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1.
Artigo em Inglês | MEDLINE | ID: mdl-31710506

RESUMO

RATIONALE: Interleukin (IL) 18 is a member of the IL-1 cytokine family and elevated blood IL-18 concentrations associate with disease activity in Macrophage Activation Syndrome (MAS) and poor clinical outcomes in severe inflammatory and septic conditions. OBJECTIVE: While recent investigations provide mechanistic evidence for a contribution of IL-18 to (hyper)inflammation in sepsis and MAS, we sought to study regulatory mechanisms underlying human IL-18 expression. METHODS: Samples from in vivo and in vitro endotoxin re-challenge experiments, inflammatory disease patients and isolated human monocytes treated with various stimulants and drugs were tested for cytokine gene and protein expression. Serum IL-18 expression with or without JAK/STAT-inhibition was analyzed in two MAS mouse models as well as a patient with recurrent MAS. MEASUREMENTS AND MAIN RESULTS: Peripheral blood as well as monocytic IL-18 expression escaped lipopolysacharide (LPS)-induced immunoparalysis. LPS-stimulated primary human monocytes revealed a specific IL-18 expression kinetics controlled by IFNα/ß-signaling. JAK/STAT-inhibition or IFNß-neutralization during LPS-stimulation blunted cytokine expression. Similarly, microtubule destabilizing drugs abrogated LPS-induced IL18 expression, which could be fully reversed by addition of IFNα/ß. Ex vivo analysis of inflammatory disease patients' whole blood revealed strong correlation of type I interferon score and IL18 expression, while JAK/STAT-inhibition in two MAS mouse models as well as a patient with recurrent MAS strongly reduced IL-18 serum levels. CONCLUSION: Our data indicate that IL-18 (but not IL-1ß) production from human monocytes requires cooperate toll-like receptor and IFNα/ß-signaling. Interference with IFNα/ß-expression or signaling following JAK/STAT-inhibition may control catastrophic hyperinflammation in MAS. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).

2.
Blood ; 134(2): 147-159, 2019 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-31015190

RESUMO

Hemophagocytic lymphohistiocytosis (HLH) is an often-fatal disorder characterized by the overactivation of T cells and macrophages that excessively produce proinflammatory cytokines, including interferon-γ (IFN-γ). Previously, we reported that the JAK inhibitor ruxolitinib dampens T-cell activation and lessens inflammation in a model of HLH in which perforin-deficient (Prf1 -/-) mice are infected with lymphocytic choriomeningitis virus (LCMV). Ruxolitinib inhibits signaling downstream of IFN-γ, as well as several other JAK-dependent cytokines. As a consequence, it remained unclear whether ruxolitinib was exerting its beneficial effects in HLH by inhibiting IFN-γ signaling or by targeting signaling initiated by other proinflammatory cytokines. To address this question, we compared the effects of ruxolitinib with those obtained using an IFN-γ-neutralizing antibody (αIFN-γ) in 2 murine HLH models. In both models, ruxolitinib and αIFN-γ reduced inflammation-associated anemia, indicating that ruxolitinib operates in an IFN-γ-dependent manner to reverse this HLH manifestation. In contrast, the number and activation status of T cells and neutrophils, as well as their infiltration into tissues, were significantly reduced following treatment with ruxolitinib, but they remained unchanged or were increased following treatment with αIFN-γ. Notably, despite discontinuation of ruxolitinib, LCMV-infected Prf1 -/- mice exhibited enhanced survival compared with mice in which αIFN-γ was discontinued. This protective effect could be mimicked by transient treatment with αIFN-γ and a neutrophil-depleting antibody. Thus, ruxolitinib operates through IFN-γ-dependent and -independent mechanisms to dampen HLH by targeting the deleterious effects of T cells and neutrophils, with the latter representing an unappreciated and understudied cell type that contributes to HLH pathogenesis.


Assuntos
Linfo-Histiocitose Hemofagocítica/imunologia , Neutrófilos/efeitos dos fármacos , Pirazóis/farmacologia , Linfócitos T/efeitos dos fármacos , Animais , Modelos Animais de Doenças , Ativação Linfocitária/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL
3.
Cancer Cell ; 33(5): 937-948.e8, 2018 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-29681510

RESUMO

Somatic genetic alterations of IKZF1, which encodes the lymphoid transcription factor IKAROS, are common in high-risk B-progenitor acute lymphoblastic leukemia (ALL) and are associated with poor prognosis. Such alterations result in the acquisition of stem cell-like features, overexpression of adhesion molecules causing aberrant cell-cell and cell-stroma interaction, and decreased sensitivity to tyrosine kinase inhibitors. Here we report coding germline IKZF1 variation in familial childhood ALL and 0.9% of presumed sporadic B-ALL, identifying 28 unique variants in 45 children. The majority of variants adversely affected IKZF1 function and drug responsiveness of leukemic cells. These results identify IKZF1 as a leukemia predisposition gene, and emphasize the importance of germline genetic variation in the development of both familial and sporadic ALL.


