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










Intervalo de ano de publicação
1.
Int J Mol Sci ; 22(7)2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33807467

RESUMO

The major components of the cytokinin (CK) signaling pathway have been identified from the receptors to their downstream transcription factors. However, since signaling proteins are encoded by multigene families, characterizing and quantifying the contribution of each component or their combinations to the signaling cascade have been challenging. Here, we describe a transient gene expression system in rice (Oryza sativa) protoplasts suitable to reconstitute CK signaling branches using the CK reporter construct TCSn:fLUC, consisting of a synthetic CK-responsive promoter and the firefly luciferase gene, as a sensitive readout of signaling output. We used this system to systematically test the contributions of CK signaling components, either alone or in various combinations, with or without CK treatment. The type-B response regulators (RRs) OsRR16, OsRR17, OsRR18, and OsRR19 all activated TCSn:fLUC strongly, with OsRR18 and OsRR19 showing the strongest induction by CK. Cotransfecting the reporter with OsHP01, OsHP02, OsHP05, or OsHK03 alone resulted in much weaker effects relative to those of the type-B OsRRs. When we tested combinations of OsHK03, OsHPs, and OsRRs, each combination exhibited distinct CK signaling activities. This system thus allows the rapid and high-throughput exploration of CK signaling in rice.


Assuntos
Citocininas/metabolismo , Oryza/genética , Protoplastos/metabolismo , Citocininas/imunologia , Regulação da Expressão Gênica de Plantas/genética , Genes de Plantas/genética , Oryza/imunologia , Oryza/metabolismo , Reguladores de Crescimento de Plantas/genética , Proteínas de Plantas/genética , Brotos de Planta/genética , Regiões Promotoras Genéticas/genética , Protoplastos/imunologia , Transdução de Sinais/imunologia
2.
J Neuroinflammation ; 15(1): 301, 2018 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-30376851

RESUMO

BACKGROUND: Neonatal brain injury is increasingly understood to be linked to inflammatory processes that involve specialised CNS and peripheral immune interactions. However, the role of peripheral myeloid cells in neonatal hypoxic-ischemic (HI) brain injury remains to be fully investigated. METHODS: We employed the Lys-EGFP-ki mouse that allows enhanced green fluorescent protein (EGFP)-positive mature myeloid cells of peripheral origin to be easily identified in the CNS. Using both flow cytometry and confocal microscopy, we investigated the accumulation of total EGFP+ myeloid cells and myeloid cell subtypes: inflammatory monocytes, resident monocytes and granulocytes, in the CNS for several weeks following induction of cerebral HI in postnatal day 9 mice. We used antibody treatment to curb brain infiltration of myeloid cells and subsequently evaluated HI-induced brain injury. RESULTS: We demonstrate a temporally biphasic pattern of inflammatory monocyte and granulocyte infiltration, characterised by peak infiltration at 1 day and 7 days after hypoxia-ischemia. This occurs against a backdrop of continuous low-level resident monocyte infiltration. Antibody-mediated depletion of circulating myeloid cells reduced immune cell accumulation in the brain and reduced neuronal loss in male but not female mice. CONCLUSION: This study offers new insight into sex-dependent central-peripheral immune communication following neonatal brain injury and merits renewed interest in the roles of granulocytes and monocytes in lesion development.


Assuntos
Hipóxia-Isquemia Encefálica/imunologia , Hipóxia-Isquemia Encefálica/patologia , Células Mieloides/fisiologia , Animais , Animais Recém-Nascidos , Anticorpos/farmacologia , Antígenos Ly/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Citocininas/genética , Citocininas/imunologia , Citocininas/metabolismo , Modelos Animais de Doenças , Lateralidade Funcional/fisiologia , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas dos Microfilamentos/metabolismo , Monócitos/efeitos dos fármacos , Monócitos/patologia , Muramidase/genética , Muramidase/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neutrófilos/efeitos dos fármacos , Neutrófilos/patologia
3.
Toxicol Lett ; 219(1): 42-8, 2013 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-23454833

