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1.
Transplant Proc ; 50(1): 250-258, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29407319

RESUMEN

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.


Asunto(s)
Antioxidantes/farmacología , Monóxido de Carbono/farmacología , Hidrógeno/farmacología , Nefrectomía , Estrés Oxidativo/efectos de los fármacos , Daño por Reperfusión/tratamiento farmacológico , Administración por Inhalación , Animales , Nitrógeno de la Urea Sanguínea , Citocinas/metabolismo , Quimioterapia Combinada , Riñón/efectos de los fármacos , Riñón/cirugía , Pruebas de Función Renal , Masculino , Ratas , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismo , Arteria Renal/cirugía , Daño por Reperfusión/etiología
3.
Phys Rev Lett ; 117(8): 082503, 2016 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-27588852

RESUMEN

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.

5.
Cell Death Dis ; 2: e198, 2011 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-21881600

RESUMEN

The Nogo receptor and paired immunoglobulin-like receptor B (PIR-B) are receptors for three myelin-derived axon-growth inhibitors, including myelin-associated glycoprotein (MAG). In this study, we report that the p75 receptor is required for the signal transduction of PIR-B, which interacted with p75 upon ligand binding. In addition, p75 was required for activation of Src homology 2-containing protein tyrosine phosphatase (SHP), which is induced by MAG binding to PIR-B. Mice carrying a mutation in the p75 gene showed promotion of axonal regeneration after optic nerve injury. Thus, our results indicate that p75 has a critical role in axon growth inhibition in specific neuronal tracts.


Asunto(s)
Axones/fisiología , Receptor de Factor de Crecimiento Nervioso/metabolismo , Receptores Inmunológicos/metabolismo , Animales , Células COS , Chlorocebus aethiops , Ratones , Ratones Endogámicos C57BL , Mutación , Glicoproteína Asociada a Mielina/metabolismo , Unión Proteica , Proteínas Tirosina Fosfatasas/química , Proteínas Tirosina Fosfatasas/metabolismo , Receptor de Factor de Crecimiento Nervioso/genética , Receptor trkB/metabolismo , Transducción de Señal , Dominios Homologos src
6.
Eur Respir J ; 38(3): 688-701, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21273385

RESUMEN

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.


Asunto(s)
Alveolitis Alérgica Extrínseca/metabolismo , Alveolitis Alérgica Extrínseca/microbiología , Antígeno CD11b/biosíntesis , Antígeno CD11c/biosíntesis , Mycobacterium/metabolismo , Factor 88 de Diferenciación Mieloide/metabolismo , Receptor Toll-Like 9/metabolismo , Anciano , Animales , Femenino , Humanos , Inmunidad Innata , Pulmón/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Mycobacterium avium/metabolismo , Transducción de Señal
7.
Clin Exp Immunol ; 162(2): 315-24, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20819092

RESUMEN

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.


Asunto(s)
Asma/terapia , Antígeno CD11c/metabolismo , Células Dendríticas/efectos de los fármacos , Inmunoglobulina G/farmacología , Inmunoglobulinas Intravenosas/farmacología , Receptores de IgG/genética , Traslado Adoptivo , Animales , Presentación de Antígeno/efectos de los fármacos , Presentación de Antígeno/inmunología , Asma/inmunología , Asma/patología , Asma/fisiopatología , Hiperreactividad Bronquial/fisiopatología , Hiperreactividad Bronquial/prevención & control , Líquido del Lavado Bronquioalveolar/química , Líquido del Lavado Bronquioalveolar/citología , Linfocitos T CD4-Positivos/citología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Recuento de Células , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/inmunología , Proliferación Celular , Citocinas/metabolismo , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Células Dendríticas/trasplante , Modelos Animales de Enfermedad , Eosinófilos/citología , Femenino , Inmunoglobulina E/sangre , Inmunoglobulina G/uso terapéutico , Inmunoglobulinas Intravenosas/uso terapéutico , Factores Inmunológicos/farmacología , Factores Inmunológicos/uso terapéutico , Inflamación/inmunología , Inflamación/patología , Inflamación/prevención & control , Ratones , Ratones Endogámicos C57BL , Ovalbúmina/inmunología , Organismos Libres de Patógenos Específicos , Células Th2/inmunología
8.
Colloids Surf B Biointerfaces ; 77(1): 18-21, 2010 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-20116978