Assuntos
Mutação em Linhagem Germinativa , Fator de Transcrição Ikaros/genética , Fator de Transcrição Ikaros/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Animais , Criança , Feminino , Mutação da Fase de Leitura , Predisposição Genética para Doença , Humanos , Masculino , Camundongos , Transplante de Neoplasias , Linhagem , Leucemia-Linfoma Linfoblástico de Células Precursoras B/metabolismo , Análise de Sequência de DNA
4.
Cell Host Microbe ; 20(1): 13-24, 2016 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-27321907

RESUMO

Influenza A virus (IAV) is a lytic virus in primary cultures of many cell types and in vivo. We report that the kinase RIPK3 is essential for IAV-induced lysis of mammalian fibroblasts and lung epithelial cells. Replicating IAV drives assembly of a RIPK3-containing complex that includes the kinase RIPK1, the pseudokinase MLKL, and the adaptor protein FADD, and forms independently of signaling by RNA-sensing innate immune receptors (RLRs, TLRs, PKR), or the cytokines type I interferons and TNF-α. Downstream of RIPK3, IAV activates parallel pathways of MLKL-driven necroptosis and FADD-mediated apoptosis, with the former reliant on RIPK3 kinase activity and neither on RIPK1 activity. Mice deficient in RIPK3 or doubly deficient in MLKL and FADD, but not MLKL alone, are more susceptible to IAV than their wild-type counterparts, revealing an important role for RIPK3-mediated apoptosis in antiviral immunity. Collectively, these results outline RIPK3-activated cytolytic mechanisms essential for controlling respiratory IAV infection.


Assuntos
Apoptose , Proteína de Domínio de Morte Associada a Fas/metabolismo , Vírus da Influenza A/crescimento & desenvolvimento , Vírus da Influenza A/imunologia , Necrose , Proteínas Quinases/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Animais , Linhagem Celular , Modelos Animais de Doenças , Células Epiteliais/fisiologia , Células Epiteliais/virologia , Proteína de Domínio de Morte Associada a Fas/genética , Fibroblastos/fisiologia , Fibroblastos/virologia , Humanos , Camundongos , Camundongos Knockout , Infecções por Orthomyxoviridae/patologia , Proteínas Quinases/genética , Multimerização Proteica , Proteína Serina-Treonina Quinases de Interação com Receptores/genética
5.
Nature ; 532(7599): 389-93, 2016 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-27064903

RESUMO

Asymmetric cell division, the partitioning of cellular components in response to polarizing cues during mitosis, has roles in differentiation and development. It is important for the self-renewal of fertilized zygotes in Caenorhabditis elegans and neuroblasts in Drosophila, and in the development of mammalian nervous and digestive systems. T lymphocytes, upon activation by antigen-presenting cells (APCs), can undergo asymmetric cell division, wherein the daughter cell proximal to the APC is more likely to differentiate into an effector-like T cell and the distal daughter is more likely to differentiate into a memory-like T cell. Upon activation and before cell division, expression of the transcription factor c-Myc drives metabolic reprogramming, necessary for the subsequent proliferative burst. Here we find that during the first division of an activated T cell in mice, c-Myc can sort asymmetrically. Asymmetric distribution of amino acid transporters, amino acid content, and activity of mammalian target of rapamycin complex 1 (mTORC1) is correlated with c-Myc expression, and both amino acids and mTORC1 activity sustain the differences in c-Myc expression in one daughter cell compared to the other. Asymmetric c-Myc levels in daughter T cells affect proliferation, metabolism, and differentiation, and these effects are altered by experimental manipulation of mTORC1 activity or c-Myc expression. Therefore, metabolic signalling pathways cooperate with transcription programs to maintain differential cell fates following asymmetric T-cell division.