RESUMO

The immunological adjuvant effect of silver nanoparticles (AgNPs) was investigated both in vitro and in vivo. The in vivo adjuvant effect of AgNPs was evaluated with model antigen ovalbumin (OVA) and bovine serum albumin (BSA) in mice by intraperitoneal and subcutaneous immunization. Serum antigen-specific IgG level significantly increased in AgNPs-treated mice comparing to the control group. AgNPs induced the increase of IgG1/IgG2a ratio and antigen-specific IgE, indicating that AgNPs elicited Th2-biased immune responses. By in vitro assay, the mechanism of adjuvant effect was explored. After 48h treatment with AgNPs, both the number of leukocytes and levels of cytokines TNF-α and IFN-γ in abdominal lavage fluid of mice increased. The expression of the major histocompatibility complex class II molecule on the surface of peritoneal macrophages significantly increased. AgNPs can be easily phagocytosed by peritoneal macrophages, while do not affect antigen uptake by the cell. We therefore conclude that AgNPs have significant adjuvant effect and the mechanism of this effect is mainly ascribed to the recruitment and activation of local leukocytes and especially macrophages. For the first time we found the remarkable adjuvant effect of AgNPs, and the result is beneficial for the future applications, especially in biomedicine.


Assuntos
Adjuvantes Imunológicos/farmacologia , Hipersensibilidade/imunologia , Nanopartículas Metálicas , Prata/farmacologia , Adjuvantes Imunológicos/química , Animais , Formação de Anticorpos/efeitos dos fármacos , Formação de Anticorpos/imunologia , Citocininas/análise , Citocininas/imunologia , Feminino , Antígenos de Histocompatibilidade Classe II/biossíntese , Antígenos de Histocompatibilidade Classe II/imunologia , Imunização , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Isotipos de Imunoglobulinas/sangue , Isotipos de Imunoglobulinas/imunologia , Leucócitos/efeitos dos fármacos , Leucócitos/imunologia , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Ovalbumina/imunologia , Tamanho da Partícula , Soroalbumina Bovina/imunologia , Prata/química , Prata/imunologia , Propriedades de Superfície
5.
Annu Rev Plant Biol ; 63: 353-80, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22554243

RESUMO

Despite long-standing observations on diverse cytokinin actions, the discovery path to cytokinin signaling mechanisms was tortuous. Unyielding to conventional genetic screens, experimental innovations were paramount in unraveling the core cytokinin signaling circuitry, which employs a large repertoire of genes with overlapping and specific functions. The canonical two-component transcription circuitry involves His kinases that perceive cytokinin and initiate signaling, as well as His-to-Asp phosphorelay proteins that transfer phosphoryl groups to response regulators, transcriptional activators, or repressors. Recent advances have revealed the complex physiological functions of cytokinins, including interactions with auxin and other signal transduction pathways. This review begins by outlining the historical path to cytokinin discovery and then elucidates the diverse cytokinin functions and key signaling components. Highlights focus on the integration of cytokinin signaling components into regulatory networks in specific contexts, ranging from molecular, cellular, and developmental regulations in the embryo, root apical meristem, shoot apical meristem, stem and root vasculature, and nodule organogenesis to organismal responses underlying immunity, stress tolerance, and senescence.


Assuntos
Proteínas de Transporte/metabolismo , Citocininas/metabolismo , Ácidos Indolacéticos/metabolismo , Redes e Vias Metabólicas/fisiologia , Desenvolvimento Vegetal/fisiologia , Transdução de Sinais/fisiologia , Arabidopsis/genética , Arabidopsis/metabolismo , Diferenciação Celular/fisiologia , Citocininas/imunologia , Humanos , Meristema/crescimento & desenvolvimento , Meristema/metabolismo , Floema/citologia , Fosfotransferases/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Nódulos Radiculares de Plantas/metabolismo , Sementes/metabolismo , Estresse Fisiológico/fisiologia , Xilema/citologia
6.
PLoS Genet ; 8(1): e1002448, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22291601

