RESUMEN
We previously identified an expressed sequence tag clone, Der f 22, showing 41% amino acid identity to published Der f 2, and show that both genes are possible paralogues. The objective of this study was to characterize the genomic, proteomic and immunological functions Der f 22 and Der f 2. The full-length sequence of Der f 2 and Der f 22 coded for mature proteins of 129 and 135 amino acids respectively, both containing 6 cysteine residues. Phylogenetic analysis of known group 2 allergens and their homologues from our expressed sequence tag library showed that Der f 22 is a paralogue of Der f 2. Both Der f 2 and Der f 22 were single gene products with one intron. Both allergens showed specific IgE-binding to over 40% of the atopic patients, with limited of cross-reactivity. Both allergens were detected at the gut region of D. farinae by immunostaining. Der f 22 is an important allergen with significant IgE reactivity among the atopic population, and should be considered in the diagnostic panel and evaluated as future hypoallergen vaccine therapeutic target.
Asunto(s)
Alérgenos/metabolismo , Antígenos Dermatofagoides/metabolismo , Proteínas de Artrópodos/metabolismo , Alérgenos/química , Alérgenos/clasificación , Secuencia de Aminoácidos , Antígenos Dermatofagoides/química , Antígenos Dermatofagoides/clasificación , Proteínas de Artrópodos/química , Proteínas de Artrópodos/clasificación , Secuencia de Bases , Southern Blotting , Ensayo de Inmunoadsorción Enzimática , Inmunoglobulina E/química , Inmunoglobulina E/metabolismo , Datos de Secuencia Molecular , Filogenia , Proteómica/métodosRESUMEN
The allergenic load of house dust mite allergy is largely constituted by a few proteins with a hierarchical pattern of allergenicity. The serodominant specificities are the group 1&2 and the group 23 faecal allergens. The collective IgE binding to the group 1&2 allergens can measure unequivocal HDM sensitisation better than HDM extracts although discrepancies have been found in regions with complex acarofauna suggesting a need to investigate the specificity with allergen components. The group 4, 5, 7&21 allergens that each induce responses in about 40% of subjects are mid-tier allergens accounting for most of the remaining IgE binding. Their titres are proportional to the concomitant responses to Der p1&2. Group 2 allergen variants have different antibody binding. Body proteins only occasionally induce sensitisation although a higher prevalence of binding by atopic dermatitis patients provides a new avenue of research. A broad spectrum of IgE binding has been associated with diverse symptoms but not with the severity of asthma which is associated with low IgG antibody. Some allergens such as the group 14 large lipid binding proteins and the recently described proteins Der f 24-33, need further investigation but with the cognoscence that other denominated allergens have been found to be minor sensitisers by comparative quantitative analyses. Scabies is a confounder for diagnosis with extracts, inducing cross-reactive antibodies with Der p 4&20 as is seafood allergy with cross reactivity to Der p 10 a minor HDM allergen. The HDM genome sequence can now be used to verify allelic and paralogous variations.
Asunto(s)
Alérgenos/inmunología , Antígenos Dermatofagoides/inmunología , Hipersensibilidad/inmunología , Pyroglyphidae/inmunología , Alérgenos/química , Alérgenos/clasificación , Alérgenos/metabolismo , Animales , Antígenos Dermatofagoides/química , Antígenos Dermatofagoides/clasificación , Antígenos Dermatofagoides/metabolismo , Humanos , Hipersensibilidad/diagnóstico , Inmunización , Inmunoglobulina E/inmunologíaRESUMEN
Mite allergens contribute to a significant proportion of human allergic symptoms, including asthma and rhinitis. The development of therapies to treat and prevent these symptoms depends largely on our understanding of the properties of these allergens. Much effort has been devoted to determining the structure and organization of mite allergens, particularly of the house dust mites, toward understanding their activities and how they elicit immunological responses in humans. Here, we review the structural biology of the major allergens from two species of house dust mites, Dermatophagoides farinae and D. pteronyssinus, as well as allergens from a storage mite, Blomia tropicalis. The knowledge gained from the structural biology of these allergens will enable progress in producing novel, more effective treatments for mite allergies based on specific immunotherapy approaches.
