Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
PLoS One ; 13(10): e0201326, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30321175

RESUMO

In vision science, cascades of Linear+Nonlinear transforms are very successful in modeling a number of perceptual experiences. However, the conventional literature is usually too focused on only describing the forward input-output transform. Instead, in this work we present the mathematics of such cascades beyond the forward transform, namely the Jacobian matrices and the inverse. The fundamental reason for this analytical treatment is that it offers useful analytical insight into the psychophysics, the physiology, and the function of the visual system. For instance, we show how the trends of the sensitivity (volume of the discrimination regions) and the adaptation of the receptive fields can be identified in the expression of the Jacobian w.r.t. the stimulus. This matrix also tells us which regions of the stimulus space are encoded more efficiently in multi-information terms. The Jacobian w.r.t. the parameters shows which aspects of the model have bigger impact in the response, and hence their relative relevance. The analytic inverse implies conditions for the response and model parameters to ensure appropriate decoding. From the experimental and applied perspective, (a) the Jacobian w.r.t. the stimulus is necessary in new experimental methods based on the synthesis of visual stimuli with interesting geometrical properties, (b) the Jacobian matrices w.r.t. the parameters are convenient to learn the model from classical experiments or alternative goal optimization, and (c) the inverse is a promising model-based alternative to blind machine-learning methods for neural decoding that do not include meaningful biological information. The theory is checked by building and testing a vision model that actually follows a modular Linear+Nonlinear program. Our illustrative derivable and invertible model consists of a cascade of modules that account for brightness, contrast, energy masking, and wavelet masking. To stress the generality of this modular setting we show examples where some of the canonical Divisive Normalization modules are substituted by equivalent modules such as the Wilson-Cowan interaction model (at the V1 cortex) or a tone-mapping model (at the retina).


Assuntos
Psicofísica , Córtex Visual/fisiologia , Algoritmos , Humanos , Modelos Lineares , Aprendizado de Máquina , Modelos Neurológicos , Neurociências/métodos , Dinâmica não Linear , Visão Ocular
2.
Allergy ; 71(2): 220-9, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26485347

RESUMO

BACKGROUND: Understanding patterns of IgE sensitization in Dermatophagoides-allergic patients living in various geographical areas is necessary to design a product suitable for worldwide allergen immunotherapy (AIT). METHODS: Using a HIFI Allergy customized microarray assay, IgEs specific for 12 purified allergens from Dermatophagoides pteronyssinus or D. farinae were assessed in sera from 1302 house dust mite (HDM)-allergic patients living in various areas. Comprehensive mass spectrometric (MS) analyses were conducted to characterize HDM extracts, as well as purified bodies and feces. RESULTS: Patterns of IgE reactivity to HDM allergens are comparable in all cohorts of patients analyzed, encompassing adults and 5- to 17-year-old children, as well as American, Canadian, European, and Japanese patients. Overall, >70% and >80% of HDM-allergic patients are sensitized to group 1 and group 2 allergens, respectively, from D. pteronyssinus and/or D. farinae species. Furthermore, 20-47% of patients also have IgEs to allergens from groups 4, 5, 7, 13, 15, 21, and 23. All patients have IgEs to allergens present in mite bodies and feces. MS-based analyses confirmed the presence of mite allergens recorded by IUIS in D. pteronyssinus and D. farinae extracts, with groups 2, 8, 10, 11, 14, and 20 prominent in bodies and groups 1, 6, 18, and 23 well represented in feces. CONCLUSIONS: Mite-specific AIT should rely upon a mixture of D. pteronyssinus and D. farinae extracts, manufactured from both feces and bodies. Such a combination is appropriate to treat children and adult Dermatophagoides-allergic patients from Asia, Europe, and North America.


