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1.
Pathog Immun ; 3(1): 2-18, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29541698

RESUMO

Background: Hepatitis B virus (HBV) affects up to 400 million people worldwide and accounts for approximately one million deaths per year from liver pathologies. Current treatment regimens are effective in suppressing viremia but usually have to be taken indefinitely, warranting research into new therapeutic approaches. Acute HBV infection in adults almost universally results in resolution of viremia, with the exception of immunocompromised persons, suggesting that the immune response can functionally cure or even eradicate HBV infection. Methods: Because immunophenotypic and functional studies have implicated a role for Natural Killer (NK) cells in HBV clearance during acute infection, we hypothesized that a distinct NK-cell profile exists in acute HBV infection that could provide information for the mechanism of HBV clearance. Using multivariate flow cytometry, we evaluated the expression of key activating and inhibitory receptors on NK cells, and their ability to respond to classic target cell lines. Results: Multivariate analysis revealed selective perturbation of the CD56dim NK-cell subset during acute infection, displaying low levels of NKp46+, NKp30+, CD160+ and CD161+ cells. Intriguingly, the CD56dim NK-cell profile predicted time to HBV surface antigen (HBsAg) clearance from the blood, and distinct NK-cell profiles predicted early (NKp30, CD94, CD161) and late clearance (KIR3DL1, CD158a, perforin, NKp46). Finally, functional analysis demonstrated that early and late clearance tracked with elevated degranulation (CD107a) or IFNγ production, respectively, in response to ADCC-mediated activation. Conclusion: The cytolytic CD56dim NK-cell subset is selectively activated in acute HBV infection and displays distinct phenotypic and functional profiles associated with efficient and early control of HBV, implicating antibody-mediated cytolytic NK-cell responses in the early control and functional cure of HBV infection.

2.
PLoS One ; 9(8): e105950, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25148254

RESUMO

Although epidemiological and functional studies have implicated NK cells in protection and early clearance of HCV, the mechanism by which they may contribute to viral control is poorly understood, particularly at the site of infection, the liver. We hypothesized that a unique immunophenotypic/functional NK cell signature exists in the liver that may provide insights into the contribution of NK cells to viral control. Intrahepatic and blood NK cells were profiled from chronically infected HCV-positive and HCV-negative individuals. Baseline expression of activating and inhibitory receptors was assessed, as well as functional responses following stimulation through classic NK cell pathways. Independent of HCV infection, the liver was enriched for the immunoregulatory CD56(bright) NK cell population, which produced less IFNγ and CD107a but comparable levels of MIP1ß, and was immunophenotypically distinct from their blood counterparts. This profile was mostly unaltered in chronic HCV infection, though different expression levels of NKp46 and NKG2D were associated with different grades of fibrosis. In contrast to the liver, chronic HCV infection associated with an enrichment of CD161(low)perforin(high) NK cells in the blood correlated with increased AST and 2B4 expression. However, the association of relatively discrete changes in the NK cell phenotype in the liver with the fibrosis stage nevertheless suggests an important role for the NK response. Overall these data suggest that tissue localization has a more pervasive effect on NK cells than the presence of chronic viral infection, during which these cells might be mostly attuned to limiting immunopathology. It will be important to characterize NK cells during early HCV infection, when they should have a critical role in limiting infection.


Assuntos
Antígeno CD56/metabolismo , Hepatite C Crônica/patologia , Células Matadoras Naturais/imunologia , Fígado/patologia , Idoso , Feminino , Hepatite C Crônica/imunologia , Humanos , Imunofenotipagem , Células Matadoras Naturais/metabolismo , Células Matadoras Naturais/patologia , Fígado/virologia , Cirrose Hepática/imunologia , Cirrose Hepática/patologia , Masculino , Pessoa de Meia-Idade , Subfamília B de Receptores Semelhantes a Lectina de Células NK/metabolismo , Subfamília K de Receptores Semelhantes a Lectina de Células NK/metabolismo , Receptor 1 Desencadeador da Citotoxicidade Natural/metabolismo , Perforina/metabolismo , Fenótipo
3.
Integr Biol (Camb) ; 4(10): 1175-84, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22945136