Assuntos
Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/metabolismo , Divisão Celular , Polaridade Celular , Ativação Linfocitária , Sistemas de Transporte de Aminoácidos/metabolismo , Aminoácidos/metabolismo , Animais , Diferenciação Celular/genética , Polaridade Celular/genética , Feminino , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos , Complexos Multiproteicos/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Transdução de Sinais/genética , Serina-Treonina Quinases TOR/metabolismo , Transcrição Genética
6.
Immunity ; 44(1): 88-102, 2016 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-26795252

RESUMO

The role of apoptosis inducing factor (AIF) in promoting cell death versus survival remains controversial. We report that the loss of AIF in fibroblasts led to mitochondrial electron transport chain defects and loss of proliferation that could be restored by ectopic expression of the yeast NADH dehydrogenase Ndi1. Aif-deficiency in T cells led to decreased peripheral T cell numbers and defective homeostatic proliferation, but thymic T cell development was unaffected. In contrast, Aif-deficient B cells developed and functioned normally. The difference in the dependency of T cells versus B cells on AIF for function and survival correlated with their metabolic requirements. Ectopic Ndi1 expression rescued homeostatic proliferation of Aif-deficient T cells. Despite its reported roles in cell death, fibroblasts, thymocytes and B cells lacking AIF underwent normal death. These studies suggest that the primary role of AIF relates to complex I function, with differential effects on T and B cells.


Assuntos
Fator de Indução de Apoptose/metabolismo , Linfócitos B/metabolismo , Mitocôndrias/fisiologia , Linfócitos T/metabolismo , Animais , Apoptose , Respiração Celular/fisiologia , Complexo I de Transporte de Elétrons/metabolismo , Fibroblastos/metabolismo , Glicólise/fisiologia , Camundongos , Camundongos Knockout , Camundongos Mutantes
7.
Blood ; 127(13): 1666-75, 2016 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-26825707

RESUMO

Hemophagocytic lymphohistiocytosis (HLH) comprises an emerging spectrum of inherited and noninherited disorders of the immune system characterized by the excessive production of cytokines, including interferon-γ and interleukins 2, 6, and 10 (IL-2, IL-6, and IL-10). The Janus kinases (JAKs) transduce signals initiated following engagement of specific receptors that bind a broad array of cytokines, including those overproduced in HLH. Based on the central role for cytokines in the pathogenesis of HLH, we sought to examine whether the inhibition of JAK function might lessen inflammation in murine models of the disease. Toward this end, we examined the effects of JAK inhibition using a model of primary (inherited) HLH in which perforin-deficient (Prf1(-∕-)) mice are infected with lymphocytic choriomeningitis virus (LCMV) and secondary (noninherited) HLH in which C57BL/6 mice receive repeated injections of CpG DNA. In both models, treatment with the JAK1/2 inhibitor ruxolitinib significantly lessened the clinical and laboratory manifestations of HLH, including weight loss, organomegaly, anemia, thrombocytopenia, hypercytokinemia, and tissue inflammation. Importantly, ruxolitinib treatment also significantly improved the survival of LCMV-infectedPrf1(-∕-)mice. Mechanistic studies revealed that in vivo exposure to ruxolitinib inhibited signal transducer and activation of transcription 1-dependent gene expression, limited CD8(+)T-cell expansion, and greatly reduced proinflammatory cytokine production, without effecting degranulation and cytotoxic function. Collectively, these findings highlight the JAKs as novel, druggable targets for mitigating the cytokine-driven hyperinflammation that occurs in HLH. These observations also support the incorporation of JAK inhibitors such as ruxolitinib into future clinical trials for patients with these life-threatening disorders.


Assuntos
Inflamação/prevenção & controle , Janus Quinases/antagonistas & inibidores , Ativação Linfocitária/efeitos dos fármacos , Linfo-Histiocitose Hemofagocítica/genética , Linfo-Histiocitose Hemofagocítica/patologia , Pirazóis/farmacologia , Animais , Células Cultivadas , Ilhas de CpG , Modelos Animais de Doenças , Linfo-Histiocitose Hemofagocítica/tratamento farmacológico , Linfo-Histiocitose Hemofagocítica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Perforina/genética , Pirazóis/uso terapêutico , Células Vero
8.
Sci Transl Med ; 8(321): 321ra7, 2016 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-26764158

