RESUMO
This corrects the article DOI: 10.1103/PhysRevLett.117.082503.
RESUMO
We present an improved search for neutrinoless double-beta (0νßß) decay of ^{136}Xe in the KamLAND-Zen experiment. Owing to purification of the xenon-loaded liquid scintillator, we achieved a significant reduction of the ^{110m}Ag contaminant identified in previous searches. Combining the results from the first and second phase, we obtain a lower limit for the 0νßß decay half-life of T_{1/2}^{0ν}>1.07×10^{26} yr at 90% C.L., an almost sixfold improvement over previous limits. Using commonly adopted nuclear matrix element calculations, the corresponding upper limits on the effective Majorana neutrino mass are in the range 61-165 meV. For the most optimistic nuclear matrix elements, this limit reaches the bottom of the quasidegenerate neutrino mass region.
RESUMO
Mycobacteria are among the most common causes of hypersensitivity pneumonitis (HP), but controversy persists with regard to the involvement of the infectious potency of the organism in mycobacterial HP (hot tub lung). This study aimed to establish a mouse model of hot tub lung to clarify its pathophysiology. Mice were exposed intranasally to formalin-killed Mycobacterium avium from a patient with hot tub lung (HP strain) or chronic pulmonary infection (non-HP strain), and bronchoalveolar lavage fluids and lung tissues were evaluated for allergic inflammation. Dead M. avium HP strain, but not non-HP strain, elicited marked HP-like pulmonary inflammation in wild-type mice. Although the inflammation was induced in mice lacking CD4 or CD8, the induction of HP-like responses was prevented in mice lacking myeloid differentiation factor (MyD)88 or Toll-like receptor (TLR)9. Cultured lung CD11c+ cells responded to M. avium in a TLR9-dependent manner, and reconstitution of TLR9-/- mice with lung CD11c+ cells from wild-type mice restored the inflammatory responses. Further investigation revealed that pulmonary exposure to M. avium HP strain increased the number of lung CD11b+ CD11c+ cells (dendritic cells) through TLR9 signalling. Our results provide evidence that hot tub lung develops via the mycobacterial engagement of TLR9-MyD88 signalling in lung CD11b+ dendritic cells independent of the mycobacterial infectious capacity.
Assuntos
Alveolite Alérgica Extrínseca/metabolismo , Alveolite Alérgica Extrínseca/microbiologia , Antígeno CD11b/biossíntese , Antígeno CD11c/biossíntese , Mycobacterium/metabolismo , Fator 88 de Diferenciação Mieloide/metabolismo , Receptor Toll-Like 9/metabolismo , Idoso , Animais , Feminino , Humanos , Imunidade Inata , Pulmão/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mycobacterium avium/metabolismo , Transdução de SinaisRESUMO
The Src family kinase Lyn initiates intracellular signal transduction by associating with a variety of immune receptors such as antigen receptor on B cells and high-affinity Fc receptor (FcR) for immunoglobulin Ig(E) (FcepsilonRI) on mast cells. Involvement of Lyn in the IgE-mediated immediate-type hypersensitivity is well documented, but the physiological significance of Lyn in IgG-dependent, type III low-affinity FcR for IgG (FcgammaRIII)-mediated responses is largely unknown. In this study, we generated a double-mutant mouse strain deficient in both type II FcR for IgG (FcgammaRIIB) and Lyn to exclude any involvement of inhibitory signaling by FcgammaRIIB, which otherwise downregulates FcgammaRIII-mediated cellular responses. FcgammaRIIB-deficient but Lyn-sufficient mice served as controls. The Lyn deficiency attenuated IgG-mediated systemic anaphylaxis in vivo, and significantly reduced calcium mobilization and degranulation responses of bone marrow-derived mast cells (BMMCs) in vitro. However, we found that either interleukin 4 or tumor necrosis factor alpha release by BMMCs was comparable to that from Lyn-deficient and control mice, and the reverse-passive Arthus reaction was equally induced in both mutant mice, indicating that Lyn is not involved in the onset of the IgG-mediated, FcgammaRIII-dependent late phase responses of mast cells. These findings provide us with insight into distinct signaling mechanisms in mast cells underlying the development of diverse pathologies as well as a therapeutic potential for selective treatment of allergic disorders.