Asunto(s)
Alérgenos/química , Antígenos Dermatofagoides/química , Proteínas de Artrópodos/química , Pyroglyphidae/inmunología , Alérgenos/clasificación , Alérgenos/inmunología , Animales , Antígenos Dermatofagoides/clasificación , Antígenos Dermatofagoides/inmunología , Proteínas de Artrópodos/clasificación , Proteínas de Artrópodos/inmunología , Humanos , Hipersensibilidad/inmunología , Hipersensibilidad/terapia , InmunoterapiaRESUMEN
House dust mite allergens (HDMAs) are some of the most common allergens associated with allergic diseases in humans and dogs. The purpose of this study was to determine whether HDMAs could be detected in cat-associated household microenvironments. From 50 cat-only households with 95 cats, dust samples were collected by vacuuming for 2 min m(-2) from three areas where cats slept or rested regularly from September to October 2006. Relative humidity and temperature were measured in each household using a data logger. Each owner completed a questionnaire on potential factors that might influence the prevalence of house dust mites (HDMs). Dust samples were analysed utilizing an ELISA for Der p 1, Der f 1 and HDM group 2 allergens. In 38 of 50 households there was greater than 2 microg g(-1) of dust for at least one HDMA. Using stepwise logistic regression, factors associated with increased HDMA levels included: free-standing houses, number of humans in household, longhaired cats and age of the cat. Factors associated with decreased HDMA concentrations included: forced air heating and central air conditioning, less than 50% carpeting of the home, use of flea control, cats suffering from dermatological disease and the average temperature of the household. Many sleeping/resting areas utilized by cats contain sufficiently high levels of HDMAs to be potential sources of sensitization. This finding should lead to further determination of the role of HDMs in cats suffering from putative allergic conditions such as atopic dermatitis or asthma.
Asunto(s)
Antígenos Dermatofagoides/análisis , Antígenos Dermatofagoides/clasificación , Enfermedades de los Gatos/etiología , Dermatitis Alérgica por Contacto/veterinaria , Animales , Enfermedades de los Gatos/inmunología , Gatos , Dermatitis Alérgica por Contacto/complicaciones , Dermatophagoides farinae , Polvo/análisis , Ambiente , Ensayo de Inmunoadsorción Enzimática , Vivienda , Oportunidad Relativa , Análisis de Regresión , Factores de Riesgo , Encuestas y CuestionariosRESUMEN
BACKGROUND: Few studies have addressed exposure and sensitization to mite allergens in Andean countries. OBJECTIVES: To identify the main mite species in 3 locations at different altitudes in Ecuador and to verify skin test reactivity to various mite species in allergic individuals in Quito, Ecuador. METHODS: Mattress dust samples were collected in Quito (2,800 m above sea level), Cuenca (2,500 m above sea level), and Guayaquil (sea level). Mite species present in the samples were isolated, identified, and counted. Der p 1 and Der f 1 levels were measured using monoclonal antibody-based enzyme immunoassays. Four hundred thirty-five patients in Quito diagnosed as having allergic rhinitis or asthma underwent skin testing with commercial extracts of Dermatophagoides pteronyssinus, Dermatophagoides farinae, Blomia tropicalis, Tyrophagus putrescentiae, and Lepidoglyphus destructor. In addition, Glycyphagus domesticus, Acarus siro, and Aleuroglyphus ovatus were tested in 362, 262, and 279 patients, respectively. RESULTS: Twenty-one mite species were identified. Large populations of mites were detected above 2,500 m of altitude. All the dust samples contained detectable levels of Der p 1 or Der f 1. Positive skin prick test reactions to D. pteronyssinus, D. farinae, B. tropicalis, L. destructor, T. putrescentiae, A. ovatus, A. siro, and G. domesticus were obtained in 60.9%, 56.8%, 17.0%, 19.3%, 10.6%, 15.8%, 8.8%, and 11.0% of the patients, respectively. CONCLUSIONS: Most analyzed mattresses contained several species of mites. Mite allergen levels were high. This study confirms the importance of house dust and storage mite allergens in Ecuador in areas above 2,500 m of altitude, where humidity remains high year round.