RESUMO

Recent studies have revealed an important role for hormones in plant immunity. We are now beginning to understand the contribution of crosstalk among different hormone signaling networks to the outcome of plant-pathogen interactions. Cytokinins are plant hormones that regulate development and responses to the environment. Cytokinin signaling involves a phosphorelay circuitry similar to two-component systems used by bacteria and fungi to perceive and react to various environmental stimuli. In this study, we asked whether cytokinin and components of cytokinin signaling contribute to plant immunity. We demonstrate that cytokinin levels in Arabidopsis are important in determining the amplitude of immune responses, ultimately influencing the outcome of plant-pathogen interactions. We show that high concentrations of cytokinin lead to increased defense responses to a virulent oomycete pathogen, through a process that is dependent on salicylic acid (SA) accumulation and activation of defense gene expression. Surprisingly, treatment with lower concentrations of cytokinin results in increased susceptibility. These functions for cytokinin in plant immunity require a host phosphorelay system and are mediated in part by type-A response regulators, which act as negative regulators of basal and pathogen-induced SA-dependent gene expression. Our results support a model in which cytokinin up-regulates plant immunity via an elevation of SA-dependent defense responses and in which SA in turn feedback-inhibits cytokinin signaling. The crosstalk between cytokinin and SA signaling networks may help plants fine-tune defense responses against pathogens.


Assuntos
Arabidopsis/imunologia , Citocininas/imunologia , Citocininas/metabolismo , Regulação da Expressão Gênica de Plantas/imunologia , Imunidade Vegetal/imunologia , Ácido Salicílico/imunologia , Ácido Salicílico/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Histidina Quinase , Interações Hospedeiro-Patógeno/imunologia , Mutação , Oomicetos/imunologia , Oomicetos/patogenicidade , Plantas Geneticamente Modificadas , Proteínas Quinases/metabolismo , Receptores de Superfície Celular/metabolismo , Transdução de Sinais
7.
Plant Physiol ; 157(2): 815-30, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21813654

RESUMO

Cytokinins are phytohormones that are involved in various regulatory processes throughout plant development, but they are also produced by pathogens and known to modulate plant immunity. A novel transgenic approach enabling autoregulated cytokinin synthesis in response to pathogen infection showed that cytokinins mediate enhanced resistance against the virulent hemibiotrophic pathogen Pseudomonas syringae pv tabaci. This was confirmed by two additional independent transgenic approaches to increase endogenous cytokinin production and by exogenous supply of adenine- and phenylurea-derived cytokinins. The cytokinin-mediated resistance strongly correlated with an increased level of bactericidal activities and up-regulated synthesis of the two major antimicrobial phytoalexins in tobacco (Nicotiana tabacum), scopoletin and capsidiol. The key role of these phytoalexins in the underlying mechanism was functionally proven by the finding that scopoletin and capsidiol substitute in planta for the cytokinin signal: phytoalexin pretreatment increased resistance against P. syringae. In contrast to a cytokinin defense mechanism in Arabidopsis (Arabidopsis thaliana) based on salicylic acid-dependent transcriptional control, the cytokinin-mediated resistance in tobacco is essentially independent from salicylic acid and differs in pathogen specificity. It is also independent of jasmonate levels, reactive oxygen species, and high sugar resistance. The novel function of cytokinins in the primary defense response of solanaceous plant species is rather mediated through a high phytoalexin-pathogen ratio in the early phase of infection, which efficiently restricts pathogen growth. The implications of this mechanism for the coevolution of host plants and cytokinin-producing pathogens and the practical application in agriculture are discussed.


Assuntos
Citocininas/metabolismo , Nicotiana/microbiologia , Nicotiana/fisiologia , Pseudomonas syringae/patogenicidade , Ácido Salicílico/metabolismo , Sesquiterpenos/metabolismo , Anti-Infecciosos/metabolismo , Ciclopentanos/metabolismo , Citocininas/genética , Citocininas/imunologia , Resistência à Doença , Interações Hospedeiro-Patógeno , Oxilipinas/metabolismo , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Imunidade Vegetal , Folhas de Planta/microbiologia , Plantas Geneticamente Modificadas , Escopoletina/metabolismo , Nicotiana/genética , beta-Frutofuranosidase/metabolismo , Fitoalexinas
8.
Trends Plant Sci ; 16(7): 388-94, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21470894

