulation of T cells that do not cross-react against the different serovars, thus demonstrating how minor sequence variations in a complex microorganism shape the pathogen-specific T cell repertoire. Our results identify immune-dominant, serovar-specific, and cross-reactive T cell antigens, which should aid in the design of T cell-vaccination strategies against Salmonella.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Salmonella paratyphi A/imunologia , Salmonella typhi/imunologia , ADP-Ribosil Ciclase 1/análise , Adulto , Antígenos de Bactérias/imunologia , Antígenos de Bactérias/metabolismo , Linfócitos T CD4-Positivos/química , Células Clonais , Humanos , Fenótipo , Receptores CCR7/análise , Febre Tifoide/imunologia
5.
Proc Natl Acad Sci U S A ; 121(19): e2318003121, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38691588

RESUMO

Peptides presented by HLA-E, a molecule with very limited polymorphism, represent attractive targets for T cell receptor (TCR)-based immunotherapies to circumvent the limitations imposed by the high polymorphism of classical HLA genes in the human population. Here, we describe a TCR-based bispecific molecule that potently and selectively binds HLA-E in complex with a peptide encoded by the inhA gene of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis in humans. We reveal the biophysical and structural bases underpinning the potency and specificity of this molecule and demonstrate its ability to redirect polyclonal T cells to target HLA-E-expressing cells transduced with mycobacterial inhA as well as primary cells infected with virulent Mtb. Additionally, we demonstrate elimination of Mtb-infected cells and reduction of intracellular Mtb growth. Our study suggests an approach to enhance host T cell immunity against Mtb and provides proof of principle for an innovative TCR-based therapeutic strategy overcoming HLA polymorphism and therefore applicable to a broader patient population.


Assuntos
Antígenos de Histocompatibilidade Classe I , Mycobacterium tuberculosis , Receptores de Antígenos de Linfócitos T , Linfócitos T , Mycobacterium tuberculosis/imunologia , Humanos , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Linfócitos T/imunologia , Antígenos HLA-E , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Tuberculose/imunologia
6.
Semin Immunol ; 61-64: 101663, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36306661

RESUMO

Mucosal Associated Invariant T cells (MAIT) exert potent antimicrobial activity through direct recognition of metabolite-MR1 complexes and indirect activation by inflammatory cytokines. Additionally, via licensing of antigen presenting cells, MAIT cells orchestrate humoral and cellular adaptive immunity. Our recent understanding of molecular mechanisms of MAIT cell activation, and of the signals required to differentiate them in polarised subsets, pave the way for harnessing their functionality through small molecules or adoptive cell therapy.


Assuntos
Infecções Bacterianas , Células T Invariantes Associadas à Mucosa , Humanos , Infecções Bacterianas/terapia , Citocinas , Antígenos de Histocompatibilidade Classe I , Ativação Linfocitária
7.
J Biol Chem ; 298(2): 101542, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34968463

RESUMO

The monomorphic antigen-presenting molecule major histocompatibility complex-I-related protein 1 (MR1) presents small-molecule metabolites to mucosal-associated invariant T (MAIT) cells. The MR1-MAIT cell axis has been implicated in a variety of infectious and noncommunicable diseases, and recent studies have begun to develop an understanding of the molecular mechanisms underlying this specialized antigen presentation pathway. However, proteins regulating MR1 folding, loading, stability, and surface expression remain to be identified. Here, we performed a gene trap screen to discover novel modulators of MR1 surface expression through insertional mutagenesis of an MR1-overexpressing clone derived from the near-haploid human cell line HAP1 (HAP1.MR1). The most significant positive regulators identified included ß2-microglobulin, a known regulator of MR1 surface expression, and ATP13A1, a P5-type ATPase in the endoplasmic reticulum (ER) not previously known to be associated with MR1-mediated antigen presentation. CRISPR/Cas9-mediated knockout of ATP13A1 in both HAP1.MR1 and THP-1 cell lines revealed a profound reduction in MR1 protein levels and a concomitant functional defect specific to MR1-mediated antigen presentation. Collectively, these data are consistent with the ER-resident ATP13A1 being a key posttranscriptional determinant of MR1 surface expression.