RESUMEN

Properties of various carbon nanomaterials in bilirubin adsorption have been studied to develop a new adsorbent in the plasma apheresis. Carbon nanomaterials we used as adsorbents are single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), and single-walled carbon nanohorns (SWNHs). The adsorbent was mixed with a bilirubin solution, and the adsorption capacity was obtained by measuring the concentrations of residual bilirubin in the solution after the adsorption process. We found that the bundled MWCNTs exhibit the largest capacity in the saturated amount of adsorbed bilirubin among the examined materials, and that the oxidized SWNHs exhibit the fastest rate in the early stage of the adsorption. We also found that the amount of adsorbed bilirubin increases with an increase in the dispersibility of the adsorbent.


Asunto(s)
Bilirrubina/química , Nanotubos de Carbono , Adsorción , Cinética , Propiedades de Superficie
9.
Br J Cancer ; 102(5): 916-21, 2010 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-20145612

RESUMEN

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.


Asunto(s)
Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Ciclooxigenasa 2/genética , Heces/química , ARN Mensajero/genética , Adulto , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/metabolismo , Cadherinas/genética , Cadherinas/metabolismo , Antígeno Carcinoembrionario/genética , Antígeno Carcinoembrionario/metabolismo , Estudios de Casos y Controles , Estudios de Cohortes , Colon/metabolismo , Colon/patología , Neoplasias Colorrectales/metabolismo , Ciclooxigenasa 2/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , ARN Mensajero/metabolismo , Recto/metabolismo , Recto/patología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Tasa de Supervivencia , Adulto Joven , Microglobulina beta-2/genética , Microglobulina beta-2/metabolismo
11.
Allergy ; 64(9): 1366-74, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19416145

RESUMEN

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.


Asunto(s)
Dermatitis Atópica/inmunología , Queratinocitos/inmunología , Pyroglyphidae/enzimología , Receptor PAR-2/metabolismo , Serina Proteasas/inmunología , Animales , Antígenos Dermatofagoides/metabolismo , Antígenos Dermatofagoides/farmacología , Proteínas de Artrópodos , Calcio/metabolismo , Células Cultivadas , Cisteína Endopeptidasas , Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Humanos , Interleucina-8/metabolismo , Queratinocitos/efectos de los fármacos , Péptidos/farmacología , Pyroglyphidae/inmunología , ARN Mensajero/metabolismo , Receptor PAR-2/agonistas , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacología , Serina Proteasas/farmacología
12.
Colloids Surf B Biointerfaces ; 71(2): 255-9, 2009 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-19327971

RESUMEN

Bilirubin adsorption on carbon nanotube surfaces has been studied to develop a new adsorbent in the plasma apheresis. Powder-like carbon nanotubes were first examined under various adsorption conditions such as temperatures and initial concentrations of bilirubin solutions. The adsorption capacity was measured from the residual concentrations of bilirubin in the solution after the adsorption process using a visible absorption spectroscopy. We found that multi-walled carbon nanotubes (MWCNTs) exhibit greater adsorption capacity for bilirubin molecules than that of single-walled carbon nanotubes (SWCNTs). To guarantee the safety of the adsorbents, we fabricated carbon nanotube sheets in which leakage of CNTs to the plasma is suppressed. Since SWCNTs are more suitable for robust sheets, a complex sheet consisting of SWCNTs as the scaffolds and MWCNTs as the efficient adsorbents. CNT/polyaniline complex sheets were also fabricated. Bilirubin adsorption capacity of CNTs has been found to be much larger than that of the conventional materials because of their large surface areas and large adsorption capability for polycyclic compound molecules due to their surface structure similar to graphite.