Assuntos
Alérgenos/imunologia , Antígenos de Dermatophagoides/imunologia , Hipersensibilidade/imunologia , Imunoglobulina E/imunologia , Pyroglyphidae/imunologia , Adolescente , Adulto , Alérgenos/isolamento & purificação , Animais , Especificidade de Anticorpos , Antígenos de Dermatophagoides/isolamento & purificação , Criança , Pré-Escolar , Dessensibilização Imunológica , Europa (Continente) , Feminino , Humanos , Hipersensibilidade/diagnóstico , Hipersensibilidade/terapia , Imunização , Imunoglobulina E/sangue , Masculino , Adulto Jovem
3.
Allergy ; 70(7): 795-804, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25846209

RESUMO

BACKGROUND: Sublingual immunotherapy (SLIT) applied to type I respiratory allergies is commonly performed with natural allergen extracts. Herein, we developed a sublingual tablet made of pharmaceutical-grade recombinant Bet v 1.0101 (rBet v 1) and investigated its clinical safety and efficacy in birch pollen (BP)-allergic patients. METHODS: Following expression in Escherichia coli and purification, rBet v 1 was characterized using chromatography, capillary electrophoresis, circular dichroism, mass spectrometry and crystallography. Safety and efficacy of rBet v 1 formulated as a sublingual tablet were assessed in a multicentre, double-blind, placebo-controlled study conducted in 483 patients with BP-induced rhinoconjunctivitis. RESULTS: In-depth characterization confirmed the intact product structure and high purity of GMP-grade rBet v 1. The crystal structure resolved at 1.2 Å documented the natural conformation of the molecule. Native or oxidized forms of rBet v 1 did not induce the production of any proinflammatory cytokine by blood dendritic cells or mononuclear cells. Bet v 1 tablets were well tolerated by patients, consistent with the known safety profile of SLIT. The average adjusted symptom scores were significantly decreased relative to placebo in patients receiving once daily for 5 months rBet v 1 tablets, with a mean difference of 17.0-17.7% relative to the group treated with placebo (P < 0.025), without any influence of the dose in the range (12.5-50 µg) tested. CONCLUSION: Recombinant Bet v 1 has been produced as a well-characterized pharmaceutical-grade biological drug. Sublingual administration of rBet v 1 tablets is safe and efficacious in patients with BP allergic rhinoconjunctivitis.


Assuntos
Alérgenos/imunologia , Antígenos de Plantas/imunologia , Pólen/imunologia , Proteínas Recombinantes , Rinite Alérgica Sazonal/imunologia , Rinite Alérgica Sazonal/terapia , Imunoterapia Sublingual , Adolescente , Adulto , Alérgenos/química , Alérgenos/genética , Alérgenos/isolamento & purificação , Antígenos de Plantas/química , Antígenos de Plantas/genética , Antígenos de Plantas/isolamento & purificação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Moleculares , Conformação Proteica , Testes de Função Respiratória , Rinite Alérgica Sazonal/diagnóstico , Fatores de Risco , Imunoterapia Sublingual/efeitos adversos , Adulto Jovem
4.
Eur Ann Allergy Clin Immunol ; 45 Suppl 2: 33-7, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-24129086

RESUMO

Relevant allergens are major contributors to the safety and efficacy of allergenic extracts used in allergen immunotherapy (AIT). As such, they should be accurately quantified, as recommended by the 2008 European guidelines on allergen products. Until now, the quantification of relevant allergens was mainly performed by using immunoassays (e.g. ELISA) that relying upon specific antibodies. Although antibody-based quantification is commonly used to assess the concentration of relevant allergens in allergenic extracts, results must be taken with caution in the light of the inherent limitations of such techniques. In the present study, we discuss how those limitations can be overcome by using comprehensive mass spectrometry-based techniques.


Assuntos
Alérgenos/análise , Dessensibilização Imunológica , Ensaio de Imunoadsorção Enzimática , Espectrometria de Massas
5.
Clin Exp Allergy ; 42(10): 1510-8, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22994348

RESUMO

BACKGROUND: The impact of sublingual immunotherapy (SLIT) on IgE neosensitization remains to be evaluated in large cohorts of patients. OBJECTIVES: The aim of this study was to assess the dynamics of antibody responses induced in patients with allergic rhinitis during a 12-month treatment with sublingual tablets of house dust mites (HDM) allergen extracts. METHODS: Antibody responses were assessed in relationship with neosensitization and clinical benefit in sera from 509 European house dust mite-allergic patients before and after 1 year of daily sublingual immunotherapy, using tablets containing Dermatophagoides pteronyssinus plus D farinae extracts or placebo (ClinicalTrials.gov NCT00674700). Patients were followed for one additional year after treatment cessation. IgE and IgG4 antibodies specific for mite extracts or purified group 1, 2 and 10 allergens were assessed using Immulite, Immunocap and ISAC assays. RESULTS: After 1 year of SLIT, mite-specific IgE and IgG4 titres increased by 1.5-fold and fourfold, respectively, in the active, but not in the placebo group. A strong IgG4 induction occurred in a subgroup (i.e. 10-15%) of "immunoreactive" patients, without any correlation with improvement in the average adjusted symptom score. Pre-existing IgE levels to purified mite allergens were not impacted during immunotherapy, and no de novo IgE responses to group 1, 2, 10 allergens were induced in patients who were unsensitized prior to immunotherapy. Similarly, no IgE neosensitization to wheat germ or yeast components used in the mite culture medium was observed. CONCLUSIONS AND CLINICAL RELEVANCE: We document in a cohort of 509 patients followed over a 2-year period that SLIT does not induce any IgE neosensitization to allergens contained in the vaccine, such as groups 1, 2 as well as the food-related group 10 allergen. This observation further corroborates the safer safety profile of SLIT over SCIT.


Assuntos
Dermatophagoides farinae/imunologia , Dermatophagoides pteronyssinus/imunologia , Dessensibilização Imunológica/métodos , Imunoglobulina E/sangue , Imunoglobulina G/sangue , Administração Sublingual , Adolescente , Adulto , Animais , Antígenos de Dermatophagoides/administração & dosagem , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pyroglyphidae/imunologia , Rinite Alérgica Perene/terapia , Comprimidos/administração & dosagem , Resultado do Tratamento , Adulto Jovem
6.
Vaccine ; 30(38): 5666-74, 2012 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-22776213

RESUMO

AIM: Intravenous immunoglobulin (IVIG) displays anti-inflammatory activities in many diseases. Subcutaneous administration of anti-IgE in humans provides benefit in severe persistent allergic asthma. Given the well established efficacy of sublingual allergen immunotherapy in respiratory type I allergies, we investigated the therapeutic potential of sublingual immunoglobulin (SLIG), most particularly anti-IgE SLIG, in a murine model of allergen-driven airway inflammation. METHODS: BALB/c mice sensitized with ovalbumin (OVA) were treated sublingually with rat monoclonal IgG1 or IgG2a, either directed to mouse IgE or with no reported specificity. Airway hyperresponsiveness (AHR) was assessed by whole body plethysmography, and eosinophil infiltrates were characterized in bronchial alveolar lavages (BAL). OVA-specific antibody and T cell responses were analyzed in sera and saliva or lung and draining lymph nodes, by ELISA or CBA measurement of cytokine production, respectively. RESULTS: AHR and BAL eosinophil infiltrates were substantially decreased in mice treated sublingually with particulate OVA (positive control), as well as in animals receiving various rat IgG1, irrespective of their specificity for murine IgE. In contrast, no improvement was observed in mice treated with PBS (negative control) or various rat IgG2a. SLIG anti-inflammatory activity is not related to a downregulation of Th2, Th17 or an induction of Foxp3(+) CD4(+) regulatory T cell responses. Mass spectrometry analysis of glycan moieties, such as sialic acid, suggests that the differential efficacy of rat IgG1 and IgG2a is not related to their capacity to interact with lectins borne by oral immune cells. CONCLUSIONS: In a murine model of allergen-driven airway inflammation, SLIG exhibits an anti-inflammatory activity irrespective of the immunoglobulin specificity, and in the absence of allergen. As a noninvasive approach, SLIG deserves to be further studied as a treatment for other inflammatory diseases beyond allergic asthma.


Assuntos
Anti-Inflamatórios/administração & dosagem , Anticorpos Anti-Idiotípicos/administração & dosagem , Hipersensibilidade/terapia , Imunoglobulina G/administração & dosagem , Imunoterapia/métodos , Doenças Respiratórias/terapia , Administração Sublingual , Animais , Anticorpos Monoclonais/administração & dosagem , Líquido da Lavagem Broncoalveolar/citologia , Eosinófilos/imunologia , Feminino , Humanos , Pulmão/patologia , Camundongos , Camundongos Endogâmicos BALB C , Ovalbumina/imunologia , Pletismografia Total , Resultado do Tratamento
7.
Clin Exp Allergy ; 40(3): 505-19, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19895591

RESUMO

BACKGROUND: Differences between major allergens from distinct grass species remain to be investigated, both in terms of structure and antigenicity. METHODS: Group 1 and 5 allergens purified from five common Pooideae species were analysed by mass spectrometry (MS). Major histocompatibility complex (MHC) class II-restricted T cell epitopes were identified using predictive algorithms and human leucocyte antigen (HLA)-binding assays. CD4+ T cell reactivity and IgE binding were assessed based on the induction of CD154 expression in peripheral blood mononuclear cells and using competitive ELISA assays, respectively. RESULTS: MS analysis of group 5 pollen allergens reveals considerable intra- and inter-species variability in amino acid sequence, with 30-50 predominant isoforms found for each species. Differences in the amino acid sequence as well as N- and O-glycosylation contribute to the variability of group 1 allergens, yielding 5-10 main isoforms, depending on the species. Out of 14 MHC class II-restricted T cell epitopes identified within group 1, only one is conserved among the five grass species. Significant differences in binding affinities for HLA-DR molecules result in variable CD4+ T cell recognition of group 1 and 5 allergens purified from the various species. Up to 38% and 85% of patients exhibit seric IgE responses to species-restricted (or semi-restricted) epitopes associated with group 1 or 5 allergens, respectively. CONCLUSION: Major pollen allergens from distinct grass species bear both shared and species-restricted T and B cell immune epitopes. When compared with single extracts, a five grass pollen extract is thus more suitable for specific immunotherapy, as it contains a broader repertoire of the IgE epitopes to which patients are sensitized.


Assuntos
Alérgenos/química , Alérgenos/classificação , Dessensibilização Imunológica , Poaceae/química , Poaceae/classificação , Pólen/química , Alérgenos/imunologia , Alérgenos/isolamento & purificação , Sequência de Aminoácidos , Animais , Reações Antígeno-Anticorpo , Epitopos/química , Epitopos/imunologia , Humanos , Imunoglobulina E/imunologia , Leucócitos/imunologia , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Mapeamento de Peptídeos , Conformação Proteica , Especificidade da Espécie , Linfócitos T/imunologia
8.
Clin Exp Allergy ; 39(5): 760-70, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19226276

RESUMO

BACKGROUND: As a complex molecule requiring post-translational processing, it has been difficult to produce the Der p 1 major allergen from the Dermatophagoides pteronyssinus house dust mite in a recombinant form. OBJECTIVE: Here, we tested whether transgenic tobacco plants are suitable to express Der p 1, either as a wild-type molecule or as variants lacking N-glycosylation sites (Gly(-)) and/or cysteine protease activity (Enz(-)). Methods Using Agrobacterium tumefaciens-based transformation, pro Der p 1 molecules bearing mutations within either the N-glycosylation sites (N34Q, N150Q) and/or the cysteine protease-active site (C132V) were expressed in tobacco plants. After purification by ion exchange chromatography, allergens were characterized using immunoblotting, circular dichroism (CD), as well as basophil and T lymphocyte stimulation assays. RESULTS: Four forms of recombinant Der p 1 (i.e. wild-type Gly(+)/Enz(+), as well as Gly(-)/Enz(+), Gly(+)/Enz(-) or Gly(-)/Enz(-) variants) were successfully expressed in tobacco leaves as pro Der p 1 molecules. Spontaneous cleavage of the pro-peptide was observed in tobacco leaf extracts for all forms of recombinant Der p 1 (r Der p 1). CD confirmed that all r Der p 1 molecules, with the exception of the Gly(-)/Enz(-) variant, exhibited secondary structures comparable to the natural protein. A cysteine protease activity was associated only with the Gly(+)/Enz(+) form. All these molecules exhibit a profile similar to natural Der p 1 with respect to IgE immunoreactivity, basophil activation and T cell recognition. CONCLUSION: A tobacco plant expression system allows the production of various forms of mature Der p 1, which could be used for diagnostic or immunotherapeutic purposes.


Assuntos
Antígenos de Dermatophagoides/biossíntese , Clonagem Molecular , Nicotiana/genética , Antígenos de Dermatophagoides/genética , Antígenos de Dermatophagoides/imunologia , Proteínas de Artrópodes , Basófilos/imunologia , Basófilos/metabolismo , Linhagem Celular , Cisteína Endopeptidases , Humanos , Diester Fosfórico Hidrolases/imunologia , Diester Fosfórico Hidrolases/metabolismo , Folhas de Planta/genética , Plantas Geneticamente Modificadas , Pirofosfatases/imunologia , Pirofosfatases/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Linfócitos T/imunologia , Linfócitos T/metabolismo
9.
Allergy ; 61(2): 151-65, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16409190

RESUMO

Sublingual immunotherapy has been shown in some clinical studies to modulate allergen-specific antibody responses [with a decrease in the immunoglobulin E/immunoglobulin G4 (IgE/IgG4) ratio] and to reduce the recruitment and activation of proinflammatory cells in target mucosa. Whereas a central paradigm for successful immunotherapy has been to reorient the pattern of allergen-specific T-cell responses in atopic patients from a T helper (Th)2 to Th1 profile, there is currently a growing interest in eliciting regulatory T cells, capable of downregulating both Th1 and Th2 responses through the production of interleukin (IL)-10 and/or transforming growth factor (TGF)-beta. We discuss herein immune mechanisms involved during allergen-specific sublingual immunotherapy (SLIT), in comparison with subcutaneous immunotherapy. During SLIT, the allergen is captured within the oral mucosa by Langerhans-like dendritic cells expressing high-affinity IgE receptors, producing IL-10 and TGF-beta, and upregulating indoleamine dioxygenase (IDO), suggesting that such cells are prone to induce tolerance. The oral mucosa contains limited number of proinflammatory cells, such as mast cells, thereby explaining the well-established safety profile of SLIT. In this context, second-generation vaccines based on recombinant allergens in a native conformation formulated with adjuvants are designed to target Langerhans-like cells in the sublingual mucosa, with the aim to induce allergen-specific regulatory T cells. Importantly, such recombinant vaccines should facilitate the identification of biological markers of SLIT efficacy in humans.


Assuntos
Administração Sublingual , Alérgenos/administração & dosagem , Alérgenos/imunologia , Dessensibilização Imunológica/métodos , Hipersensibilidade/prevenção & controle , Antialérgicos/administração & dosagem , Humanos , Imunoterapia Ativa , Injeções Subcutâneas , Mucosa Bucal/imunologia , Linfócitos T/imunologia
10.
J Allergy Clin Immunol ; 106(4): 669-76, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11031337

RESUMO

BACKGROUND: Antiallergen mAbs that do not recognize clinically important isoforms have been described, raising the question of the selection of mAbs for quantifying major allergens in order to standardize allergenic extracts. This question is even more critical if mAbs can discriminate between different forms of allergen molecules with the same amino acid sequence. OBJECTIVE: We sought to demonstrate that an anti-Fel d 1 mAb was able to discriminate between two forms of the major cat allergen independently of its amino acid sequence and to determine the relative importance and stability of both forms in various cat extracts. METHODS: Anti-Fel d 1 mAbs were raised in mice and characterized. By using two of these mAbs, a two-site ELISA was developed to quantify Fel d 1 in mass units. RESULTS: One of the anti-Fel d 1 mAbs developed was shown to specifically recognize a particular form of Fel d 1. A two-site ELISA with this mAb to capture Fel d 1 was able to quantify the allergen specifically in this form. It was then shown that (1) the quantitative importance of this form of Fel d 1 could vary from one cat extract to another, (2) Fel d 1 was converted into this form under certain conditions, and (3) both converted and unconverted forms of Fel d 1 may bear IgE epitopes that are specific. CONCLUSION: Although the present study emphasizes the issue of selecting mAbs that are not too specific to standardize allergenic extracts, it also demonstrates that very specific mAbs can be of interest, especially to verify the stability of allergens in extracts, since this stability might have clinical implications.


Assuntos
Glicoproteínas/imunologia , Animais , Anticorpos Monoclonais/imunologia , Gatos , Cromatografia em Gel , Ensaio de Imunoadsorção Enzimática , Epitopos/análise , Epitopos/sangue , Hipersensibilidade Respiratória/sangue
11.
Allergy ; 53(7): 662-72, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9700035

RESUMO

For evaluation of the efficacy and the safety of specific sublingual immunotherapy with high allergen dose, 66 children with seasonal asthma, rhinitis, and conjunctivitis due to sensitization to olive pollen were enrolled in a double-blind, randomized, placebo-controlled study between October 1994 and October 1996 in Greece. Thirty-four patients were randomly allocated to the active group, and 32 received placebo. Immunotherapy consisted of olive-allergen extracts (Stallergènes SA) administered sublingually pre- and coseasonally from January to July for 2 consecutive years. Serial concentrations from 1 to 300 IR. were used up to the maintenance dose of 20 drops of 300 IR daily. The cumulative dose for each patient was 300 times higher than in parenteral immunotherapy, and the cumulative dose of the major allergen Ole e 1 was 8.1 mg/2 years. The patients were assessed by clinical parameters (symptom and medication scores from patients' daily diaries) and immunologic measurements (specific IgE, IgG4, eosinophil cationic protein [ECP]) were performed. The actively treated patients had a significantly lower score for dyspnea (P<0.04 during the first season; P<0.03 during the second season). At the pollinic peak during the second year, a lower score of conjunctivitis was recorded (P<0.05) in the actively treated patients. The analysis of intragroup evolution showed that the total score of rhinitis increased significantly during the pollinic peak in the group under placebo, whereas there was no symptomatic peak for the same period in the group under active treatment. However, the difference between the groups was not significant. The medication score did not differ significantly between the groups. Oral steroids were the only variables with a P value near the significance level (P=0.06) in favor of the actively treated group. A significant decrease in skin reactivity was recorded in the active group after 2 years of treatment. No significant variation in specific IgE and IgG4 was detected. A significantly lower level of serum ECP was observed at the pollinic peak in the actively treated patients during the first pollen season (P=0.01), but this was not confirmed the second year when the ECP levels doubled in both groups without correlation to the clinical findings. Tolerance was excellent with only a few minor side-effects reported. In conclusion, high-dose specific sublingual immunotherapy appears to be safe and effective in improving mild seasonal asthma and conjunctivitis linked to olive-pollen sensitization.


Assuntos
Asma/terapia , Conjuntivite Alérgica/terapia , Fitoterapia , Pólen/uso terapêutico , Rinite Alérgica Sazonal/terapia , Administração Sublingual , Adolescente , Asma/imunologia , Criança , Dessensibilização Imunológica , Método Duplo-Cego , Dispneia/tratamento farmacológico , Feminino , Frutas/imunologia , Humanos , Imunoglobulina E/sangue , Imunoglobulina G/sangue , Estudos Longitudinais , Masculino , Extratos Vegetais/uso terapêutico , Rinite Alérgica Sazonal/imunologia , Testes Cutâneos , Esteroides/uso terapêutico
12.
Clin Exp Allergy ; 26(11): 1308-15, 1996 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8955580

RESUMO

BACKGROUND: Blocking antibodies are defined as antibodies that compete with IgE for binding to allergens due to their specificity for those allergens. Thus, they may inhibit allergen-induced basophil and mast cell IgE-dependent mediator release both in vivo and in vitro. OBJECTIVE: The present study was designed to evaluate the ability of antibodies isolated from human plasma samples on a Dactylis glomerata (Cocksfoot) pollen affinity-column to inhibit the Dactylis pollen-induced histamine release from human basophils (BHR) in vitro. METHODS: Antibodies from Ig pools containing either high or low IgG4 anti-Dactylis pollen were purified on a Dactylis pollen affinity-column and then separated on an antihuman IgE column. Obtained Ig fractions were incubated for 30 min with Dactylis pollen allergens prior to incubation with basophils from Dactylis pollen-allergic donors. Cell supernatants were assessed for histamine content and the inhibition of BHR was calculated. RESULTS: Unlike control non-isolated Igs, the antibodies isolated on the Dactylis pollen column were able to inhibit efficiently and in a dose-dependent manner Dactylis pollen-induced BHR. The inhibitory activity was increased in isolated antibody samples that had high IgG4 levels. Antibodies isolated on the Dactylis pollen column, however, consisted not only of true allergen-specific (potentially blocking) antibodies but also of autoanti-IgE binding to allergen-specific IgE and mistaken for allergen-specific antibodies thus opening to question the involvement of the true allergen-specific antibodies in the BHR-inhibitory activity. Unlike the true allergen-specific antibodies, the autoanti-IgE were retained on and eluted from the anti-IgE column. Results showed that both the autoanti-IgE-depleted and the autoanti-IgE-containing fractions accounted for the inhibition observed with the related non-depleted sample that had been isolated on the Dactylis pollen column. CONCLUSION: For the first time, the true blocking activity of allergen-specific antibodies is demonstrated, that is, in the absence of the autoanti-IgE which can also inhibit BHR.


Assuntos
Isotipos de Imunoglobulinas/sangue , Pólen/imunologia , Alérgenos/imunologia , Anticorpos Anti-Idiotípicos/sangue , Anticorpos Bloqueadores/imunologia , Especificidade de Anticorpos , Autoanticorpos/imunologia , Basófilos/metabolismo , Cromatografia de Afinidade , Ensaio de Imunoadsorção Enzimática , Liberação de Histamina/fisiologia , Humanos , Imunoglobulina E/imunologia
13.
Allergy ; 51(7): 473-81, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8863924

RESUMO

Since it has been shown that autoanti-IgE may be mistaken for antiallergen antibodies, thus appearing as pseudo-allergen-specific antibodies, it is crucial to separate true-from pseudo-allergen-specific antibodies and to determine to what extent autoanti-IgE appeared as pseudo-allergen-specific antibodies. For this purpose, human Ig pools were affinity-purified successively on a grass-pollen column and then on an antihuman-IgE column. IgG1-4, IgA, and IgM antibodies that were eluted from the grass-pollen column separated into pseudo- (approximately 30-40%) and true-allergen-specific antibodies that were coretained and not coretained, respectively, with the IgE on the anti-IgE column. Levels of autoanti-IgE were determined in individual plasma samples by surface plasmon resonance and statistically compared to the concentrations of allergen-specific antibodies obtained previously in the same plasma samples. A positive correlation between IgM autoanti-IgE levels and grass-pollen- "specific" IgM concentrations (P < 0.0002), and negative correlations between IgA autoanti-IgE and both IgE anti-grass pollen and IgG2 autoanti-IgE levels (P < 0.03, in both cases) were observed for the first time. This supports the contentions that: (1) autoanti-IgE antibodies appeared as pseudo-grass-pollen-specific antibodies, (2) they hid IgE antibodies when the latter were measured, and (3) they compete with one another in binding IgE. Lastly, a model of large Ig complexes is discussed.


Assuntos
Isotipos de Imunoglobulinas/sangue , Pólen/imunologia , Anticorpos Anti-Idiotípicos/análise , Anticorpos Anti-Idiotípicos/imunologia , Especificidade de Anticorpos , Autoanticorpos/análise , Autoanticorpos/sangue , Sítios de Ligação de Anticorpos , Ligação Competitiva , Cromatografia de Afinidade , Cromatografia em Gel , Humanos , Imunoglobulina E/imunologia
14.
J Immunol Methods ; 167(1-2): 219-25, 1994 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-8308278

RESUMO

This study describes the use of electrophoretically purified antigens blotted onto nitrocellulose, as solid phase antigens for enzyme-linked immunosorbent assays. This procedure is called DMISA, for dissociated membrane immunosorbent assay. The method is illustrated using immunoblotted antigens of Dactylis glomerata grass pollen extract. The band of interest was located on a print of nitrocellulose by light staining (India ink), then the corresponding strip of nitrocellulose was cut out. Immediately after its solubilization in ethyleneglycol monomethyl ether, the antigen coated nitrocellulose was precipitated by the addition of buffer. In this way the bulk of the antigen remained bound to the membrane. The resulting suspension was carefully washed, and used as a solid phase antigen in an enzyme-linked immunosorbent assay. Two different electrophoretic methods were used to separate the Dactylis glomerata antigens. We compared the results obtained with classical immunoblot and with DMISA, for IgG4 and IgE quantification using sera from patients allergic to D. glomerata and purified blotted antigens present at the nanogram level.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Immunoblotting/métodos , Alérgenos/análise , Alérgenos/imunologia , Colódio , Membranas Artificiais , Proteínas de Plantas/análise , Proteínas de Plantas/imunologia , Pólen/imunologia
15.
Int Arch Allergy Immunol ; 102(3): 279-87, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8219781

RESUMO

Previously, the specificity of human immune responses to Dactylis pollen was analyzed in 26 plasma samples with high levels of grass-pollen-specific IgG4 ('IgG4+ plasma', largely from grass-pollen-allergic patients), as compared to 25 plasma samples with low grass-pollen-specific IgG4 ('normal plasma', from nonatopic individuals). In the present study, a quantification of the Dactylis-pollen-specific IgE, IgM, IgA class and IgG subclass antibodies in these plasma samples is proposed. Isotypic distribution in IgG4+ plasma was 68% IgG [IgG2 (38%) > IgG4 (30%) > IgG1 (19%) > IgG3 (13%)], 27% IgM, 4% IgA and 0.05% IgE. In normal plasma it was 73% IgM, 20% IgG [IgG3 (38%) > IgG2 (33%) > IgG1 (29%) > IgG4 (0%)], 6% IgA and 0.006% IgE. In IgG4+ plasma, specific IgE, IgG1, IgG2 and IgG4 concentrations were positively correlated between each other. Finally, the present study clearly confirmed the possible role of the CH gene regulation in allergic diseases.


Assuntos
Hipersensibilidade/imunologia , Isotipos de Imunoglobulinas/imunologia , Poaceae/imunologia , Pólen/imunologia , Regulação da Expressão Gênica , Genes de Imunoglobulinas , Humanos , Imunoglobulina A/imunologia , Imunoglobulina E/imunologia , Imunoglobulina G/imunologia , Isotipos de Imunoglobulinas/genética , Imunoglobulina M/imunologia , Proteínas de Plantas/imunologia
16.
Int Arch Allergy Immunol ; 100(1): 68-78, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8428167

RESUMO

The specificity and isotypic profile of humoral immune responses to Dactylis glomerata (Cocksfoot) pollen was studied by isoelectric focusing (IEF)-immunoprint analysis using 26 human plasma samples with high levels of Dactylis pollen-specific IgG4 (IgG4+ plasma) and 25 human plasma samples with low levels of specific IgG4 (normal plasma). Over 60 individual protein components in an aqueous pollen extract were separated by IEF and immunoprinted onto nitrocellose (NC). Following plasma incubation, bound IgE, IgG1-4, IgA1, IgA2 and IgM antibodies were detected on separate immunoprints with isotype-specific antibodies. Binding patterns of IgG4 and the majority of IgG1 and IgA2 antibodies in the IgG4+ plasma group very closely paralleled the binding patterns produced by the IgE antibodies from the same plasma and are described as the 'allergen repertoire'. In contrast, IgE, IgG4, IgG1 and IgA2 antibody reactivities to the 'allergen repertoire' were insignificant in the normal plasma group. These results suggest a qualitative, as well as a quantitative relationship between the immune responses which involve these 4 isotypes. Characteristic IgG2 and IgM antibody binding patterns, predominantly to non-allergenic antigens, were shared by the plasma from both groups, while IgG3 and IgA1 antibody binding patterns were highly variable from one plasma to another in both groups. One possible origin of the allergic diseases at the immunoglobulin heavy chain gene level is discussed.


Assuntos
Isotipos de Imunoglobulinas/sangue , Pólen/imunologia , Formação de Anticorpos , Especificidade de Anticorpos , Ensaio de Imunoadsorção Enzimática , Humanos , Immunoblotting , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Focalização Isoelétrica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...