Assuntos
Apresentação de Antígeno , Antígenos de Histocompatibilidade Classe I , Complexo Principal de Histocompatibilidade , Antígenos de Histocompatibilidade Menor , ATPases do Tipo-P , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Complexo Principal de Histocompatibilidade/imunologia , Antígenos de Histocompatibilidade Menor/imunologia , ATPases do Tipo-P/imunologia
8.
Proc Natl Acad Sci U S A ; 117(19): 10465-10475, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32341160

RESUMO

The antigen-presenting molecule MR1 presents riboflavin-based metabolites to Mucosal-Associated Invariant T (MAIT) cells. While MR1 egress to the cell surface is ligand-dependent, the ability of small-molecule ligands to impact on MR1 cellular trafficking remains unknown. Arising from an in silico screen of the MR1 ligand-binding pocket, we identify one ligand, 3-([2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-yl]formamido)propanoic acid, DB28, as well as an analog, methyl 3-([2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-yl]formamido)propanoate, NV18.1, that down-regulate MR1 from the cell surface and retain MR1 molecules in the endoplasmic reticulum (ER) in an immature form. DB28 and NV18.1 compete with the known MR1 ligands, 5-OP-RU and acetyl-6-FP, for MR1 binding and inhibit MR1-dependent MAIT cell activation. Crystal structures of the MAIT T cell receptor (TCR) complexed with MR1-DB28 and MR1-NV18.1, show that these two ligands reside within the A'-pocket of MR1. Neither ligand forms a Schiff base with MR1 molecules; both are nevertheless sequestered by a network of hydrophobic and polar contacts. Accordingly, we define a class of compounds that inhibits MR1 cellular trafficking.


Assuntos
Antígenos de Histocompatibilidade Classe I/metabolismo , Antígenos de Histocompatibilidade Menor/metabolismo , Células T Invariantes Associadas à Mucosa/metabolismo , Apresentação de Antígeno , Linhagem Celular , Membrana Celular/metabolismo , Regulação para Baixo , Regulação da Expressão Gênica/genética , Humanos , Ligantes , Ativação Linfocitária , Transporte Proteico , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Riboflavina/metabolismo , Células THP-1
9.
Proc Natl Acad Sci U S A ; 117(34): 20717-20728, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32788367

RESUMO

Mucosal-associated invariant T (MAIT) cells are innate T lymphocytes activated by bacteria that produce vitamin B2 metabolites. Mouse models of infection have demonstrated a role for MAIT cells in antimicrobial defense. However, proposed protective roles of MAIT cells in human infections remain unproven and clinical conditions associated with selective absence of MAIT cells have not been identified. We report that typhoidal and nontyphoidal Salmonella enterica strains activate MAIT cells. However, S. Typhimurium sequence type 313 (ST313) lineage 2 strains, which are responsible for the burden of multidrug-resistant nontyphoidal invasive disease in Africa, escape MAIT cell recognition through overexpression of ribB This bacterial gene encodes the 4-dihydroxy-2-butanone-4-phosphate synthase enzyme of the riboflavin biosynthetic pathway. The MAIT cell-specific phenotype did not extend to other innate lymphocytes. We propose that ribB overexpression is an evolved trait that facilitates evasion from immune recognition by MAIT cells and contributes to the invasive pathogenesis of S. Typhimurium ST313 lineage 2.


