Analysis of cross-reactivity between group 1 allergens from mites

Mite allergen exposure can lead to sensitization in genetically predisposed individuals, and the development of asthma in previously sensitized individuals. The major allergens of mites belong to Dermatophagoides spp. and Blomia tropicalis (Bt). Various allergens of Bt have been cloned and sequenced. Some of them show homology sequence with purified allergens from Dermatophagoides pteronissynus (Dp). Recently, the allergen group 1 from Bt, Blo t 1, was cloned and sequenced at our laboratory. Recombinant Blo t 1 showed 35 % of identity and 50% of similarity with group 1 allergens as Der p 1 (from Dp), Der f 1 (from D. farinae) and Eur m 1 (from Euroglyphus maynei) at amino acid level. This would suggest that cross-reactivity between allergens of different mite species could exist. Here, we analyzed the crossreactivity between group 1 allergens from mites using recombinant proteins and monoclonal antibodies against them. ELISA inhibition assay showed that crossreactivity between homologous allergens from Dermatophagoides spp. is high, but it is low to moderate between mites from different species. IgE-reactivity analysis using serum samples from allergic individuals revealed a strong reactivity of rBlo t 1 for serum samples from subjects with highly positive reaction to Bt extract in skin test, but lack of reactivity of this protein with serum samples from individuals with highly positive reaction to house dust mite extract in the skin test. These results suggest that it is important to include Bt allergens in routine skin test in order to improve the diagnostic accuracy and precision of allergies.

Allergy to house dust mites and asthma

House dust mites have been shown to be important sources of indoor allergens associated with asthma and other allergic conditions. Asthma is a chronic respiratory disease that affects millions of people worldwide, and numerous scientific studies have shown that the prevalence of asthma is increasing. The most common dust mite species around the world include Dermatophagoides pteronyssinus (Dp), Dermatophagoides farinae (Df), Euroglyphus maynei (Em) and Blomia tropicalis (Bt). Over the past three decades, many important allergens from these species have been identified and characterized at the molecular level. The biological function of several house dust mite allergens has been elucidated, with many of them showing enzymatic activity. However, Bt allergens remain the least studied, even though this mite is very common in tropical and subtropical regions of the world, including Puerto Rico. Therefore, it is very important to include Bt in diagnostic and therapeutic strategies for house dust mite induced allergy and asthma, particularly in areas where Bt exposure and sensitization is high. Recombinant DNA technology, as well as other molecular biology and immunological techniques, have played a fundamental role in advances towards a better understanding of the biology of house dust mites and their role in allergic diseases. This kind of study also contributes to the understanding of the complex immunologic mechanisms involved in allergic reactions. The development of effective diagnostic and therapeutic approaches depends on the continuity of research of house dust mite allergens. The objectives of this review are to describe the most important aspects of house dust mite allergy and to acquaint the scientific community with the latest findings pertaining to house dust mite allergens, particularly those derived from Bt.

IgE reactivity from serum of Blomia tropicalis allergic patients to the recombinant protein Blo t 1

OBJECTIVE: To determine the IgE reactivity against recombinant protein Blo t 1 from the dust mite Blomia tropicalis (Bt) using serum from patients with positive skin test to this mite and to investigate the cross-reactivity between Bt and Dermatophagoides pteronyssinus. BACKGROUND: Dust mites have an important role as inducers of allergic asthma and rhinitis. Particularly, Bt is an important mite specie in the tropic and subtropical regions of the world. Therefore, recombinant allergens of this organism could be an important feature for development of effective diagnostic and therapeutic measures. MATERIALS AND METHODS: Purified recombinant Blot t 1 was produced in Escherichia coli and tested against sera from 54 allergic individuals by the dot blot technique. RESULTS: IgE response to Blot 1 was 72% for sera from patients with positive skin test to Bt. Cross-reactivity with Dermatophagoides pteronyssinus was not detected. Statistical analyses of the dot blot test results show 71.74% of sensitivity and 100% of specificity. CONCLUSION: By using a panel of allergic sera and an in vitro assay, the allergen rBlo t 1 exhibits no IgE cross-reactivity with Dermathophagoides pteronyssinus allergens. This finding suggests that specific clinical reagents are necessary for precise diagnosis and treatment of sensitization to Bt.

Monoclonal antibodies against whole body extract of the dust mite Blomia tropicalis

OBJECTIVE: To produce and characterize monoclonal antibodies (mAbs) against whole body extract of the dust mite Blomia tropicalis (Bt). BACKGROUND: Bt is an important source of allergens causing allergic diseases in tropical and subtropical regions. mAbs are excellent tools for delineating cross-reactivity between Bt and other mites. MATERIALS AND METHODS: Mice were immunized with extracts of Bt. mAbs were produced by standard techniques. Hybridoma screening was performed by ELISA. Ascitic fluids were produced and partially purified by adsorption chromatography. Reactivity of mAbs against extracts of Bt and Dermatophagoides pteronyssinus (Dp) was analyzed by ELISA, immunoblots and ELISA inhibition. Also, reactivity of mAbs against the putative cysteine protease rBlo t 1 from Bt was tested. RESULTS: Three IgG mAbs were obtained and partially purified. The mAbs reacted with Bt by ELISA. In immunoblots, mAbs recognized two protein components of 29 and 35 KD. Also, the mAbs reacted with Dp extracts by ELISA, and the same sized components were detected in immunoblots. In competitive ELISA, Dp extract reduced in 62% the reactivity with Bt antigens, and Bt extract produced a maximum reduction of reactivity against Dp antigens of 83%. The mAbs recognized rBlo t1. The homology between Blo t1 and the proteins recognized by the mAbs was high (90%) as the inhibition assays demonstrated. CONCLUSIONS: The cross-reactivity between Dp and Bp could be related with the presence of proteins as their respective cysteine proteases. The produced mAbs have proven to facilitate the identification of antigens of Bt and to determine the possible cross-reactivity between Bt and other common mites of the acarofauna of tropical and subtropical countries where Bt is commonly found.