Assuntos
Anafilaxia/imunologia , Reação de Arthus/imunologia , Receptores de IgG/metabolismo , Quinases da Família src/metabolismo , Animais , Antígenos CD/genética , Células da Medula Óssea/imunologia , Células da Medula Óssea/metabolismo , Cálcio/metabolismo , Células Cultivadas , Citocinas/biossíntese , Modelos Animais de Doenças , Haptenos/imunologia , Imunoglobulina E/imunologia , Imunoglobulina G/imunologia , Interleucina-4/metabolismo , Mastócitos/citologia , Mastócitos/imunologia , Mastócitos/metabolismo , Camundongos , Camundongos Mutantes , Ovalbumina/imunologia , Receptores de IgG/deficiência , Receptores de IgG/genética , Receptores de IgG/imunologia , Serotonina/metabolismo , Transdução de Sinais/imunologia , Fator de Necrose Tumoral alfa/metabolismo , Quinases da Família src/deficiência , Quinases da Família src/genéticaRESUMO
Paired immunoglobulin-like receptor B (PIR-B) (p91) molecule has been proposed to function as an inhibitory receptor in B cells and myeloid lineage cells. We demonstrate here that the cytoplasmic region of PIR-B is capable of inhibiting B cell activation. Mutational analysis of five cytoplasmic tyrosines indicate that tyrosine 771 in the motif VxYxxL plays the most crucial role in mediating the inhibitory signal. PIR-B-mediated inhibition was markedly reduced in the SH2-containing protein tyrosine phosphatases SHP-1 and SHP-2 double-deficient DT40 B cells, whereas this inhibition was unaffected in the inositol polyphosphate 5'-phosphatase SHIP-deficient cells. These data demonstrate that PIR-B can negatively regulate B cell receptor activation and that this PIR-B-mediated inhibition requires redundant functions of SHP-1 and SHP-2.
Assuntos
Linfócitos B/imunologia , Ativação Linfocitária , Proteínas Tirosina Fosfatases/metabolismo , Receptores de Antígenos de Linfócitos B/antagonistas & inibidores , Receptores Imunológicos/metabolismo , Antígenos CD/metabolismo , Células da Medula Óssea/imunologia , Cálcio/metabolismo , Análise Mutacional de DNA , Peptídeos e Proteínas de Sinalização Intracelular , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases , Monoéster Fosfórico Hidrolases/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 11 , Proteína Tirosina Fosfatase não Receptora Tipo 6 , Receptores de IgG/metabolismo , Transdução de SinaisRESUMO
The combination of hemorrhagic pneumonitis and rapidly progressive glomerulonephritis is a characteristic feature of Goodpasture's syndrome (GPS), an autoimmune disease resulting from the interaction of pathogenic anti-collagen type IV (C-IV) antibodies with alveolar and glomerular basement membranes. Lack of a suitable animal model for this fatal disease has hampered both a basic understanding of its etiology and the development of therapeutic strategies. We now report a novel model for GPS using mice deficient in a central regulatory receptor for immunoglobulin (Ig)G antibody expression and function, the type IIB Fc receptor for IgG (FcgammaRIIB). Mutant mice immunized with bovine C-IV reproducibly develop massive pulmonary hemorrhage with neutrophil and macrophage infiltration and crescentic glomerulonephritis. The distinctive linear, ribbon-like deposition of IgG immune complex seen in GPS was observed along the glomerular and tubulointerstitial membranes of diseased animals. These results highlight the role of FcgammaRIIB in maintaining tolerance and suggest that it may play a role in the pathogenesis of human GPS.