Asunto(s)
Bilirrubina/química , Nanotubos de Carbono/química , Adsorción , Compuestos de Anilina/química , Nanotubos de Carbono/ultraestructura , Polvos , Espectrometría Raman , Factores de Tiempo
13.
Biochem Biophys Res Commun ; 324(4): 1340-5, 2004 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-15504361

RESUMEN

The squamous cell carcinoma antigen 1 (SCCA1) and SCCA2 are unique serpins that can inhibit cysteine proteinases. SQN-5, their mouse ortholog, has already been identified, and its inhibitory property has been characterized; however, its biological role has remained undefined. Furthermore, no other mouse homolog of SQN-5 has been known. We characterize three mouse members of SCCA-related molecules including SQN-5 in this article. Serpinb3a (SQN-5) and Serpinb3b, but not Serpinb3c, were functional, inhibiting both serine and cysteine proteinases with different inhibitory profiles due to the difference of two amino acids in their reactive site loops. Serpinb3a was ubiquitously expressed in most tissues, whereas expression of Serpinb3b was limited to keratinocytes. Keratinocytes secreted both SCCA-related proteins, Serpinb3a and Serpinb3b. These results indicate that Serpinb3a and Serpinb3b may play different roles by inhibiting intrinsic or extrinsic proteinases with different expression distributions and different inhibitory profiles.


Asunto(s)
Serpinas/genética , Serpinas/fisiología , Secuencia de Aminoácidos , Animales , Antígenos de Neoplasias/clasificación , Mapeo Cromosómico , Queratinocitos/metabolismo , Ratones , Datos de Secuencia Molecular , Alineación de Secuencia , Serpinas/química , Serpinas/clasificación
14.
J Immunol ; 167(6): 3427-34, 2001 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-11544335

RESUMEN

It has been shown that IgE binding to FcepsilonRI on mast cells results in increased FcepsilonRI expression, which in turn enhances IgE-dependent chemical mediator release from mast cells. Therefore, prevention of the IgE-mediated FcepsilonRI up-regulation would be a promising strategy for management of allergic disorders. However, the mechanism of IgE-mediated FcepsilonRI up-regulation has not been fully elucidated. In this study, we analyzed kinetics of FcepsilonRI on peritoneal mast cells and bone marrow-derived mast cells. In the presence of brefeldin A, which prevented transport of new FcepsilonRI molecules to the cell surface, levels of IgE-free FcepsilonRI on mast cells decreased drastically during culture, whereas those of IgE-bound FcepsilonRI were stable. In contrast, levels of FcgammaRIII on the same cells were stable even in the absence of its ligand, indicating that FcepsilonRI alpha-chain, but not beta- and gamma-chains, was responsible for the instability of IgE-free FcepsilonRI. As far as we analyzed, there was no evidence to support the idea that IgE binding to FcepsilonRI facilitated synthesis and/or transport of FcepsilonRI to the cell surface. Therefore, the stabilization and accumulation of FcepsilonRI on the cell surface through IgE binding appears to be the major mechanism of IgE-mediated FcepsilonRI up-regulation.


Asunto(s)
Membrana Celular/metabolismo , Inmunoglobulina E/farmacología , Mastocitos/efectos de los fármacos , Receptores de IgE/biosíntesis , Regulación hacia Arriba/efectos de los fármacos , Animales , Células de la Médula Ósea/efectos de los fármacos , Células de la Médula Ósea/metabolismo , Brefeldino A/farmacología , Estabilidad de Medicamentos , Humanos , Inmunoglobulina E/sangre , Inmunoglobulina E/inmunología , Inmunoglobulina E/metabolismo , Ligandos , Mastocitos/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Transgénicos , Unión Proteica , Subunidades de Proteína , Receptores de IgE/química , Receptores de IgE/genética , Proteínas Recombinantes de Fusión/farmacología , Transcripción Genética
15.
Immunol Rev ; 181: 215-22, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11513143