RESUMO

Cytokinins are plant growth promoting hormones involved in the specification of embryonic cells, maintenance of meristematic cells, shoot formation and development of vasculature. Cytokinins have also emerged as a major factor in plant-microbe interactions during nodule organogenesis and pathogenesis. Microbe-originated cytokinins confer abnormal hypersensitivity of cytokinins to plants, augmenting the sink activity of infected regions. However, recent findings have shed light on a distinct role of cytokinins in plant immune responses. Plant-borne cytokinins systemically induce resistance against pathogen infection. This resistance is orchestrated by endogenous cytokinin and salicylic acid signaling. Here, we discuss how plant- and pathogen-derived cytokinins inversely affect the plant defense response. In addition, we consider the molecular mechanisms underlying plant-derived cytokinin action in plant immunity.


Assuntos
Citocininas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Imunidade Vegetal , Plantas/imunologia , Plantas/metabolismo , Citocininas/imunologia , Reguladores de Crescimento de Plantas/imunologia , Fenômenos Fisiológicos Vegetais , Plantas/microbiologia , Ácido Salicílico/metabolismo , Transdução de Sinais
9.
Phytochemistry ; 69(11): 2214-24, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18561963

RESUMO

We have developed a simple, high-throughput batch immunoextraction (IAE) micropurification procedure for extracting a wide range of naturally occurring cytokinins (bases, ribosides, O- and N-glucosides, and nucleotides) from plant tissues in solutions that are compatible with ultra-performance liquid chromatography (UPLC), thereby facilitating sensitive subsequent analysis. The UPLC system was coupled to a tandem quadrupole mass spectrometer (MS/MS) equipped with an electrospray interface (ESI). Small (mg) amounts of tissues were purified by solid-phase extraction (SPE) followed by an immunoaffinity clean-up step and two fast chromatographic separations of most cytokinin metabolites (bases, ribosides, and 9-glucosides in the first, O-glucosides and nucleotides in the second). Using UPLC, the runs were up to 4-fold faster than in standard cytokinin analyses, and both retention times and injection volumes were less variable (RSDs, 0.15-0.3% and 1.0-5.5%, respectively). In multiple reaction monitoring (MRM) mode, the detection limit for most of the cytokinins analyzed was close to 1 fmol (5-25 fmol for O-glucosides and nucleotides) and the linear range spanned at least five orders of magnitude. The extraction and purification method was optimized using poplar (Populusxcanadensis Moench, cv Robusta) leaf samples, and the analytical accuracy was further validated using IAE-purified 10-day-old Arabidopsis thaliana plants spiked with 1 and 10 pmol of cytokinin derivatives. This approach can be used for rapid, sensitive qualitative and/or quantitative analysis of more than 50 natural cytokinins in minute amounts of plant tissues with high performance, robustness, and accuracy.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Citocininas/química , Plantas/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrometria de Massas em Tandem/métodos , Citocininas/imunologia , Citocininas/isolamento & purificação , Estrutura Molecular , Extratos Vegetais/química , Extratos Vegetais/imunologia , Fatores de Tempo
10.
Adv Immunol ; 88: 97-160, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16227089

RESUMO

Mast cells and basophils are the only cells expressing the tetrameric (alphabetagamma2) structure of the high affinity receptor for IgE (FcepsilonRI) and synthesizing histamine in humans. Human FcepsilonRI+ cells are conventionally considered primary effector cells of bronchial asthma. There is now compelling evidence that these cells differ immunologically, biochemically, and pharmacologically, which suggests that they might play distinct roles in the appearance and fluctuation of the asthma phenotype. Recent data have revealed the complexity of the involvement of human mast cells and basophils in asthma and have shed light on the control of recruitment and activation of these cells in different lung compartments. Preliminary evidence suggests that these cells might not always be detrimental in asthma but, under some circumstances, they might exert a protective effect by modulating certain aspects of innate and acquired immunity and allergic inflammation.