Assuntos
Doença Antimembrana Basal Glomerular/imunologia , Antígenos CD/genética , Colágeno/imunologia , Modelos Animais de Doenças , Camundongos Mutantes/imunologia , Receptores de IgG/genética , Animais , Doença Antimembrana Basal Glomerular/genética , Autoanticorpos/sangue , Hemorragia , Glomérulos Renais/patologia , Pulmão/patologia , CamundongosRESUMO
Autoantibodies and immune complexes are major pathogenic factors in autoimmune injury, responsible for initiation of the inflammatory cascade and its resulting tissue damage. This activation results from the interaction of immunoglobulin (Ig)G Fc receptors containing an activation motif (ITAM) with immune complexes (ICs) and cytotoxic autoantibodies which initiates and propagates an inflammatory response. In vitro, this pathway can be interrupted by coligation to FcgammaRIIB, an IgG Fc receptor containing an inhibitory motif (ITIM). In this report, we describe the in vivo consequences of FcgammaRII deficiency in the inflammatory response using a mouse model of IC alveolitis. At subthreshold concentrations of ICs that fail to elicit inflammatory responses in wild-type mice, FcgammaRII-deficient mice developed robust inflammatory responses characterized by increased hemorrhage, edema, and neutrophil infiltration. Bronchoalveolar fluids from FcgammaRII-/- stimulated mice contain higher levels of tumor necrosis factor and chemotactic activity, suggesting that FcgammaRII deficiency lowers the threshold of IC stimulation of resident cells such as the alveolar macrophage. In contrast, complement- and complement receptor-deficient mice develop normal inflammatory responses to suprathreshold levels of ICs, while FcRgamma-/- mice are completely protected from inflammatory injury. An inhibitory role for FcgammaRII on macrophages is demonstrated by analysis of FcgammaRII-/- macrophages which show greater phagocytic and calcium flux responses upon FcgammaRIII engagement. These data reveal contrasting roles for the cellular receptors for IgG on inflammatory cells, providing a regulatory mechanism for setting thresholds for IC sensitivity based on the ratio of ITIM to ITAM FcgammaR expression. Exploiting the FcgammaRII inhibitory pathway could thus provide a new therapeutic approach for modulating antibody-triggered inflammation.
Assuntos
Complexo Antígeno-Anticorpo/imunologia , Inflamação/imunologia , Receptores de IgG/imunologia , Animais , Líquido da Lavagem Broncoalveolar/citologia , Quimiocinas/metabolismo , Complemento C3/genética , Complemento C3/imunologia , Citocinas/metabolismo , Edema/patologia , Macrófagos Alveolares/imunologia , Camundongos , Camundongos Transgênicos , Neutrófilos/metabolismo , Fagocitose/imunologia , Alvéolos Pulmonares/patologia , Receptores de IgG/genéticaRESUMO
Autoimmune diseases, like rheumatoid arthritis, result from a dysregulation of the immune response culminating in hyperactivation of effector cells leading to immune-mediated injury. To maintain an appropriate immune response and prevent the emergence of autoimmune disease, activation signals must be regulated by inhibitory pathways. Biochemical and genetic studies indicate that the type IIB low-affinity receptor for immunoglobulin (Ig)G (FcgammaRIIB) inhibits cellular activation triggered through antibody or immune complexes and may be an important component in preventing the emergence of autoimmunity. To investigate the role of FcgammaRIIB in the development of type II collagen (CII)-induced arthritis (CIA), a model for rheumatoid arthritis in humans, we have examined its contribution in determining the susceptibility to CIA in the nonpermissive H-2(b) haplotype. H-2(b) mice immunized with bovine CII do not develop appreciable disease. In contrast, immunization of the FcgammaRIIB-deficient, H-2(b) mice with bovine CII induced CIA at an incidence of 42.2%. The maximal arthritis index of the FcgammaRIIB-deficient mice developing CIA (6.9 +/- 3.6) was comparable to that of DBA/1 mice (8.6 +/- 1.9), an H-2(q) strain susceptible for CIA induction. IgG1, IgG2a, and IgG2b antibody responses against CII were elevated in the FcgammaRIIB-deficient animals, especially in those mice showing arthritis, but less pronounced than DBA/1 mice. Histological examinations of the arthritic paws from FcgammaRIIB-deficient mice revealed that cartilage was destroyed and bone was focally eroded in association with marked lymphocyte and monocyte/macrophage infiltration, very similar to the pathologic findings observed in DBA/1 mice. These results indicate that a nonpermissive H-2(b) haplotype can be rendered permissive to CIA induction through deletion of FcgammaRIIB, suggesting that FcgammaRIIB plays a critical role in suppressing the induction of CIA.