RESUMO

X-linked lymphoproliferative disease (XLP-1) is an often-fatal primary immunodeficiency associated with the exuberant expansion of activated CD8(+) T cells after Epstein-Barr virus (EBV) infection. XLP-1 is caused by defects in signaling lymphocytic activation molecule (SLAM)-associated protein (SAP), an adaptor protein that modulates T cell receptor (TCR)-induced signaling. SAP-deficient T cells exhibit impaired TCR restimulation-induced cell death (RICD) and diminished TCR-induced inhibition of diacylglycerol kinase α (DGKα), leading to increased diacylglycerol metabolism and decreased signaling through Ras and PKCθ (protein kinase Cθ). We show that down-regulation of DGKα activity in SAP-deficient T cells restores diacylglycerol signaling at the immune synapse and rescues RICD via induction of the proapoptotic proteins NUR77 and NOR1. Pharmacological inhibition of DGKα prevents the excessive CD8(+) T cell expansion and interferon-γ production that occur in SAP-deficient mice after lymphocytic choriomeningitis virus infection without impairing lytic activity. Collectively, these data highlight DGKα as a viable therapeutic target to reverse the life-threatening EBV-associated immunopathology that occurs in XLP-1 patients.


Assuntos
Diacilglicerol Quinase/antagonistas & inibidores , Transtornos Linfoproliferativos/imunologia , Transtornos Linfoproliferativos/patologia , Animais , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/metabolismo , Morte Celular/efeitos dos fármacos , Citocinas/biossíntese , Diacilglicerol Quinase/metabolismo , Inativação Gênica/efeitos dos fármacos , Humanos , Sinapses Imunológicas/efeitos dos fármacos , Sinapses Imunológicas/metabolismo , Ativação Linfocitária , Contagem de Linfócitos , Transtornos Linfoproliferativos/tratamento farmacológico , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Proteína Quinase C/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Pirimidinonas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Proteína Associada à Molécula de Sinalização da Ativação Linfocitária/deficiência , Proteína Associada à Molécula de Sinalização da Ativação Linfocitária/metabolismo , Tiazóis/farmacologia , Proteínas ras/metabolismo
9.
Cell ; 157(5): 1189-202, 2014 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-24813850

RESUMO

Receptor-interacting protein kinase (RIPK)-1 is involved in RIPK3-dependent and -independent signaling pathways leading to cell death and/or inflammation. Genetic ablation of ripk1 causes postnatal lethality, which was not prevented by deletion of ripk3, caspase-8, or fadd. However, animals that lack RIPK1, RIPK3, and either caspase-8 or FADD survived weaning and matured normally. RIPK1 functions in vitro to limit caspase-8-dependent, TNFR-induced apoptosis, and animals lacking RIPK1, RIPK3, and TNFR1 survive to adulthood. The role of RIPK3 in promoting lethality in ripk1(-/-) mice suggests that RIPK3 activation is inhibited by RIPK1 postbirth. Whereas TNFR-induced RIPK3-dependent necroptosis requires RIPK1, cells lacking RIPK1 were sensitized to necroptosis triggered by poly I:C or interferons. Disruption of TLR (TRIF) or type I interferon (IFNAR) signaling delayed lethality in ripk1(-/-)tnfr1(-/-) mice. These results clarify the complex roles for RIPK1 in postnatal life and provide insights into the regulation of FADD-caspase-8 and RIPK3-MLKL signaling by RIPK1.


Assuntos
Caspase 8/metabolismo , Genes Letais , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Animais , Animais Recém-Nascidos , Apoptose , Caspase 8/genética , Morte Celular , Embrião de Mamíferos/citologia , Embrião de Mamíferos/metabolismo , Proteína de Domínio de Morte Associada a Fas/metabolismo , Fibroblastos/metabolismo , Inflamação/metabolismo , Interferons/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteína Serina-Treonina Quinases de Interação com Receptores/genética , Receptores Tipo I de Fatores de Necrose Tumoral/genética , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Fatores de Necrose Tumoral/metabolismo
10.
Cell Metab ; 17(6): 895-900, 2013 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-23747248

RESUMO

The innate immune response is shaped by multiple factors, including both traditional autophagy and LC3-associated phagocytosis (LAP). As the autophagic machinery is engaged during times of nutrient stress, arising from scarcity or pathogens, we examine how autophagy, specifically LAP, and cellular metabolism together influence macrophage function and the innate immune response.