RESUMEN

Clones for murine paired immunoglobulin-like receptors (PIR) were first isolated as those coding for type I transmembrane glycoproteins with six immunoglobulin-like domains homologous to human Fc alphaR, bovine Fc gamma2R, and other related receptors. However, they turned out to bind neither IgA nor other immunoglobulins in the case of the ectopic expression on COS-1 fibroblastic cells. PIR-A and B are expressed on a wide variety of cells in the murine immune system, such as in B cells, mast cells, macrophages, and dendritic cells, mostly in a pairwise fashion. PIR-A requires homodimeric Fc receptor common gamma chain, which harbors an immunoreceptor tyrosine-based activation motif, for its efficient cell surface expression and for the delivery of activation signaling. In contrast, PIR-B contains immunoreceptor tyrosine-based inhibitory motifs (ITIMs) in its cytoplasmic portion and inhibits receptor-mediated activation signaling in vitro upon engagement with other activating-type receptors such as the antigen receptor on B cells and the high affinity Fc receptor for IgE on mast cells. ITIMs of PIR-B on macrophages and B cells have been shown to be constitutively phosphorylated in their tyrosine residues. Although the ligand for PIR still remains unknown, the transgenics and the gene-targeted mice will provide us with valuable information on their physiological roles in the immune regulation.


Asunto(s)
Receptores Inmunológicos/metabolismo , Animales , Evolución Biológica , Bovinos , Mapeo Cromosómico , Expresión Génica , Humanos , Ratones , Receptores Inmunológicos/química , Receptores Inmunológicos/genética , Transducción de Señal
16.
Hepatogastroenterology ; 48(40): 1206-8, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11490835

RESUMEN

An 84-year-old man presented with complaints of epigastric discomfort. Upper gastrointestinal series and endoscopy showed an elevated lesion at the posterior wall of greater curvature on the gastric fundus. Diagnosed as moderately differentiated tubular adenocarcinoma by biopsy, wedge resection and 4sa regional lymph node dissection were carried out. The tumor morphology showed type I with slight elevation, 2.5 x 1.7 cm in size; histological showed papillary, tubular, and solid formations having clear cytoplasm and large bizarre nuclei invading the deep submucosal layer (sm2). This case was evaluated as T1(sm) N0 M0 stage Ia early gastric cancer. In the 5th month after operation, multiple liver metastases were detected. He died of liver failure by rapid growth of metastatic tumors in the 6th month after operation. The serum alpha-fetoprotein level at recurrence was 1,900 ng/mL, and alpha-fetoprotein-positive cells were immunohistochemically detected in operative and liver biopsy specimens.


Asunto(s)
Neoplasias Hepáticas/secundario , Neoplasias Gástricas/metabolismo , alfa-Fetoproteínas/análisis , Anciano , Anciano de 80 o más Años , Resultado Fatal , Humanos , Inmunohistoquímica , Masculino , Neoplasias Gástricas/patología
17.
Biosci Biotechnol Biochem ; 65(7): 1601-9, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11515545

RESUMEN

Recently, we reported that introduction of mutations that induced conformational changes of the major mite allergen Der f 2 was an efficient strategy to reduce the allergenicity for safer allergen-specific immunotherapy. In this study, we evaluated another strategy, disruption of two independent IgE epitopes without inducing conformational change. We analyzed allergenicities of the wild-type Der f 2, two single mutants with a mutation at either of the two IgE-binding sites (K15A and K77A), and a double mutant with mutations at both of the sites (K15/77A). Purified recombinant forms of Der f 2 expressed in Escherichia coli had correct disulfide bonds, equivalent apparent molecular masses of approximately 15 kDa, and similar secondary structures. The mutants of Der f 2 had less IgE reactivities than the wild-type Der f 2 and reduced inhibitory activities for IgE-binding to the wild-type Der f 2. However, the mutations did not significantly reduce histamine-releasing activity.


Asunto(s)
Alérgenos/genética , Glicoproteínas/genética , Glicoproteínas/inmunología , Ácaros/genética , Ácaros/inmunología , Mutación , Alérgenos/química , Alérgenos/metabolismo , Animales , Antígenos Dermatofagoides , Basófilos/inmunología , Sitios de Unión/genética , Escherichia coli/genética , Glicoproteínas/química , Glicoproteínas/metabolismo , Liberación de Histamina , Humanos , Inmunoglobulina E/metabolismo , Técnicas In Vitro , Modelos Moleculares , Conformación Proteica , Pliegue de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/metabolismo
18.
Biosci Biotechnol Biochem ; 65(5): 1082-9, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11440121

RESUMEN

We describe the preparation of Fab fragments of a humanized anti-human high-affinity IgE receptor (Fc epsilonRIalpha) antibody potentially useful for treatment of IgE-mediated allergic diseases. IgE-binding capacities of sixteen combinations of light and heavy chains of four recombinant anti-Fc epsilonRIalpha antibodies, chimeric CRA2, humanized CRA2, chimeric CRA4, and humanized CRA4, were compared. A combination in which both chains were of humanized CRA2 had the highest activity. Stable transfectant clones of four kinds of host cells expressing recombinant antibodies were established. CHO-K1 cells were the most productive. Serum-free media suitable for culture of the stable CHO-transfectant clones were screened. The concentration of the humanized CRA2, which the most productive clone secreted into the chosen serum-free medium, was approximately 100 microg/ml. A procedure for the purification of the antibody, papain-digestion, and purification of Fab fragments was established. The highly purified humanized Fab fragments are suitable for use to examine their in vivo activity and immunogenicity in primates.


Asunto(s)
Anticuerpos/inmunología , Fragmentos Fab de Inmunoglobulinas/aislamiento & purificación , Receptores de IgE/inmunología , Animales , Células CHO , Separación Celular , Cricetinae , Medio de Cultivo Libre de Suero , Ensayo de Inmunoadsorción Enzimática , Citometría de Flujo , Humanos , Inmunoglobulina E/inmunología , Fragmentos Fab de Inmunoglobulinas/inmunología , Papaína/química
20.
Int Arch Allergy Immunol ; 124(4): 454-60, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11340328

RESUMEN

BACKGROUND: The group 1 allergens from mite feces, which belong to the papain-like cysteine protease family, are the most significant in-door allergens. In this study, we analyzed the contribution of the cysteine residues and N-glycosylation in Der f 1, the group 1 allergen from Dermatophagoides farinae, to secretion and maturation by using systems for expression of recombinant Der f 1 (rDer f 1). METHODS: The rDer f 1 and its mutants were expressed in yeast Pichia pastoris and insect SF9 cells. Secretion of their proforms was checked by SDS-PAGE or immunoblotting. Protease activities of the secreted proform of a mutant and the mature form were compared with that of native Der f 1. RESULTS: The proform of a mutant Der f 1, pro-N53Q, whose consensus motif for N-glycosylation was disrupted, was not secreted in insect SF9 cells although secreted in P. pastoris. Indirect evidence was obtained to support the disulfide bond formation between Cys4 and Cys118, which were not conserved in papain. A mutant for Cys35 in the catalytic site of the cysteine protease, pro-C35S/N53Q, was secreted, but the other mutants for cysteines concerning intramolecular disulfide bonds were not secreted in P. pastoris. The prosequence of pro-C35S/N53Q was removed by an in vitro activation process. The mature C35S/N53Q showed low protease activity. CONCLUSION: N-glycosylation is essential for secretion in insect SF9 cells but not in P. pastoris. Disulfide bonds are essential for secretion in P. pastoris. A mutation in the catalytic site, C35S, is not completely critical to removal of the prosequence and protease activity. The findings are useful for future design of recombinant products for application in immunotherapy.


Asunto(s)
Glicoproteínas/genética , Glicoproteínas/metabolismo , Secuencias de Aminoácidos , Animales , Antígenos Dermatofagoides , Cisteína/genética , Cisteína Endopeptidasas/genética , Cisteína Endopeptidasas/metabolismo , Glicosilación , Mutagénesis Sitio-Dirigida , Pichia/genética , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Proteínas Recombinantes , Spodoptera/genética , Transfección
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