Frecuencia de caries de la infancia temprana en una muestra de niños de 1 a 4 años de Santafé de Bogotá y exploración del riesgo de la lactancia prolongada, perfil familiar y entorno socioeconómico / Dental caries frequency of the early childhood in a sample of children form 1 to 4 years old in Bogota city and exploration of the risk of the prolonged lactation, familiar profile and socioeconomic surroundings

Propósito: El propósito del presente estudio fue determinar el porcentaje de niños entre 1 y 4 años de edad en una muestra de Santafé de Bogotá, que están afectados por la caries de la infancia temprana (CIT) y establecer la asociación de ésta con el perfil familiar, entorno socioeconómico, conocimiento del cuidado oral y lactancia prolongada. Método: 396 niós de 1 a 4 aós de edad en Santafé de Bogotá fueron examinados, y padres o acudientes entrevistados por tres examinadores previamente calibrados. Los posibles factores de riesgos se analizaron estableciendo la razón de disparidad (O.R) y la prueba de chi cuadrado, p<0.05. Las variables examinadas incluyeron aspectos clínicos, entorno socioeconómico, perfil familiar, conocimiento sobre salud oral y hábitos de lactancia. Resultados: El porcentaje de CIT fue de 11.3 para la población examinada. De la muestra total de el 86.6 tuvo lactancia prolongada, y solamente un 13.6 de este grupo presentó CIT. Se halló una asociación significativa entre CIT y género, estrato socioeconómico bajo, nivel educativo ninguno-primaria de los padres , forma de corrección física, pocos conocimientos sobre salud oral, y consulta al odontólogo para tratamiento. No se encontró una asociación entre CIT y perfil familiar. Conclusiones: El 11.3 de los niños presentaron caries de la infancia temprana en Santafé de Bogotá. La variable de mayor asociación se encontró entre CIT, nivel educativo de la madre y entorno socioeconómico. La asociación entre lactancia prolongada y caries de la infancia temprana fue más débil que las variables mencionadas, aunque hubo significancia estadística. Las variables en general, se encontraron en desventaja para el estrato socioeconómico bajo. El tratamiento y prevención de la caries de la infancia temprana deben tener un componente socioambiental , con programas dirigidos principalmente a los estratos menos favorecidos.

Complicaciones de la otitis media crónica: experiencia en el Hospital Universitario de Caracas / Chronic otitis media complications: experience at Hospital Universitario de Caracas

La otitis media cronica es un motivo frecuente de consulta en los servicios de otorrinolaringologia y medicina general. La identificación de las complicaciones locales, regionales y a distancia deben hacerse en estadios precoces para evitar secuelas importantes asi como para disminuir su mortalidad. En esta investigación presentamos 358 casos hospitalizados en el Servicio de Otorrinolaringologia del Hospital Universitario de Caracas. Se analizan motivos de consulta, hallazgos microbiologicos e intraoperatorios, secuelas y mortalidad

Evaluacion de la calidad de los reactivos que se utilizan en la tecnica de contrainmunoelectroforesis para la determinacion de anticuerpos antirrabicos / Evaluation of the quality of the reagents employed in the counterimmunoelectrophoresis technique for the determination of rabies antibodies

En este estudio se comprobo que el Instituto Butantan produce antigenos y sueros indicadores que se pueden utilizar con exito en la prueba de contrainmunoelectroforesis para titular anticuerpos antirrabicos en personas inmunizadas. No se pudieron demostrar diferencias estadisticamente significativas entre los resultados de las pruebas de estandarizacion realizadas en el Instituto Butantan y las pruebas de control de referencia llevadas a cabo en el Centro Panamericano de Zoonosis. Se propone que el Instituto Butantan produzca y distribuya a nivel nacional los reactivos para que los laboratorios de diagnostico apliquen la tecnica de contrainmunoelectroforesis para la determinacion de anticuerpos antirrabicos.

Inmunizacion de terneros con vacuna antirrabica de cerebro de raton lactante. / Immunization of calves with rabies vaccine of suckling mouse brain

En este trabajo se presentan los resultados obtenidos en un estudio de duracion de inmunidad en terneros inmunizados con vacuna antirrabica de cerebro de raton lactante suplementada con hidroxido de aluminio. El 100% de los terneros vacunados presentaron anticuerpos antirrabicos circulantes a los diez dias despues de la vacunacion; los titulos comenzaron a descender 90 dias despues de la inmunizacion. De los 15 terneros desafiados un ano despues de la inmunizacion, 5 (33%) no tenian anticuerpos detectables en la dilucion 1:5 de sus sueros. Todos resistieron el desafio que mato al 75% (3/4) de los testigos no vacunados. Se discute la edad minima para la vacunacion antirrabica de terneros con vacuna de cerebro de raton lactante y la necesidad de revacunacion de los mismos