Asunto(s)
Acaridae , Antígenos Dermatofagoides/inmunología , Asma/inmunología , Pyroglyphidae , Rinitis/inmunología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Altitud , Antígenos Dermatofagoides/efectos adversos , Antígenos Dermatofagoides/clasificación , Asma/diagnóstico , Asma/epidemiología , Niño , Preescolar , Ecuador/epidemiología , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Rinitis/diagnóstico , Pruebas CutáneasRESUMEN
One hundred consecutive asthmatic paediatric patients were evaluated and skin tested with a battery of skin prick test reagents, including 8 different standardized house dust mite extracts. Asthma severity was graded according to the Global Initiative for Asthma (GINA) document in mild persistent (52 patients), moderate persistent (39) and severe persistent (9). Sixty patients had asthma and allergic rhinitis, 12 asthma and eczema, and 8 asthma, allergic rhinitis and eczema. The patient population was divided into 2 different socioeconomic groups (50 patients per group) based on a standardized, validated questionnaire. A dust sample was collected with an adapted vacuum cleaner from the mattress of each patient and analysed for Der p 1, Der f 1 and Der p 2 allergen content using monoclonal antibodies. Eighty patients were skin test positive to at least one mite species. All positive skin test patients were positive to Dermatophagoides pteronyssinus, 99% to D. farinae, 92% to Euroglyphus maynei, 80% to Lepidoglyphus destructor, 73% to Tyrophagus putrescientae, 72% to Blomia tropicalis; 70% to Acarus siro and 68% to Chortoglyphus arcuatus. All patients with severe persistent asthma had a positive skin test to mites, 85% in the moderate group, and 73% in the mild group (p < 0.01). 95% of patients with asthma and allergic rhinitis had a positive skin test to mites, 92% of patients with asthma and eczema and 100% of patients with asthma, allergic rhinitis and eczema; (p < 0.01). Mean Der p 1, Der f 1 and Der p 2 allergen concentrations were 18.3, 0.6 and 5.6 microg/g of mattress dust, respectively. Mean Der p 1 allergen levels in the middle-low socioeconomic group were significantly higher than in the middle high group (p < 0.01). There is a high rate of allergic sensitisation among pediatric asthmatic patients in Chile. More than one species are implicated, although sensitisation and exposure to D. pteronyssinus predominates. Mite allergic patients are exposed to high mite allergen concentrations, exceeding previously established risk levels for sensitisation and symptoms.
Asunto(s)
Antígenos Dermatofagoides/efectos adversos , Antígenos Dermatofagoides/inmunología , Exposición a Riesgos Ambientales/análisis , Inmunización , Adolescente , Alérgenos/efectos adversos , Alérgenos/inmunología , Antígenos Dermatofagoides/análisis , Antígenos Dermatofagoides/clasificación , Asma/etiología , Asma/terapia , Lechos , Niño , Preescolar , Chile/epidemiología , Dermatitis Atópica/etiología , Dermatitis Atópica/terapia , Exposición a Riesgos Ambientales/efectos adversos , Femenino , Humanos , Masculino , Rinitis Alérgica Perenne/etiología , Rinitis Alérgica Perenne/terapia , Índice de Severidad de la Enfermedad , Pruebas Cutáneas , Clase Social , Encuestas y CuestionariosRESUMEN
BACKGROUND: Blomia tropicalis has been reported to be a clinically important allergen in house dust. High prevalence of sensitization to B. tropicalis has been noted in asthmatic patients in Taiwan; however, the allergenic components and its impact on asthmatic patients remain to be clarified. OBJECTIVE: To analyze the prevalence of IgE against B. tropicalis and each allergenic component in asthmatic patients. METHODS: A series of recombinant allergenic components were used for skin tests. The B. tropicalis specific IgE in the serum were measured using the Pharmacia CAP System and immunoblot analysis. RESULTS: A total of 131 patients were included in this study: 44% of these 131 patients were allergic to B. tropicalis, 43% of the 80 B. tropicalis-sensitive patients were allergic to Blo t 5, and 75% of the 65 Blo t 5-sensitive patients were allergic to Blo t 5 fragment 3 (Blo t 5 70-117). The sera IgE binding activity to B. tropicalis was repeatedly tested after Dermatophagoides pteronyssinus absorption, and results showed that most patients were concurrently sensitized to D. pteronyssinus and B. tropicalis. In addition, in 2 (18%) of 11 patients, the B. tropicalis sensitization was caused by the cross-reactivity of D. pteronyssinus. CONCLUSION: A high prevalence of B. tropicalis sensitization was detected in our asthmatic patients, and most of them were concurrently sensitized to D. pteronyssinus and B. tropicalis. The major allergenic component and its IgE binding fragments in Blo t 5 have been identified. These allergenic components can be used for the allergenic determination in B. tropicalis and for further immunotherapy.