Assuntos
Antígenos CD/metabolismo , Artrite Reumatoide/imunologia , Colágeno/farmacologia , Antígenos H-2/imunologia , Receptores de IgG/metabolismo , Animais , Anticorpos/sangue , Autoimunidade/imunologia , Cartilagem/patologia , Bovinos , Colágeno/imunologia , Modelos Animais de Doenças , Extremidades/patologia , Interleucina-1/metabolismo , Macrófagos Peritoneais/imunologia , Camundongos , Camundongos KnockoutRESUMO
It is widely accepted that immunoglobulin (Ig)E triggers immediate hypersensitivity responses by activating a cognate high-affinity receptor, FcepsilonRI, leading to mast cell degranulation with release of vasoactive and proinflammatory mediators. This apparent specificity, however, is complicated by the ability of IgE to bind with low affinity to Fc receptors for IgG, FcgammaRII and III. We have addressed the in vivo significance of this interaction by studying IgE-mediated passive systemic anaphylaxis in FcgammaR-deficient mice. Mice deficient in the inhibitory receptor for IgG, FcgammaRIIB, display enhanced IgE-mediated anaphylactic responses, whereas mice deficient in an IgG activation receptor, FcgammaRIII, display a corresponding attenuation of IgE-mediated responses. Thus, in addition to modulating IgG-triggered hypersensitivity responses, FcgammaRII and III on mast cells are potent regulators of IgE-mediated responses and reveal the existence of a regulatory pathway for IgE triggering of effector cells through IgG Fc receptors that could contribute to the etiology of the atopic response.
Assuntos
Anafilaxia/imunologia , Antígenos CD/imunologia , Imunoglobulina E/imunologia , Imunoglobulina G/imunologia , Receptores de IgG/imunologia , Animais , Antígenos CD/genética , Antígenos CD/metabolismo , Temperatura Corporal , Células da Medula Óssea , Histocitoquímica , Hipersensibilidade/etiologia , Hipersensibilidade/imunologia , Íleo/imunologia , Íleo/patologia , Mastócitos/imunologia , Camundongos , Camundongos Knockout , Ovalbumina , Receptores de IgG/deficiência , Receptores de IgG/genética , Receptores de IgG/metabolismoRESUMO
BACKGROUND: We previously reported that a faecal cyclooxygenase-2 (COX-2) mRNA assay was useful for identifying colorectal cancer (CRC). This study sought to investigate the factors that contribute to faecal COX-2 mRNA expression in subjects with CRC. METHODS: The study cohort comprised 78 patients with CRC and 36 control subjects. The expressions of COX-2, beta-2-microglobulin (B2M), carcinoembryonic antigen (CEA), E-cadherin (E-cad), and CD45 mRNA in faeces and COX-2 mRNA expression in tissue were determined by quantitative real-time RT-PCR. RESULTS: The level of faecal expression of COX-2 mRNA in CRC was significantly higher than that in controls. A significant correlation was found between faecal COX-2 mRNA expression and faecal B2M, CEA, E-cad, or CD45 mRNAs, markers of exfoliated total cells, colonocytes, and leukocytes, respectively. A significant correlation was found between the expression of COX-2 mRNA in faeces and tumour surface area, COX-2 mRNA expression in primary tumour. There was no difference in faecal COX-2 mRNA expression between proximal CRC and distal CRC. CONCLUSION: COX-2 mRNA expression in faeces seems to originate from tumour lesion and to be affected by factors such as the number of exfoliated cells, exfoliation of inflammatory cells, COX-2 mRNA expression in tumour, and tumour size.