Assuntos
Autofagia/imunologia , Metabolismo Energético , Proteínas Associadas aos Microtúbulos/metabolismo , Fagocitose/imunologia , Humanos , Imunidade Inata , Macrófagos/imunologia , Macrófagos/metabolismo , Proteínas Associadas aos Microtúbulos/imunologia , Fagossomos/imunologia , Fagossomos/metabolismo , Transdução de Sinais/imunologia
11.
Cytokine ; 59(3): 467-78, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22704694

RESUMO

An effective immune response to an invading viral pathogen requires the combined actions of both innate and adaptive immune cells. For example, NK cells and cytotoxic CD8 T cells are capable of the direct engagement of infected cells and the mediation of antiviral responses. Both NK and CD8 T cells depend on common gamma chain (γc) cytokine signals for their development and homeostasis. The γc cytokine IL-15 is very well characterized for its role in promoting the development and homeostasis of NK cells and CD8 T cells, but emerging literature suggests that IL-15 mediates the anti-viral responses of these cell populations during an active immune response. Both NK cells and CD8 T cells must become activated, migrate to sites of infection, survive at those sites, and expand in order to maximally exert effector functions, and IL-15 can modulate each of these processes. This review focuses on the functions of IL-15 in the regulation of multiple aspects of NK and CD8 T cell biology, investigates the mechanisms by which IL-15 may exert such diverse functions, and discusses how these different facets of IL-15 biology may be therapeutically exploited to combat viral diseases.


Assuntos
Imunidade/imunologia , Interleucina-15/imunologia , Vírus/imunologia , Animais , Humanos , Linfócitos/imunologia , Viroses/imunologia , Viroses/terapia
12.
PLoS One ; 7(5): e37539, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22624047

RESUMO

Following influenza infection, natural killer (NK) cells function as interim effectors by suppressing viral replication until CD8 T cells are activated, proliferate, and are mobilized within the respiratory tract. Thus, NK cells are an important first line of defense against influenza virus. Here, in a murine model of influenza, we show that virally-induced IL-15 facilitates the trafficking of NK cells into the lung airways. Blocking IL-15 delays NK cell entry to the site of infection and results in a disregulated control of early viral replication. By the same principle, viral control by NK cells can be therapeutically enhanced via intranasal administration of exogenous IL-15 in the early days post influenza infection. In addition to controlling early viral replication, this IL-15-induced mobilization of NK cells to the lung airways has important downstream consequences on adaptive responses. Primarily, depletion of responding NK1.1+ NK cells is associated with reduced immigration of influenza-specific CD8 T cells to the site of infection. Together this work suggests that local deposits of IL-15 in the lung airways regulate the coordinated innate and adaptive immune responses to influenza infection and may represent an important point of immune intervention.


Assuntos
Imunidade Inata/imunologia , Interleucina-15/imunologia , Células Matadoras Naturais/imunologia , Infecções por Orthomyxoviridae/imunologia , Sistema Respiratório/imunologia , Animais , Lavagem Broncoalveolar , Movimento Celular/efeitos dos fármacos , Movimento Celular/imunologia , Citometria de Fluxo , Interleucina-15/farmacologia , Células Matadoras Naturais/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Sistema Respiratório/virologia
13.
Semin Immunol ; 24(6): 399-404, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23313070

RESUMO

As T cells respond to pathogens, they must transition from a quiescent, naïve state, to a rapidly proliferating, active effector state, and back again to a quiescent state as they develop into memory cells. Such transitions place unique metabolic demands on the differentiating cells. T cells meet these demands by altering their metabolic profiles, which are, in turn, regulated by distinct signaling cascades and transcriptional programs. Here, we examine the metabolic profiles of T cells during an acute immune response and discuss the signal and transcriptional regulators of these metabolic changes.


Assuntos
Regulação da Expressão Gênica , Ativação Linfocitária/imunologia , Linfócitos T , Diferenciação Celular , Humanos , Memória Imunológica , Linfócitos T/citologia , Linfócitos T/imunologia , Linfócitos T/metabolismo
14.
J Immunol ; 186(12): 6667-71, 2011 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-21572025

RESUMO

Effective vaccines against intracellular pathogens rely on the generation and maintenance of memory CD8 T cells (T(mem)). Hitherto, evidence has indicated that CD8 T(mem) use the common γ-chain cytokine IL-15 for their steady-state maintenance in the absence of Ag. This evidence, however, has been amassed predominantly from models of acute, systemic infections. Given that the route of infection can have significant impact on the quantity and quality of the resultant T(mem), reliance on limited models of infection may restrict our understanding of long-term CD8 T(mem) survival. In this article, we show IL-15-independent generation, maintenance, and function of CD8 T(mem) after respiratory infection with influenza virus. Importantly, we demonstrate that alternating between mucosal and systemic deliveries of the identical virus prompts this change in IL-15 dependence, necessitating a re-evaluation of the current model of CD8 T(mem) maintenance.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Memória Imunológica/imunologia , Interleucina-15/imunologia , Membrana Mucosa/imunologia , Humanos , Influenza Humana/imunologia , Orthomyxoviridae/imunologia
15.
J Immunol ; 186(1): 174-82, 2011 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-21098221

RESUMO

The cytokines generated locally in response to infection play an important role in CD8 T cell trafficking, survival, and effector function, rendering these signals prime candidates for immune intervention. In this paper, we show that localized increases in the homeostatic cytokine IL-15 induced by influenza infection is responsible for the migration of CD8 effector T cells to the site of infection. Moreover, intranasal delivery of IL-15-IL-15Rα soluble complexes (IL-15c) specifically restores the frequency of effector T cells lost in the lung airways of IL-15-deficient animals after influenza infection. Exogenous IL-15c quantitatively augments the respiratory CD8 T cell response, and continued administration of IL-15c throughout the contraction phase of the anti-influenza CD8 T cell response magnifies the resultant CD8 T cell memory generated in situ. This treatment extends the ability of these cells to protect against heterologous infection, immunity that typically depreciates over time. Overall, our studies describe what to our knowledge is a new function for IL-15 in attracting effector CD8 T cells to the lung airways and suggest that adjuvanting IL-15 could be used to prolong anti-influenza CD8 T cell responses at mucosal surfaces to facilitate pathogen elimination.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Movimento Celular/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Interleucina-15/fisiologia , Pulmão/imunologia , Pulmão/virologia , Infecções por Orthomyxoviridae/imunologia , Animais , Linfócitos T CD8-Positivos/patologia , Linfócitos T CD8-Positivos/virologia , Diferenciação Celular/imunologia , Memória Imunológica , Interleucina-15/biossíntese , Pulmão/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Infecções por Orthomyxoviridae/metabolismo , Infecções por Orthomyxoviridae/prevenção & controle , Pneumonia Viral/imunologia , Pneumonia Viral/metabolismo , Pneumonia Viral/prevenção & controle , Infecções Respiratórias/imunologia , Infecções Respiratórias/prevenção & controle , Infecções Respiratórias/virologia
16.
Biochem J ; 429(3): 485-95, 2010 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-20497125

RESUMO

Acidocalcisomes are acidic calcium-storage compartments described from bacteria to humans and characterized by their high content in poly P (polyphosphate), a linear polymer of many tens to hundreds of Pi residues linked by high-energy phosphoanhydride bonds. In the present paper we report that millimolar levels of short-chain poly P (in terms of Pi residues) and inorganic PPi are present in sea urchin extracts as detected using 31P-NMR, enzymatic determinations and agarose gel electrophoresis. Poly P was localized to granules randomly distributed in the sea urchin eggs, as shown by labelling with the poly-P-binding domain of Escherichia coli exopolyphosphatase. These granules were enriched using iodixanol centrifugation and shown to be acidic and to contain poly P, as determined by Acridine Orange and DAPI (4',6'-diamidino-2-phenylindole) staining respectively. These granules also contained large amounts of calcium, sodium, magnesium, potassium and zinc, as detected by X-ray microanalysis, and bafilomycin A1-sensitive ATPase, pyrophosphatase and exopolyphosphatase activities, as well as Ca2+/H+ and Na+/H+ exchange activities, being therefore similar to acidocalcisomes described in other organisms. Calcium release from these granules induced by nigericin was associated with poly P hydrolysis. Although NAADP (nicotinic acid-adenine dinucleotide phosphate) released calcium from the granule fraction, this activity was not significantly enriched as compared with the NAADP-stimulated calcium release from homogenates and was not accompanied by poly P hydrolysis. GPN (glycyl-L-phenylalanine-naphthylamide) released calcium when added to sea urchin homogenates, but was unable to release calcium from acidocalcisome-enriched fractions, suggesting that these acidic stores are not the targets for NAADP.


Assuntos
Cálcio/metabolismo , Grânulos Citoplasmáticos/metabolismo , NADP/análogos & derivados , Óvulo/metabolismo , Polifosfatos/metabolismo , Ácidos/metabolismo , Animais , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , NADP/metabolismo , Óvulo/ultraestrutura , Ouriços-do-Mar
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