Assuntos
Células T Invariantes Associadas à Mucosa/imunologia , Salmonella typhimurium/genética , Salmonella typhimurium/metabolismo , África Subsaariana , Antibacterianos , Diarreia/microbiologia , Diarreia/mortalidade , Humanos , Evasão da Resposta Imune/genética , Evasão da Resposta Imune/fisiologia , Células T Invariantes Associadas à Mucosa/metabolismo , Infecções por Salmonella/imunologia , Salmonella typhimurium/patogenicidade
10.
Nat Immunol ; 11(11): 1039-46, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20890286

RESUMO

Neutrophils are the main effector cells during inflammation, but they can also control excessive inflammatory responses by secreting anti-inflammatory cytokines. However, the mechanisms that modulate their plasticity remain unclear. We now show that systemic serum amyloid A 1 (SAA-1) controls the plasticity of neutrophil differentiation. SAA-1 not only induced anti-inflammatory interleukin 10 (IL-10)-secreting neutrophils but also promoted the interaction of invariant natural killer T cells (iNKT cells) with those neutrophils, a process that limited their suppressive activity by diminishing the production of IL-10 and enhancing the production of IL-12. Because SAA-1-producing melanomas promoted differentiation of IL-10-secreting neutrophils, harnessing iNKT cells could be useful therapeutically by decreasing the frequency of immunosuppressive neutrophils and restoring tumor-specific immune responses.


Assuntos
Diferenciação Celular/imunologia , Interleucina-10/imunologia , Melanoma/imunologia , Células T Matadoras Naturais/imunologia , Neutrófilos/imunologia , Proteína Amiloide A Sérica/imunologia , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Neutrófilos/citologia
11.
Proc Natl Acad Sci U S A ; 116(47): 23671-23681, 2019 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-31690657

RESUMO

Invariant NKT (iNKT) cells have the unique ability to shape immunity during antitumor immune responses and other forms of sterile and nonsterile inflammation. Recent studies have highlighted a variety of classes of endogenous and pathogen-derived lipid antigens that can trigger iNKT cell activation under sterile and nonsterile conditions. However, the context and mechanisms that drive the presentation of self-lipid antigens in sterile inflammation remain unclear. Here we report that endoplasmic reticulum (ER)-stressed myeloid cells, via signaling events modulated by the protein kinase RNA-like ER kinase (PERK) pathway, increase CD1d-mediated presentation of immunogenic endogenous lipid species, which results in enhanced iNKT cell activation both in vitro and in vivo. In addition, we demonstrate that actin cytoskeletal reorganization during ER stress results in an altered distribution of CD1d on the cell surface, which contributes to enhanced iNKT cell activation. These results define a previously unidentified mechanism that controls iNKT cell activation during sterile inflammation.


Assuntos
Células Apresentadoras de Antígenos/imunologia , Células Dendríticas/imunologia , Estresse do Retículo Endoplasmático/imunologia , Ativação Linfocitária , Células T Matadoras Naturais/imunologia , Animais , Apresentação de Antígeno , Antígenos CD1d/biossíntese , Antígenos CD1d/imunologia , Autoantígenos/imunologia , Carcinoma Pulmonar de Lewis/patologia , Linhagem Celular Tumoral , Técnicas de Cocultura , Citoesqueleto/ultraestrutura , Endossomos/imunologia , Glicoesfingolipídeos/imunologia , Glicoesfingolipídeos/metabolismo , Humanos , Subunidade alfa de Receptor de Interleucina-2/biossíntese , Lipídeos/imunologia , Lisossomos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Células THP-1 , Tapsigargina/farmacologia , Resposta a Proteínas não Dobradas/imunologia , eIF-2 Quinase/deficiência , eIF-2 Quinase/fisiologia
12.
Br J Cancer ; 124(4): 817-830, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33214684

RESUMO

BACKGROUND: Interferon (IFN) signalling pathways, a key element of the innate immune response, contribute to resistance to conventional chemotherapy, radiotherapy, and immunotherapy, and are often deregulated in cancer. The deubiquitylating enzyme USP18 is a major negative regulator of the IFN signalling cascade and is the predominant human protease that cleaves ISG15, a ubiquitin-like protein tightly regulated in the context of innate immunity, from its modified substrate proteins in vivo. METHODS: In this study, using advanced proteomic techniques, we have significantly expanded the USP18-dependent ISGylome and proteome in a chronic myeloid leukaemia (CML)-derived cell line. USP18-dependent effects were explored further in CML and colorectal carcinoma cellular models. RESULTS: Novel ISGylation targets were characterised that modulate the sensing of innate ligands, antigen presentation and secretion of cytokines. Consequently, CML USP18-deficient cells are more antigenic, driving increased activation of cytotoxic T lymphocytes (CTLs) and are more susceptible to irradiation. CONCLUSIONS: Our results provide strong evidence for USP18 in regulating antigenicity and radiosensitivity, highlighting its potential as a cancer target.