Assuntos
Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Ciclo-Oxigenase 2/genética , Fezes/química , RNA Mensageiro/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/metabolismo , Caderinas/genética , Caderinas/metabolismo , Antígeno Carcinoembrionário/genética , Antígeno Carcinoembrionário/metabolismo , Estudos de Casos e Controles , Estudos de Coortes , Colo/metabolismo , Colo/patologia , Neoplasias Colorretais/metabolismo , Ciclo-Oxigenase 2/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , RNA Mensageiro/metabolismo , Reto/metabolismo , Reto/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Taxa de Sobrevida , Adulto Jovem , Microglobulina beta-2/genética , Microglobulina beta-2/metabolismoRESUMO
Immunoglobulins (Igs) play important immunomodulatory effects on allergic asthma. Among these, IgG has been reported to regulate allergic inflammation in previous studies about immunotherapy and intravenous immunoglobulin therapy. In this study, to examine the immunomodulatory mechanisms of IgG and FcRs we evaluated the effects of intravenous (i.v.) rabbit IgG administration (IVIgG) on allergic airway inflammation and lung antigen-presenting cells (APCs) in a murine model of ovalbumin (OVA) sensitization and challenge. In OVA-challenged mice, IVIgG attenuated airway eosinophilia, airway hyperresponsiveness and goblet cell hyperplasia and also inhibited the local T helper type (Th) 2 cytokine levels. Additionally, IVIgG attenuated the proliferation of OVA-specific CD4(+) T cells transplanted into OVA-challenged mice. Ex vivo co-culture with OVA-specific CD4(+) cells and lung CD11c(+) APCs from mice with IVIgG revealed the attenuated transcription level of Th2 cytokines, suggesting an inhibitory effect of IVIgG on CD11c(+) APCs to induce Th2 response. Next, to analyse the effects on Fcγ receptor IIb and dendritic cells (DCs), asthmatic features in Fcγ receptor IIb-deficient mice were analysed. IVIgG failed to attenuate airway eosinophilia, airway inflammation and goblet cell hyperplasia. However, the lacking effects of IVIgG on airway eosinophilia in Fcγ receptor IIb deficiency were restored by i.v. transplantation of wild-type bone marrow-derived CD11c(+) DCs. These results demonstrate that IVIgG attenuates asthmatic features and the function of lung CD11c(+) DCs via Fcγ receptor IIb in allergic airway inflammation. Targeting Fc portions of IgG and Fcγ receptor IIb on CD11c(+) DCs in allergic asthma is a promising therapeutic strategy.
Assuntos
Asma/terapia , Antígeno CD11c/metabolismo , Células Dendríticas/efeitos dos fármacos , Imunoglobulina G/farmacologia , Imunoglobulinas Intravenosas/farmacologia , Receptores de IgG/genética , Transferência Adotiva , Animais , Apresentação de Antígeno/efeitos dos fármacos , Apresentação de Antígeno/imunologia , Asma/imunologia , Asma/patologia , Asma/fisiopatologia , Hiper-Reatividade Brônquica/fisiopatologia , Hiper-Reatividade Brônquica/prevenção & controle , Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/citologia , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Contagem de Células , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/imunologia , Proliferação de Células , Citocinas/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Células Dendríticas/transplante , Modelos Animais de Doenças , Eosinófilos/citologia , Feminino , Imunoglobulina E/sangue , Imunoglobulina G/uso terapêutico , Imunoglobulinas Intravenosas/uso terapêutico , Fatores Imunológicos/farmacologia , Fatores Imunológicos/uso terapêutico , Inflamação/imunologia , Inflamação/patologia , Inflamação/prevenção & controle , Camundongos , Camundongos Endogâmicos C57BL , Ovalbumina/imunologia , Organismos Livres de Patógenos Específicos , Células Th2/imunologiaRESUMO
BACKGROUND: House dust mites produce serine and cysteine proteases. Mite-derived proteases have been suggested to be involved in the pathogenesis of allergies; however, whether mite-derived serine protease activity can stimulate keratinocytes remains unknown. METHODS: We examined the activation of primary human keratinocytes by serine protease-rich extract of whole mite culture and compared with that by recombinant group 1 allergens (rDer f 1 and rDer p 1), which exclusively exhibit cysteine protease activity. RESULTS: Protease activity of whole mite culture extract (WCE), rDer f 1 and rDer p 1 induced the release of IL-8 and granulocyte-macrophage colony-stimulating factor. Protease activity of WCEs induced a significant upregulation of their mRNA expression but rDer f 1 had much less effect. Protease activity of the WCE stimulated intracellular Ca(2+) mobilization but rDer f 1 and rDer p 1 did not. The mobilization induced by agonists for the human protease-activated receptor (PAR)-2, an agonist peptide or trypsin, was diminished by pre-incubation of keratinocytes with WCE. rDer f 1 inefficiently cleaved a synthetic N-terminal peptide of PAR-2 at different sites from trypsin, but the resultant peptides did not stimulate the release of interleukin-8. CONCLUSIONS: The results suggest that mite-derived serine protease activity may contribute to the pathogenesis of atopic dermatitis by activating keratinocytes via PAR-2 activation but cysteine protease activity of Der f 1 and Der p 1 acts via another mechanism.