RESUMO

Natural killer (NK) cells are a subset of innate immune lymphocytes that interrogate potential target cells and rapidly respond by lysing them or secreting inflammatory immunomodulators. Productive interactions between NK cells and targets such as tumor cells or virally infected cells are critical for immunological control of malignancies and infections. For individual NK cells, however, the relationship between the characteristics of these cell-cell interactions, cytolysis, and secretory activity is not well understood. Here, we used arrays of subnanoliter wells (nanowells) to monitor individual NK cell-target cell interactions and quantify the resulting cytolytic and secretory responses. We show that NK cells operate independently when lysing a single target cell and that lysis is most probable during an NK cell's first encounter with a target. Furthermore, we demonstrate that the secretion of interferon-γ (IFN-γ) occurs most often among NK cells that become the least motile upon contacting a target cell but is largely independent of cytolysis. Our findings demonstrate that integrated analysis of the cell-cell interaction parameters, cytolytic activity, and secretory activity of single NK cells can reveal new insights into how these complex functions are related within individual cells.


Assuntos
Células Matadoras Naturais/citologia , Citometria de Fluxo/métodos , Humanos , Fatores Imunológicos/química , Inflamação , Interferon gama/metabolismo , Interleucina-2/metabolismo , Células K562 , Células Matadoras Naturais/imunologia , Leucócitos Mononucleares/citologia , Contagem de Linfócitos , Linfócitos/citologia , Microscopia de Vídeo/métodos , Nanopartículas/química , Nanotecnologia/métodos , Ligação Proteica , Fatores de Tempo
4.
J Immunol ; 188(7): 3315-22, 2012 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-22345646

RESUMO

NK cells play an important role in innate immunity. A previous genome-wide association study demonstrated an association between a 17q12 allele (rs9916629(C)) and lower frequency of CD3(-)CD56(+) NK cells in peripheral blood. We performed an analysis that not only replicates the original result of the genome-wide association study (p = 0.036) but also defines the specific cell subpopulations and functions that are modulated by the rs9916629 polymorphism in a cohort of 96 healthy adult subjects using targeted multiparameter flow cytometric profiling of NK cell phenotypes and functions. We found that rs9916629(C) is associated with alterations in specific NK cell subsets, including lower frequency of predominantly cytotoxic CD56(dim) NK cells (p = 0.011), higher frequency of predominantly regulatory CD56(bright) NK cells (p = 0.019), and a higher proportion of NK cells expressing the inhibitory NKG2A receptor (p = 0.0002). Functionally, rs9916629(C) is associated with decreased secretion of macrophage inflammatory protein-1ß by NK cells in the context of Ab-dependent cell-mediated cytotoxicity (p = 0.039) and increased degranulation in response to MHC class I-deficient B cells (p = 0.017). Transcriptional profiling of NK cells suggests that rs9916629 influences the expression of transcription factors such as TBX21, which has a role in NK cell differentiation, offering a possible mechanism for the phenotypic and functional differences between the different alleles. The rs9916629(C) allele therefore has a validated effect on the proportion of NK cells in peripheral blood and skews NK cells toward a specific phenotypic and functional profile, potentially influencing the impact that these innate immune cells have on infection and autoimmunity.


Assuntos
Alelos , Cromossomos Humanos Par 17/genética , Células Matadoras Naturais/imunologia , Polimorfismo de Nucleotídeo Único , Adulto , Citotoxicidade Celular Dependente de Anticorpos , Antígeno CD56/análise , Separação Celular , Quimiocina CCL4/metabolismo , Mapeamento Cromossômico , Citotoxicidade Imunológica , Feminino , Citometria de Fluxo , Humanos , Imunofenotipagem , Células Matadoras Naturais/classificação , Células Matadoras Naturais/metabolismo , Contagem de Linfócitos , Linfopoese , Masculino , Subfamília C de Receptores Semelhantes a Lectina de Células NK/análise , Transcrição Genética/imunologia
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