Assuntos
Neoplasias Colorretais/enzimologia , Neoplasias Colorretais/imunologia , Citocinas/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/enzimologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/imunologia , Ubiquitina Tiolesterase/metabolismo , Ubiquitinas/metabolismo , Variação Antigênica , Linhagem Celular Tumoral , Neoplasias Colorretais/radioterapia , Técnicas de Inativação de Genes , Células HCT116 , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/radioterapia , Tolerância a Radiação/genética , Tolerância a Radiação/imunologia , Ubiquitina Tiolesterase/deficiência , Ubiquitina Tiolesterase/genética
13.
J Immunol ; 199(8): 2631-2638, 2017 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-28877992

RESUMO

Mucosal-associated invariant T (MAIT) cells are innate T cells that recognize intermediates of the vitamin B2 biosynthetic pathway presented by the monomorphic MR1 molecule. It remains unclear whether, in addition to their cytolytic activity that is important in antimicrobial defense, MAIT cells have immune-modulatory functions that could enhance dendritic cell (DC) maturation. In this study, we investigated the molecular mechanisms dictating the interactions between human MAIT cells and DCs and demonstrate that human MAIT cells mature monocyte-derived and primary DCs in an MR1- and CD40L-dependent manner. Furthermore, we show that MAIT cell-derived signals synergize with microbial stimuli to induce secretion of bioactive IL-12 by DCs. Activation of human MAIT cells in whole blood leads to MR1- and cytokine-dependent NK cell transactivation. Our results underscore an important property of MAIT cells, which can be of translational relevance to rapidly orchestrate adaptive immunity through DC maturation.


Assuntos
Células Dendríticas/imunologia , Ativação Linfocitária , Células T Matadoras Naturais/imunologia , Ligante de CD40/metabolismo , Comunicação Celular , Diferenciação Celular , Células Cultivadas , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Imunidade nas Mucosas , Interleucina-12/metabolismo , Antígenos de Histocompatibilidade Menor/metabolismo , Monócitos/imunologia , Receptor Cross-Talk , Riboflavina/imunologia , Riboflavina/metabolismo , Transdução de Sinais
14.
Proc Natl Acad Sci U S A ; 113(6): E772-81, 2016 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-26798067

RESUMO

Invariant natural killer T (iNKT) cells recognize endogenous and exogenous lipid antigens presented in the context of CD1d molecules. The ability of iNKT cells to recognize endogenous antigens represents a distinct immune recognition strategy, which underscores the constitutive memory phenotype of iNKT cells and their activation during inflammatory conditions. However, the mechanisms regulating such "tonic" activation of iNKT cells remain unclear. Here, we show that the spatiotemporal distribution of CD1d molecules on the surface of antigen-presenting cells (APCs) modulates activation of iNKT cells. By using superresolution microscopy, we show that CD1d molecules form nanoclusters at the cell surface of APCs, and their size and density are constrained by the actin cytoskeleton. Dual-color single-particle tracking revealed that diffusing CD1d nanoclusters are actively arrested by the actin cytoskeleton, preventing their further coalescence. Formation of larger nanoclusters occurs in the absence of interactions between CD1d cytosolic tail and the actin cytoskeleton and correlates with enhanced iNKT cell activation. Importantly and consistently with iNKT cell activation during inflammatory conditions, exposure of APCs to the Toll-like receptor 7/8 agonist R848 increases nanocluster density and iNKT cell activation. Overall, these results define a previously unidentified mechanism that modulates iNKT cell autoreactivity based on the tight control by the APC cytoskeleton of the sizes and densities of endogenous antigen-loaded CD1d nanoclusters.