Assuntos
Dermatite Atópica/imunologia , Queratinócitos/imunologia , Pyroglyphidae/enzimologia , Receptor PAR-2/metabolismo , Serina Proteases/imunologia , Animais , Antígenos de Dermatophagoides/metabolismo , Antígenos de Dermatophagoides/farmacologia , Proteínas de Artrópodes , Cálcio/metabolismo , Células Cultivadas , Cisteína Endopeptidases , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Humanos , Interleucina-8/metabolismo , Queratinócitos/efeitos dos fármacos , Peptídeos/farmacologia , Pyroglyphidae/imunologia , RNA Mensageiro/metabolismo , Receptor PAR-2/agonistas , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia , Serina Proteases/farmacologiaRESUMO
Recombination activating genes (RAG-1 and RAG-2), involved in V(D)J rearrangement of immunoglobulin genes, have been thought to be expressed only in immature stages of B-cell development. However, RAG-1 and RAG-2 transcripts were found to be reexpressed in mature mouse B cells after culture with interleukin-4 in association with several different co-stimuli. Reexpression was also detected in draining lymph nodes from immunized mice. RAG-1 and RAG-2 proteins could be detected by immunofluorescence microscopy in the nuclei of B cells cultured in vitro and in the germinal centers of draining lymph nodes. These findings suggest that RAG gene products play a heretofore unsuspected role in mature B cells.
Assuntos
Linfócitos B/metabolismo , Proteínas de Ligação a DNA , Expressão Gênica , Genes RAG-1 , Proteínas de Homeodomínio , Ativação Linfocitária , Proteínas/genética , Animais , Linfócitos B/imunologia , Núcleo Celular/metabolismo , Células Cultivadas , Centro Germinativo/metabolismo , Switching de Imunoglobulina , Interleucina-4/farmacologia , Interleucinas/farmacologia , Lipopolissacarídeos/farmacologia , Linfonodos/metabolismo , Camundongos , Camundongos Endogâmicos C3H , Microscopia de Fluorescência , Biossíntese de ProteínasRESUMO
BACKGROUND: Hydrogen (H2) and carbon monoxide (CO) gas are both reported to reduce reactive oxygen species and alleviate tissue ischemia-reperfusion (I-R) injury. The present study was conducted to evaluate the effects of a mixture of H2 gas and CO gas (dual gas) in comparison with hydrogen gas (H2: 2%) alone on I-R renal injury (composition of dual gas; N2: 77.8%; O2: 20.9%; H2: 1.30%; CO: 250 parts per million). METHODS: Adult male Sprague-Dawley rats (body weight 250-280 g) were divided into 5 groups: (1) sham operation control, (2) dual gas inhalation (dual treatment) without I-R treatment, (3) I-R renal injury, (4) H2 gas alone inhalation (H2 treatment) with I-R renal injury, and (5) dual treatment with I-R renal injury. I-R renal injury was induced by clamping the left renal artery and vein for 45 minutes followed by reperfusion, and then contralateral nephrectomy was performed 2 weeks later. Renal function was markedly decreased at 24 hours after reperfusion, and thereafter the effects of dual gas were assessed by histologic examination and determination of the superoxide radical, together with functional and molecular analyses. RESULTS: Pathologic examination of the kidney of I-R rats revealed severe renal damage. Importantly, cytoprotective effects of the dual treatment in comparison with H2 treatment and I-R renal injury were observed in terms of superoxide radical scavenging activity and histochemical features. Rats given dual treatment and I-R renal injury showed significant decreases in blood urea nitrogen. Increased expression of several inflammatory cytokines (tumor necrosis factor-α, interleukin-6, intracellular adhesion molecule-1, nuclear factor-κB, hypoxia inducible factor-1α, and heme oxygenase-1) was attenuated by the dual treatment. CONCLUSIONS: Dual gas inhalation decreases oxidative stress and markedly improves I-R-induced renal injury.