Asunto(s)
Alérgenos/clasificación , Alérgenos/inmunología , Especificidad de Anticuerpos/inmunología , Asma/etiología , Inmunoglobulina E/inmunología , Adolescente , Adulto , Factores de Edad , Alérgenos/efectos adversos , Animales , Antígenos Dermatofagoides/clasificación , Antígenos Dermatofagoides/inmunología , Antígenos de Plantas , Asma/inmunología , Gatos , Niño , Cucarachas/clasificación , Cucarachas/inmunología , Reacciones Cruzadas/inmunología , Culicidae/clasificación , Culicidae/inmunología , Perros , Humanos , Prevalencia , Índice de Severidad de la Enfermedad , Pruebas Cutáneas , Taiwán/epidemiologíaRESUMEN
BACKGROUND: Mite allergens have been involved in airway sensitization and allergic diseases. Immunoassays for the identification and quantifiction of house dust mite (HDM) allergens are useful to improve the knowledge of regional mite fauna and the remediation of mite allergens in allergic diseases. The present study analyzed the association between levels of HDM allergen and results of mite identification or skin prick test (SPT) in two different areas of Bahia, Brazil. METHODS: Forty-two asthmatic subjects from a rural area (group I; n = 21) and a slum (group II; n = 21) were evaluated through SPT with HDM allergens and had dust samples collected at their homes for mite identification and allergen measurements. RESULTS: Positive SPT to Dermatophagoides pteronyssinus, Dermatophagoides farinae and Blomia tropicalis allergens were observed in 42.9, 38.0 and 42.9% subjects from group I and in 47.6, 19.0 and 33.3% subjects from group II, respectively. D. pteronyssinus and B. tropicalis were identified in approximately 76 and 50% of samples from both groups, respectively. D. farinae was identified in 38.0 and 9.5% of samples from groups I and II, respectively (p < 0.005). Der p 1, Der f 1 and Blo t 5 detection were associated with mite identification (p < 0.05). Association between HDM allergen levels over 2 microg/g of dust and positive SPT occurred only with D. pteronyssinus (p < 0.0001). CONCLUSIONS: D. pteronyssinus was the most prevalent mite species in this study followed by B. tropicalis and D. farinae. Immunoassays done to measure mite allergens were associated with mite-species identification. We conclude that these three mite species must be included on panels for the diagnosis of allergic airway diseases in subjects living in such regions.