Assuntos
Citoesqueleto de Actina/metabolismo , Células Apresentadoras de Antígenos/metabolismo , Antígenos CD1d/metabolismo , Nanopartículas/química , Células T Matadoras Naturais/metabolismo , Linhagem Celular , Membrana Celular/metabolismo , Difusão , Galactosilceramidas/metabolismo , Humanos , Inflamação/patologia , Ativação Linfocitária , Modelos Biológicos , Monócitos/metabolismo , Transporte Proteico , Análise Espaço-Temporal
15.
Eur J Immunol ; 46(1): 242-52, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26518614

RESUMO

The role of CD1a-reactive T cells in human allergic disease is unknown. We have previously shown that circulating CD1a-reactive T cells recognize neolipid antigens generated by bee and wasp venom phospholipase, and here tested the hypothesis that venom-responsive CD1a-reactive T cells associate with venom allergy. Circulating T cells from bee and wasp venom allergic individuals, before and during immunotherapy, were exposed to CD1a-transfected K562 cells in the presence of wasp or bee venom. T-cell response was evaluated based on IFNγ, GM-CSF, and IL-13 cytokine production. Venom allergic individuals showed significantly higher frequencies of IFN-γ, GM-CSF, and IL-13 producing CD1a-reactive T cells responsive to venom and venom-derived phospholipase than healthy individuals. Venom-responsive CD1a-reactive T cells were cross-responsive between wasp and bee suggesting shared pathways of allergenicity. Frequencies of CD1a-reactive T cells were initially induced during subcutaneous immunotherapy, peaking by weeks 5, but then reduced despite escalation of antigen dose. Our current understanding of venom allergy and immunotherapy is largely based on peptide and protein-specific T cell and antibody responses. Here, we show that lipid antigens and CD1a-reactive T cells associate with the allergic response. These data have implications for mechanisms of allergy and approaches to immunotherapy.


Assuntos
Venenos de Abelha/imunologia , Hipersensibilidade/imunologia , Linfócitos T/imunologia , Venenos de Vespas/imunologia , Adulto , Alérgenos/imunologia , Animais , Antígenos CD1/imunologia , Venenos de Abelha/efeitos adversos , Separação Celular , Reações Cruzadas , Dessensibilização Imunológica , Ensaio de Imunoadsorção Enzimática , ELISPOT , Feminino , Humanos , Mordeduras e Picadas de Insetos/imunologia , Masculino , Pessoa de Meia-Idade , Venenos de Vespas/efeitos adversos
16.
Blood ; 125(8): 1200-2, 2015 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-25700422

RESUMO

In this issue of Blood, Nair et al describe a new population of type II natural killer T (NKT) cells with follicular helper phenotype (TFH), which is more abundant in patients and mice with Gaucher disease (GD) and is capable of regulating B-cell activity.


Assuntos
Linfócitos B/imunologia , Inflamação/imunologia , Lipídeos/imunologia , Células T Matadoras Naturais/fisiologia , Linfócitos T Auxiliares-Indutores/fisiologia , Animais , Humanos
17.
Proc Natl Acad Sci U S A ; 111(52): E5678-87, 2014 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-25512546

RESUMO

Autophagy is an evolutionarily conserved cellular homeostatic pathway essential for development, immunity, and cell death. Although autophagy modulates MHC antigen presentation, it remains unclear whether autophagy defects impact on CD1d lipid loading and presentation to invariant natural killer T (iNKT) cells and on iNKT cell differentiation in the thymus. Furthermore, it remains unclear whether iNKT and conventional T cells have similar autophagy requirements for differentiation, survival, and/or activation. We report that, in mice with a conditional deletion of the essential autophagy gene Atg7 in the T-cell compartment (CD4 Cre-Atg7(-/-)), thymic iNKT cell development--unlike conventional T-cell development--is blocked at an early stage and mature iNKT cells are absent in peripheral lymphoid organs. The defect is not due to altered loading of intracellular iNKT cell agonists; rather, it is T-cell-intrinsic, resulting in enhanced susceptibility of iNKT cells to apoptosis. We show that autophagy increases during iNKT cell thymic differentiation and that it developmentally regulates mitochondrial content through mitophagy in the thymus of mice and humans. Autophagy defects result in the intracellular accumulation of mitochondrial superoxide species and subsequent apoptotic cell death. Although autophagy-deficient conventional T cells develop normally, they show impaired peripheral survival, particularly memory CD8(+) T cells. Because iNKT cells, unlike conventional T cells, differentiate into memory cells while in the thymus, our results highlight a unique autophagy-dependent metabolic regulation of adaptive and innate T cells, which is required for transition to a quiescent state after population expansion.