Assuntos
Antioxidantes/farmacologia , Monóxido de Carbono/farmacologia , Hidrogênio/farmacologia , Nefrectomia , Estresse Oxidativo/efeitos dos fármacos , Traumatismo por Reperfusão/tratamento farmacológico , Administração por Inalação , Animais , Nitrogênio da Ureia Sanguínea , Citocinas/metabolismo , Quimioterapia Combinada , Rim/efeitos dos fármacos , Rim/cirurgia , Testes de Função Renal , Masculino , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Artéria Renal/cirurgia , Traumatismo por Reperfusão/etiologiaRESUMO
A major problem with allergen-specific immunotherapy involving repeated injection of allergens is the risk of an anaphylactic reaction. We engineered the major house dust mite allergen, Der f 2, to reduce its capacity to induce skin test reactivity and histamine release from peripheral blood basophils in allergic patients. The engineered allergen, in which the disulfide bond that linked the N- and C-terminal sequences of Der f 2 was disrupted, retained T-cell epitopes essential for immunotherapy and ability to stimulate T-cell proliferation. Such engineered allergens are potentially useful for safer and more effective immunotherapy for allergies.
Assuntos
Alérgenos/genética , Antígenos/genética , Dessensibilização Imunológica , Engenharia Genética , Glicoproteínas/genética , Ácaros/imunologia , Alérgenos/imunologia , Alérgenos/metabolismo , Animais , Antígenos/imunologia , Antígenos/metabolismo , Antígenos de Dermatophagoides , Basófilos/efeitos dos fármacos , Basófilos/imunologia , Divisão Celular/efeitos dos fármacos , Cisteína/genética , Cisteína/metabolismo , Dissulfetos/química , Dissulfetos/metabolismo , Epitopos de Linfócito T/imunologia , Glicoproteínas/imunologia , Glicoproteínas/metabolismo , Liberação de Histamina/efeitos dos fármacos , Humanos , Hipersensibilidade/imunologia , Hipersensibilidade/terapia , Imunoglobulina E/metabolismo , Mutagênese Sítio-Dirigida , Testes CutâneosRESUMO
Several mouse lymphoid cell lines were efficiently transfected with plasmid DNA by a novel method combining DEAE-dextran-mediated DNA uptake and osmotic shock procedure. The cells were first incubated with DNA-DEAE-dextran complex, treated with hypertonic Tris-HCl buffer containing 0.5 M sucrose and 10% poly(ethylene glycol), and then exposed to hypotonic RPMI 1640 medium. This transfection protocol exhibited maximal frequencies of 0.3% and 3.10(-5) for transient gene expression and stable transformation in P3-NSI/1-Ag4-1 cells, respectively.
Assuntos
DNA/genética , Transfecção , Animais , Linhagem Celular , DEAE-Dextrano , Eletroforese em Gel de Ágar , Expressão Gênica , Camundongos , Pressão OsmóticaRESUMO
The expression of genes introduced into various mammalian cell lines was enhanced by raising the temperature of the cells to 42 degrees C for a few hours after DNA transfection. This heat treatment resulted in an up to 10-fold increase in the frequency of the cells that transiently expressed a foreign gene such as that of beta-galactosidase, whereas it had only a limited enhancing effect on the development of stable transformants. By immunotitration analysis, it was confirmed that the enhanced expression of beta-galactosidase activity correlated well with the increase of the enzyme protein. This procedure may have an applicability for augmenting the frequency of transient gene expression in many cell types.
Assuntos
Temperatura Alta , Transfecção , Animais , Linhagem Celular , Escherichia coli/enzimologia , Escherichia coli/genética , Expressão Gênica , Vetores Genéticos , Imunoquímica/métodos , Plasmídeos , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , beta-Galactosidase/biossíntese , beta-Galactosidase/genéticaRESUMO
Cytidylate cyclase activity, which enzymatically converts cytidine 5'-triphosphate (CTP) to cytidine 3',5'-cyclic monophosphate (cyclic CMP), has been demonstrated in mouse tissue homogenates by use of a highly sensitive enzyme immunoassay (EIA) specific for cyclic CMP. Cyclic CMP formation is dependent on the amount of homogenate and on the incubation time. Although the enzyme activity was detected at wide ranges of pH from 6.8 to 11.5, the maximal activity was observed at around pH 9.4. The optimal temperature was 37 degrees C. Cytidylate cyclase activity was almost completely lost if the homogenates were heated at 90 degrees C for 3 min prior to use. The enzyme reaction exhibited typical Michaelis-Menten kinetics with an apparent Km for CTP of approx. 0.31 mM. Cyclic CMP formation was greatly enhanced with 4 mM Mn2+, Mg2+, Co2+; Mn2+ was the most effective. Fe2+ and Ca2+ were without effect. Cu2+ and Zn2+ at a concentration of 0.1 to 0.5 mM were inhibitory to Mn2+-dependent activity. Moreover, the enzyme activity was inhibited by several nucleotides including ATP, ADP, 5'-AMP, and GTP. Cytidylate cyclase activity was found to be present in all homogenates from a variety of mouse tissues examined except heart, with the highest level found in brain, and the lowest in liver.