Asunto(s)
Contaminación del Aire Interior/análisis , Alérgenos/clasificación , Alérgenos/inmunología , Antígenos Dermatofagoides/clasificación , Antígenos Dermatofagoides/inmunología , Asma/inmunología , Microscopía , Pyroglyphidae/clasificación , Pyroglyphidae/inmunología , Pruebas Cutáneas , Adolescente , Adulto , Contaminación del Aire Interior/efectos adversos , Antígenos de Plantas , Proteínas de Artrópodos , Brasil , Niño , Cisteína Endopeptidasas , Femenino , Humanos , Masculino , Salud Rural , Estadística como AsuntoRESUMEN
The examination of house dust mite extracts has indicated that over 30 different proteins can induce IgE antibody in patients allergic to the house dust mite. There are however dominant specificities especially the group 1 and 2 allergens which can account for much of the allergenicity of extracts. Of the 19 denominated allergens, the major IgE binding has been reported for the group 1, 2, 3, 9, 11, 14 and 15 allergens. The high-molecular-weight group 11, 14 and 15 allergens have only recently been described and although high IgE binding has been anticipated from immunoblotting, there is a need for considerable corroboration. Similarly, the study of the group 3 and 9 serine protease allergens has been incomplete. The group 4, 5, 7 and 8 allergens have shown intermediate IgE binding and the group 10 tropomyosins are of interest because of their potential cross-reactivity with allergen from disparate species. Although the progress with the production of recombinant group 1 allergens has been recent, many of the allergens can be produced as high IgE-binding polypeptides. The tertiary structure of the group 2 allergens has been determined from recombinant proteins and they are an excellent model for the investigation of modified allergens. An unexpected property of the group 1, 2 and 3 allergens has been the high degree of polymorphism found by cDNA analysis. It has however been possible to identify sequences to represent the variation in the natural allergens. The group 7 and 14 allergens show secondary modifications which vary in different extracts creating batch variation. While some estimate of the importance of allergens can be obtained from IgE binding, few analyses of T-cell responses have been made and these regulate both the development of, and the protection from sensitization.
Asunto(s)
Alérgenos/inmunología , Polvo , Ácaros/inmunología , Animales , Antígenos Dermatofagoides/clasificación , Antígenos Dermatofagoides/inmunología , Proteínas de Artrópodos , Cisteína Endopeptidasas , Inmunoglobulina E/metabolismo , Proteínas Recombinantes/inmunología , Linfocitos T/inmunologíaRESUMEN
Housedust mites, Dermatophagoides pteronyssinus (D. pteronyssinus) and Dermatophagoides farinae (D. farinae), are the important causative agents of allergic diseases in human and animals. By using 165 dogs suffering from atopic dermatitis (AD), serum levels of immunogloblin E (IgE) antibody against 25 kinds of allergen including housedust mites were determined. Housedust mites were the most frequent allergen against which 90 of the 165 allergic dogs (54.5%) by IMMUNODOT assay. With the further analysis of immunoblotting assay in the 90 dogs sensitized with housedust mites, antigenic proteins of housedust mites recognized by IgE antibodies were with the apparent molecular masses of 15, 76, 90, 98, and 170-kD. Among them, the 15-kD protein that might be identical to Group 2 antigens (Der f2, Der p2) was prominently observed (52/90). This study indicates that about a half of dogs with AD were sensitized to housedust mites, suggesting that Group 2 antigens of housedust mites may be a major allergen in canine AD.
Asunto(s)
Antígenos Dermatofagoides/análisis , Dermatitis Atópica/veterinaria , Enfermedades de los Perros/inmunología , Inmunoglobulina E/sangre , Pyroglyphidae/inmunología , Animales , Antígenos Dermatofagoides/química , Antígenos Dermatofagoides/clasificación , Antígenos Dermatofagoides/inmunología , Dermatitis Atópica/inmunología , Perros , Polvo , Electroforesis en Gel de Poliacrilamida/veterinaria , Ensayo de Inmunoadsorción Enzimática/veterinaria , Femenino , Immunoblotting/veterinaria , Inmunoglobulina E/inmunología , Masculino , Peso MolecularRESUMEN
House dust mites from the family Pyroglyphidae (Dermatophagoides pteronyssinus, D. farinae and Euroglyphus maynei) are recognized as the major source of allergens in house dust and indoor environment. In this review their allergenicity, diagnostics and some biochemical and allergological assays of the allergens produced by these mites are discussed. A brief summary of the mite-derived allergens, their occurrence in some indoor environments and annual dynamics of the mite populations are provided as background.