Assuntos
Autofagia/imunologia , Linfócitos T CD8-Positivos/imunologia , Diferenciação Celular/imunologia , Memória Imunológica , Células T Matadoras Naturais/imunologia , Timo/imunologia , Animais , Apoptose/genética , Apoptose/imunologia , Autofagia/genética , Proteína 7 Relacionada à Autofagia , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/citologia , Diferenciação Celular/genética , Sobrevivência Celular/genética , Sobrevivência Celular/imunologia , Camundongos , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/imunologia , Células T Matadoras Naturais/citologia , Superóxidos/imunologia , Timo/citologia
18.
Eur J Immunol ; 45(1): 309-16, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25263407

RESUMO

Viral diversity is a challenge to the development of a hepatitis C virus (HCV) vaccine. Following vaccination of humans with adenoviral vectors, we determined the capacity of T cells to target common viral variants at immundominant epitopes ex vivo. We identified two major variants for epitopes NS3(1073) and NS3(1446), and multiple variants for epitope NS3(1406) that occurred in >5% of genotype 1 and 3 sequences at a population level. Cross-reactivity of vaccine-induced T cells was determined using variant peptides in IFN-γ ELISPOT assays. Vaccine-induced T cells targeted approximately 90% of NS3(1073) genotype 1 sequences and 50% of NS3(1446) genotype 1 and 3 sequences. For NS3(1406), 62% of subtype-1b sequences were targeted. Next, we assessed whether an in vitro priming system, using dendritic cells and T cells from healthy donors, could identify a variant of NS3(1406) that was maximally cross-reactive. In vitro priming assays showed that of those tested the NS3(1406) vaccine variant was the most immunogenic. T cells primed with genotype 1 variants from subtype 1a or 1b were broadly cross-reactive with other variants from the same subtype. We conclude that immunization with candidate HCV adenoviral vaccines generates cross-reactive T cells at immunodominant epitopes. The degree of cross-reactivity varies between epitopes and may be HCV-subtype specific.


Assuntos
Antígenos Virais/imunologia , Epitopos de Linfócito T/imunologia , Hepacivirus/imunologia , Hepatite C/prevenção & controle , Linfócitos T/imunologia , Proteínas não Estruturais Virais/imunologia , Sequência de Aminoácidos , Antígenos Virais/genética , Linhagem Celular , Reações Cruzadas , Células Dendríticas/citologia , Células Dendríticas/imunologia , ELISPOT , Epitopos de Linfócito T/genética , Genótipo , Hepacivirus/genética , Hepatite C/imunologia , Hepatite C/virologia , Humanos , Interferon gama/genética , Interferon gama/imunologia , Interferon gama/metabolismo , Dados de Sequência Molecular , Cultura Primária de Células , Linfócitos T/citologia , Vacinação , Vacinas contra Hepatite Viral/administração & dosagem , Proteínas não Estruturais Virais/genética
19.
Proc Natl Acad Sci U S A ; 110(49): E4753-61, 2013 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-24248359