Assuntos
CMP Cíclico/metabolismo , Citidina Trifosfato/metabolismo , Nucleotídeos de Citosina/metabolismo , Liases/metabolismo , Fósforo-Oxigênio Liases , Animais , Encéfalo/enzimologia , Cátions Bivalentes , Cobalto/farmacologia , Feminino , Temperatura Alta , Concentração de Íons de Hidrogênio , Técnicas Imunoenzimáticas , Cinética , Liases/antagonistas & inibidores , Magnésio/farmacologia , Manganês/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Especificidade por Substrato , Temperatura , Distribuição TecidualRESUMO
B cell epitopes of the major house dust mite allergen Der f 2 from Dermatophagoides farinae were analysed using deletion mutants of Der f 2 expressed as fusion proteins in Escherichia coli. The reactivities of these partial Der f 2 molecules to human anti-mite IgE antibodies in atopic patients and to murine anti-Der f2 monoclonal antibodies (mAbs) were examined by immunoblotting. A C-terminal deletion mutant of Der f 2, 1-123, had almost the same reactivity to human IgE as the whole Der f 2 (1-129) and an N-terminal deletion mutant of Der f 2 (25-129) still had weak reactivity. On the other hand, in two deleted Der f 2 molecules, 1-120 and 30-129, reactivity was lost in spite of long overlapping sequences. These results suggest that the human IgE antibodies to Der f 2 in atopic patient sera recognize the conformational structures dependent on the tertiary structure of Der f 2, including disulfide bond formations, rather than the contiguous sequences of amino acids. The sequences 1-24, 25-29 and 121-123 were revealed as the minimum N- and C- terminal amino acid sequences required for IgE binding. Contrastingly, all three murine mAbs bound to the smaller deletion mutants, 1-90 and 67-129, suggesting that the cores of the epitopes for these mAbs exist in the 24 amino acid sequence of Der f 2, 67-90 overlapping the sequential human IgE epitope on Der p 2, the equivalent allergen from Dermatophagoides pteronyssinus. These findings are important for the understanding of the antigenic structure of Der f 2 and for the manipulation of the allergen for immunotherapy.
Assuntos
Alérgenos/imunologia , Anticorpos Monoclonais/imunologia , Glicoproteínas/imunologia , Imunoglobulina E/química , Alérgenos/química , Sequência de Aminoácidos , Animais , Antígenos de Dermatophagoides , Mapeamento de Epitopos , Glicoproteínas/química , Humanos , Imunoglobulina E/metabolismo , Camundongos , Ácaros/imunologia , Ligação Proteica , Deleção de Sequência , Relação Estrutura-AtividadeRESUMO
Allergen-specific immunotherapy, in which repeated injections of allergens over prolonged periods are used to induce tolerance, has proven an effective treatment of allergy. A major side effect of allergen-specific immunotherapy is anaphylactic reaction. House dust mite allergens are major causative factors associated with various allergic diseases. Der f 2 is the major house dust mite allergen composed of 129 amino acid residues. Analysis using deletion mutants of Der f 2 suggested that T-cell epitopes of Der f 2 were multiple in mite-allergic patients. We found that some IgE epitopes were renatured by dialysis of a mixture of two denatured C- and N-terminal deletion mutants, 1-112 and 85-129 in 13 patients out of 14. On the other hand, IgE binding activity was negative in the separately dialyzed fragments and their mixture in each patient tested. Furthermore, we demonstrated that neither of the two separately prepared polypeptides induced in vivo skin prick test reactivity. These findings are important for improvement of T-cell targeting allergen-specific immunotherapy and development of monovalent IgE haptens. The use of combinations of overlapping non-anaphylactic fragments of allergen covering all of the T-cell epitopes achieves the removal of IgE reactivity, the cause of harmful anaphylactic reactions, without affecting the T-cell reactivity essential for immunotherapy, offering potentially safer and more effective treatment for allergic disease.