Assuntos
Asma/imunologia , Basófilos/metabolismo , Histamina/metabolismo , Mastócitos/metabolismo , Receptores de IgG/metabolismo , Adenilil Ciclases/imunologia , Adenilil Ciclases/metabolismo , Antígenos de Diferenciação/imunologia , Antígenos de Diferenciação/metabolismo , Asma/patologia , Asma/fisiopatologia , Asma/terapia , Basófilos/imunologia , Basófilos/ultraestrutura , Movimento Celular/imunologia , Proliferação de Células , Citocininas/imunologia , Citocininas/metabolismo , Eicosanoides/imunologia , Eicosanoides/metabolismo , Histamina/imunologia , Humanos , Imunoglobulina E/imunologia , Imunoglobulina E/metabolismo , Mastócitos/imunologia , Mastócitos/ultraestrutura , Prostaglandina D2/imunologia , Prostaglandina D2/metabolismo , Receptores de IgG/genética , Receptores de IgG/imunologia , Transdução de Sinais/imunologia , Ativação Transcricional/imunologia , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/imunologia , Fator A de Crescimento do Endotélio Vascular/metabolismo
12.
Pol J Pharmacol ; 55(3): 353-62, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14506314

RESUMO

Major depression is accompanied by an activation of the inflammatory response system (IRS) and antidepressants may have immunoregulatory activities. This study was carried out to compare the effect of imipramine, mianserin and lithium on the in vitro production of Th1-like cytokines, such as IL-2, IFN-gamma, lymphotoxin and Th2-like cytokines such as IL-4, IL-10 as well as IL-12 and TGF-beta. Peripheral blood mononuclear cells (PBMC) of 16 healthy volunteers were stimulated with polyclonal activators (phytohemagglutinin with lipopolysaccharide PHA + LPS) with or without incubation with imipramine, mianserin (1 microM) or lithium (1 mM). Imipramine and mianserin exhibited similar activities enhancing unstimulated IFN-gamma and IL-10 production. In PHA + LPS-stimulated PBMC both antidepressants inhibited IFN-gamma, IL-2 and lymphotoxin production (Th1-like cytokines) as well as IL-12 and IL-4 production. Under the same in vitro conditions, both antidepressants stimulated production of negative immunoregulatory cytokines such as IL-10 and TGF-beta. Lithium differed significantly from imipramine and mianserin, as it enhanced IL-2, IFN-gamma, IL-10 and TGF-beta production and inhibited only IL-4. All three examined antidepressants reduced IFN-gamma/IL-10 ratio. None of the antidepressants at the used concentrations induced apoptosis in PBMC so those changes in cytokine production were not the result of selective killing of certain cell subpopulations. Imipramine and mianserin at high concentrations negatively influenced reactive oxygen species (ROS) production in neutrophils, however, at concentrations in the therapeutical range none of the antidepressants used influenced "oxidative burst" in neutrophils. The results indicate that antidepressants exert immunoregulatory effects on human leukocyte functions, especially on cytokine production.


Assuntos
Adjuvantes Imunológicos/farmacologia , Antidepressivos/farmacologia , Apoptose/imunologia , Citocininas/imunologia , Leucócitos Mononucleares/efeitos dos fármacos , Neutrófilos/efeitos dos fármacos , Adulto , Apoptose/efeitos dos fármacos , Citocininas/biossíntese , Feminino , Humanos , Imipramina/farmacologia , Técnicas In Vitro , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Lipopolissacarídeos/farmacologia , Lítio/farmacologia , Masculino , Mianserina/farmacologia , Neutrófilos/imunologia , Neutrófilos/metabolismo , Fito-Hemaglutininas/farmacologia , Espécies Reativas de Oxigênio/imunologia , Espécies Reativas de Oxigênio/metabolismo
13.
Mycopathologia ; 148(2): 87-95, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11189749

RESUMO

Infection of Hordeum vulgare L. by Pyrenophora teres and of Zea mays by Dreschslera maydis were characterized by 'green island' formation, higher cytokinin levels and accumulation of metabolites in the infected areas. Higher cytokinin concentrations of the order 6-Y,Y-dimethylallylaminopurine > zeatinriboside > zeatin > dihydrozeatinriboside were detected at infection sites of susceptible hosts. By virtue of these cytokinins, infection sites may be acting as metabolic sinks helping proliferation of the pathogen. Existence of translocatory sinks at infection zones was confirmed from autoradiographic studies, where, accumulation of labeled metabolites was prominent at infection sites of susceptible hosts. Upon infection the lower cytokinin levels of resistant hosts decreased further with progress of infection. In the infected resistant hosts the concentrations of zeatin/zeatinriboside were the maximum among the four identified cytokinins. The pathogen is also capable of secreting cytokinins as evident from quantification of cytokinins in culture filtrate extracts using HPLC. Since detached leaves were used in the experiments the increase/decrease of various cytokinin levels may be attributed to pathogen influence. The increase in cytokinin levels in the susceptible host may be aiding the growth of the pathogen on one hand, while the decrease in the infected resistant host may signal the host to activate defenses against a potential pathogen at the early stage of infection.


Assuntos
Citocininas/metabolismo , Fungos/patogenicidade , Hordeum/microbiologia , Doenças das Plantas/microbiologia , Zea mays/microbiologia , Autorradiografia , Cromatografia Líquida de Alta Pressão , Citocininas/imunologia , Fungos/fisiologia
14.
Hybridoma ; 16(5): 479-83, 1997 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9388032

RESUMO

Three monoclonal antibodies (all IgG1) were prepared against the plant cytokinin dihydrozeatin riboside (diH[9R]Z) and characterized for suitability in the isolation and quantification of dihydrozeatin-type phytohormones. These antibodies detected as little as 5-10 pg of the homologous cytokinin when used in both competitive and noncompetitive immunoassays and each had characteristic crossreactivity with structurally-related cytokinins. One antibody was used to quantify HPLC-purified diH[9R]Z recovered from wheat tissue. The same antibody also was linked to an insoluble support for use in affinity purification of a mixture of cytokinins. These antibodies will be useful for purification and quantification of dihydrozeatin and its 9-riboside and 9-glucoside in plant tissue.


Assuntos
Anticorpos Monoclonais , Citocininas/imunologia , Animais , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Feminino , Hibridomas/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Oxirredutases/metabolismo , Triticum/química , Zeatina/metabolismo
15.
Ciênc. cult. (Säo Paulo) ; 46(5/6): 386-93, Sept.-Dec. 1994. ilus, graf
Artigo em Inglês | LILACS | ID: lil-199868

RESUMO

Cytokines are soluble polypeptides whose primary function is signalling from cell to cell. Within the immune system, cytokines function in a complex network, and are responsible for proper development and differentiation of cells and organs, as well as for controlling the humoral and cellular responses. Interferons (IFNs), best known for their antiviral activity, are cytokines that can modulate various functions of the immune system. In this review some aspects of the interactions between IFNs and other cytokines will be presented. In considering IFNs in the net, we will discuss their interations with other cytokines as well as the role of the transcription factor IRF-1 as a candidate for linking the cytokine network. To understand the immune system having IFNs out of the net, we have generated some "knock-out"mice deleted for specific components of the interferon system. These animals proved to be an important tool to clarify the role of these cytokines in the mechanism of defense and development of the immune system.


Assuntos
Animais , Antivirais/imunologia , Interferons/imunologia , Citocininas/imunologia , Sistema Imunitário , Camundongos , Fatores de Transcrição
16.
Rev. Soc. Bras. Med. Trop ; 25(2): 125-34, abr.-jun. 1992.
Artigo em Inglês | LILACS | ID: lil-141196

RESUMO

O estudo da resposta imune de pacientes com esquistossomose progride em funçäo do avanço tecnológico, apesar das dificuldades de manipulaçäo in vivo deste complexo sistema parasita-hospedeiro. A ênfase nos estudos tem sido mais freqüentemente dirigida para comparaçöes entre grupos característicos de indivíduos, tais como infectado/näo infectado, reinfectado/näo reinfectado, assintomático/hepato-esplênico, com intensidade de infecçäo alta/baixa, etc. Baseado nessas comparaçöes razoáveis com relaçäo à regulaçäo imunológica, susceptibilidade e resistência e até mesmo consideraçöes sôbre mecanismos, que têm sido mais apropriadamente analisados, entretanto, em sistemas experimentais. Tais estudos têm como finalidade a compreensäo das causas e eventos que levam à morbidade e ao desenvolvimento de uma vacina humana anti-esquistosoma


Assuntos
Humanos , Animais , Schistosoma mansoni/imunologia , Anticorpos Anti-Helmínticos/imunologia , Antígenos de Helmintos/imunologia , Citocininas/imunologia , Leucócitos Mononucleares/imunologia , Reações Antígeno-Anticorpo/imunologia , Recidiva , Schistosoma mansoni/imunologia
17.
Bioconjug Chem ; 3(1): 14-9, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1616944

RESUMO

An original procedure which preserves the structure of the sugar ring is described to link a plant hormone as N6-isopent-2-enyladenosine [( 9R]iP) onto a protein carrier to prepare a more specific immunogen. This cytokinin is bound to bovine serum albumin (BSA) and ovalbumin by a five-step procedure. These [9R]iP-protein conjugates have a maximal absorption at 269 nm and show molar ratios of hormone bound to proteins in the range of 12:1 and 18:1 for BSA and ovalbumin, respectively. Polyclonal antibodies were raised in rabbits against [9R]iP-BSA and were purified by affinity chromatography. Titers and specificity of the antisera and purified antibodies were determined by ELISA and RIA. These antibodies are highly specific for [9R]iP and do not cross-react with zeatin and ribosylzeatin. An immunoaffinity matrix was prepared with a capacity of 1 microgram of [9R]iP/mL of gel.


Assuntos
Anticorpos/imunologia , Citocininas/imunologia , Isopenteniladenosina/imunologia , Ovalbumina/imunologia , Soroalbumina Bovina/imunologia , Animais , Anticorpos/isolamento & purificação , Especificidade de Anticorpos , Cromatografia de Afinidade , Reações Cruzadas , Citocininas/química , Ensaio de Imunoadsorção Enzimática , Isopenteniladenosina/química , Ovalbumina/química , Coelhos , Soroalbumina Bovina/química , Espectrofotometria Ultravioleta
18.
Mem. Inst. Oswaldo Cruz ; 87(supl.5): 105-9, 1992.
Artigo em Inglês | LILACS | ID: lil-128429

RESUMO

American mucocutaneous leishmaniasis is a granulomatous disease clinically characterized by ulcerated skin lesions that can regress spontaneously. A small percentage of the affected individuals can however develop a severe destruction of the nasal, oral, pharyngeal and/or laryngeal mucous membranes many years after the healing of the primary lesion. The human immune response to the infection and the possible mechanisms underlying the pathogenesis of the disease, determining either the self-healing or the development of chronic and destructive mucosal lesions, are discussed


Assuntos
Citocininas/imunologia , Leishmaniose Mucocutânea/imunologia , Linfócitos T/imunologia
19.
Nucleic Acids Res ; 13(16): 5833-42, 1985 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-3929232

RESUMO

Isopentenyl adenosine antibodies useful in the investigations of the "cytokinin" functions of isopentenyl adenosine were purified by affinity chromatography. Using different affinity columns, the antibodies were purified to near complete purity. Analyses of the purified proteins revealed the presence of isopentenyl adenosine binding proteins in normal rabbit serum, which presence supports a suggested role for isopentenyl adenosine and its related compounds in animal cell division in vivo.


Assuntos
Adenina/análogos & derivados , Anticorpos/isolamento & purificação , Citocininas/imunologia , Reguladores de Crescimento de Plantas/imunologia , Adenina/análise , Animais , Cromatografia de Afinidade/métodos , Eletroforese em Gel de Poliacrilamida , Imunodifusão , Isopenteniladenosina , Coelhos/imunologia , Soroalbumina Bovina
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...