RESUMO

Lipid transfer proteins, such as molecules of the saposin family, facilitate extraction of lipids from biological membranes for their loading onto CD1d molecules. Although it has been shown that prosaposin-deficient mice fail to positively select invariant natural killer T (iNKT) cells, it remains unclear whether saposins can facilitate loading of endogenous iNKT cell agonists in the periphery during inflammatory responses. In addition, it is unclear whether saposins, in addition to loading, also promote dissociation of lipids bound to CD1d molecules. To address these questions, we used a combination of cellular assays and demonstrated that saposins influence CD1d-restricted presentation to human iNKT cells not only of exogenous lipids but also of endogenous ligands, such as the self-glycosphingolipid ß-glucopyranosylceramide, up-regulated by antigen-presenting cells following bacterial infection. Furthermore, we demonstrated that in human myeloid cells CD1d-loading of endogenous lipids after bacterial infection, but not at steady state, requires trafficking of CD1d molecules through an endo-lysosomal compartment. Finally, using BIAcore assays we demonstrated that lipid-loaded saposin B increases the off-rate of lipids bound to CD1d molecules, providing important insights into the mechanisms by which it acts as a "lipid editor," capable of fine-tuning loading and unloading of CD1d molecules. These results have important implications in understanding how to optimize lipid-loading onto antigen-presenting cells, to better harness iNKT cells central role at the interface between innate and adaptive immunity.


Assuntos
Antígenos CD1d/metabolismo , Imunidade Inata/imunologia , Metabolismo dos Lipídeos/fisiologia , Células T Matadoras Naturais/imunologia , Saposinas/metabolismo , Células Apresentadoras de Antígenos/imunologia , Bactérias/imunologia , Ensaio de Imunoadsorção Enzimática , Células HEK293 , Humanos , Imunoprecipitação , Contagem de Cintilação
20.
J Immunol ; 189(6): 3007-17, 2012 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-22875802

RESUMO

Recognition of endogenous lipid Ag(s) on CD1d is required for the development of invariant NKT (iNKT) cells. Isoglobotrihexosylceramide (iGb3) has been implicated as this endogenous selecting ligand and recently suggested to control overstimulation and deletion of iNKT cells in α-galactosidase A-deficient (αGalA(-/-)) mice (human Fabry disease), which accumulate isoglobosides and globosides. However, the presence and function of iGb3 in murine thymus remained controversial. In this study, we generate a globotrihexosylceramide (Gb3)-synthase-deficient (Gb3S(-/-)) mouse and show that in thymi of αGalA(-/-)/Gb3S(-/-) double-knockout mice, which store isoglobosides but no globosides, minute amounts of iGb3 can be detected by HPLC. Furthermore, we demonstrate that iGb3 deficiency does not only fail to impact selection of iNKT cells, in terms of frequency and absolute numbers, but also does not alter the distribution of the TCR CDR 3 of iNKT cells. Analyzing multiple gene-targeted mouse strains, we demonstrate that globoside, rather than iGb3, storage is the major cause for reduced iNKT cell frequencies and defective Ag presentation in αGalA(-/-) mice. Finally, we show that correction of globoside storage in αGalA(-/-) mice by crossing them with Gb3S(-/-) normalizes iNKT cell frequencies and dendritic cell (DC) function. We conclude that, although detectable in murine thymus in αGalA(-/-)/Gb3S(-/-) mice, iGb3 does not influence either the development of iNKT cells or their interaction with peripheral DCs. Moreover, in αGalA(-/-) mice, it is the Gb3 storage that is responsible for the decreased iNKT cell numbers and impeded Ag presentation on DCs.


Assuntos
Diferenciação Celular/imunologia , Células Dendríticas/imunologia , Globosídeos/fisiologia , Células T Matadoras Naturais/imunologia , Triexosilceramidas , Animais , Sequência de Carboidratos , Células Dendríticas/enzimologia , Células Dendríticas/metabolismo , Globosídeos/deficiência , Fígado/citologia , Fígado/enzimologia , Fígado/metabolismo , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Dados de Sequência Molecular , Células T Matadoras Naturais/enzimologia , Células T Matadoras Naturais/metabolismo , Baço/citologia , Baço/enzimologia , Baço/metabolismo , Timo/citologia , Timo/enzimologia , Timo/metabolismo , Triexosilceramidas/deficiência , Triexosilceramidas/fisiologia , alfa-Galactosidase/genética , alfa-Galactosidase/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA