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PubMed1999

Cloning and expression of Der f 6, a serine protease allergen from the house dust mite, Dermatophagoides farinae.

House dust mite allergen is thought to be a major cause of asthma. Characterization of these allergen molecules is therefore an important step for the development of effective diagnostic and therapeutic agents against mite-associated allergic disorders. Here we report molecular cloning and expression of the group 6 (chymotrypsin-like) allergen from the house dust mite, Dermatophagoides farinae. Sequencing analysis indicates that cloned cDNA, designated Der f 6, encodes a 279 amino acid polypeptide which conserves a primary structure characteristic for chymotrypsin-like serine proteases found in mammals. Recombinant Der f 6 expressed in Escherichia coli bound IgE in a pool made of 20 sera, and induced histamine release from patients' peripheral blood cells.

Allergens↗
PubMed1997

Purification and characterization of a 94 KD high molecular weight allergen from house dust mite, Dermatophagoides pteronyssinus.

House dust mite allergens from Dermatophagoides pteronyssinus is an important cause of severe allergic asthma and rhinitis in many countries. Although several low to medium molecular weight allergens had been well characterized, limited studies on the high molecular weight IgE-binding components were reported. In this study, a 94 kD high molecular weight allergen from crude mite body extract of D. pteronyssinus was purified and characterized. Monoclonal antibody (mAb) affinity chromatography and high performance liquid chromatography were used to purify 94 kD allergen. Its antigenicity and allergenicity were confirmed by in vitro and in vivo studies. Two mAbs 2205-3.45 and 2220-7.25 specific to 94 kD high molecular weight component of D. pteronyssinus were generated. The epitopes recognized by these mAbs were species-specific. Enzyme-linked immunosorbent assay (ELISA) of IgE reactivity in the sera from 40 asthmatic children allergic to D. pteronyssinus showed that 37.5% of them had significantly higher optical density values (range 0.011 to 0.452) than normal (range 0.013 to 0.035). In in vivo skin test showed that 9 out of 20 (45%) asthmatic children were positive to 94 kD allergen. The results demonstrate that 94 kD high molecular weight component is an important allergen existing in house dust mite in Taiwan.

Allergens↗
PubMedDate not supplied

[An experimental study of the capacity of the rat mite Ornithonyssus bacoti (Hirst, 1913) to ingest, maintain and transmit Borrelia].

For the first time a possibility of the gamasina mites' O. bacoti participation in Lyme disease spirochetes' circulation has been demonstrated. It has been experimentally shown that Borrelia burgdorferi s.l. are received by O. bacoti, survive in them for at least 21 days and are transmitted to white mice through mites' bites. Mice's infestation has occurred in 23% of cases. It is suggested that other bloodsucking gamasina mites inhabiting the Lyme borreliosis reservoir rodents nests may be capable of participating in borrelia circulation in the Lyme disease endemic areas.

Animals↗
PubMed2000

Oribatid mites (Acari, Oribatida) as intermediate hosts of tapeworms of the Family Anoplocephalidae (Cestoda) and the transmission of Moniezia expansa cysticercoids in South Africa.

Six species of adult oribatid mites (Galumna racilis, Kilimabates pilosus, Kilimabates sp., Scheloribates fusifer, Muliercula ngoyensis and Zygoribatula undulata) and two immature stages belonging to the superfamilies Galumnoidea and Ceratozetoidea were isolated from a lawn (mixed Pennisetum and Cynodon spp.) at Onderstepoort Veterinary Institute, South Africa. The mites were subsequently used in an infection trial using Moniezia expansa eggs. Tapeworm cysticercoids were recovered in G. racilis, K. pilosus, Kilimabates sp., S. fusifer, M. ngoyensis and Z. undulata, as well as in immatures of Ceratozetoidea. The percentage of infected mites was 7,6, 6,3, 16,4, 66,7, 57,1, 60,0 and 46,7% respectively. Immatures of Galumnoidea did not become infected. The highest number of cysticercoids isolated from one individual was six from an adult S. fusifer.

Animals↗
PubMed2000

Household distribution of house dust mite in central Taiwan.

House dust mite (HDM) is a common inhalant allergen which can precipitate atopic disease episodes including asthma and allergic rhinitis. However, the relationship between HDM and asthma in subtropical regions of Asia, which may be affected by differences in climate and environmental variables, has not been widely studied. To assess this relation in the subtropical region of central Taiwan, we collected HDM samples from the houses of eight asthmatic patients as well as four normal subjects over a 1-year period. HDMs were collected by vacuum from the following four areas: living room floor, sofa, the top surface of child's mattress and bedroom floor. The mite concentrations, site distribution, seasonal variation, individual species and correlation with asthmatic attacks were studied. The HDM concentration had a seasonal variation, with the highest concentrations noted from July to November with gradually decrease from December to June. Among the four areas of collection, the highest concentration of mites was found on the child's mattress (p < 0.05). Dermatophagoides pteronyssinus was the dominant species (77%) and Dermatophagoides farinae was the second (13%). Our data showed that: 1. The highest concentrations of HDM occurred during the period from July to November. 2. The child's mattress was the household region with the highest percentage of HDM and thus should be considered of great concern as a likely source of the exacerbation of asthma. 3. D. pteronyssinus was the dominant species.

Animals↗
PubMed2002

House dust mite allergen levels in individual bedding components in New Zealand.

AIMS: House dust mite allergen (Der p 1) levels are high in New Zealand and bedding Der p 1 levels have been shown to be associated with the clinical severity of asthma. The aim of this study was to measure Der p 1 levels in synthetic and feather duvets and other individual bedding items, and to examine factors affecting these levels. METHODS: Reservoir dust samples were collected and analysed for Der p 1 content by ELISA from 65 duvets, 81 pillows, and 65 mattresses of 34 children and 31 adults in 34 households. RESULTS: Der p 1 geometric mean levels (95% confidence interval) were: 13.4 microg/g (9.5-18.9) in pillows; 29.4 microg/g (19.8-43.5) in duvets; and 53.8 microg/g (39.4-73.4) in mattresses. Synthetic pillows and duvets yielded significantly more Der p 1 than feather pillows and duvets (about 7-fold and 15-fold respectively). The presence of under-bedding resulted in significantly higher pillow and duvet Der p 1 levels. Mattresses >10 years old had significantly higher Der p 1 levels. CONCLUSIONS: Synthetic pillows and duvets contain higher levels of Der p 1 than feather pillows and duvets. Advise for house dust mite sensitized individuals to use synthetic bedding does not prevent house dust mite allergen exposure.

Allergens↗
PubMed1975

A successful method for mass culture of the house dust mite, Dermatophagoides pteronyssinus (Troussart, 1897).

Comparative studies have been carried out to find out an optimum condition for efficient mass culture of Dermatophagoides pteronyssinus (Troussart, 1897), the most dominant species of the house dust mites. Among various food materials tested for culture media, the mixture composed of 2 parts of powdered laboratory animal food, 2 parts of dried yeast and 1 part of dried fish powder was found to be most fitted. The humidity content of the medium was best when adjusted to 16% beforehand and thin layer of the food medium was prepared in Roux's-bottle with a paper plug. The plug of the bottle was opened once a week and the medium was mixed thoroughly by shaking to prevent clotting. When about 15,000 mites were inoculated into 100 g of culture media, the highest yield was obtained with relative humidity regulated at 75% and the temperature at 25 degrees C after 12 weeks of incubation. Purified mites were separated from culture media by floatation with saturated NaCl solution and the average yield of the mice was 2 to 3 g in wet weight per 100 g of the food mixture.

Animals↗
PubMed1976

[Allergen-specific immunoglobulin E in the serum (RAST), skin tests and mucosa provocation tests using house dust and house mite extract in rhinopathy and bronchial asthma].

Allergy against house dust and house dust mite was examined by RAST, skin and provocation test, with not identical allergen extracts. 50 patients with allergic rhinitis showed insufficient RAST results with house dust, better results for house dust mite. 65 patients with allergic asthma bronchiale presented satisfying results with house dust, good results with house dust mite. Recommendations are given for the application of RAST in the diagnosis of allergy.

Allergens↗
PubMed1976

House dust mites and infant-use sheepskins.

A study of dust mite populations in infant-use lambskin and other bedding has showm more mites present in the latter. Regular vacuuming of the lambskin greatly reduces the mite population on it, but cannot prevent recolonization from adjacent areas.

Bedding and Linens↗
PubMed1992

Bronchial inflammation in mite-sensitive asthmatic subjects after 5 years of specific immunotherapy.

We examined the pattern and degree of the inflammatory process in bronchial biopsy specimens taken by fiberoptic bronchoscopy in eight asthmatic subjects (two women aged 19-38 years) after 5 years of specific immunotherapy (SIT) to mite extracts (SIT group). At the time of study, they received a maintenance dose of mite-extracts (last subcutaneous administration 3 weeks before bronchoscopy). Results were compared with those found in eight matched mite-sensitive subjects with stable asthma (two women aged 19-36 years; non-SIT group) and in eight healthy individuals (four women aged 22-29 years; control group). Bronchial biopsy specimens were fixed in periodate-lysine-paraformaldehyde, embedded in glycol methacrylate, and stained with hematoxylin-eosin and 2% toluidine blue. Number of eosinophils, mast cells, and total nucleated cells were counted separately in the epithelium and lamina propria by light microscopy and expressed as cells/high power field. Within the epithelium, eosinophil and mast cell counts in SIT and non-SIT groups were significantly higher compared to controls, whereas total cell counts were not statistically different. Within the lamina propria, total cell count in SIT and non-SIT groups was significantly higher compared with the control group, whereas mast cells were similar. The number of eosinophils in both SIT and non-SIT groups was higher compared with controls; however this reached statistical significance only in SIT-groups. Comparison between the two groups of asthmatics did not show any significant difference for any cell counts.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Sensitization to house dust mites: importance and possibilities of allergen elimination].

House-dust mite allergy (Dermatophagoides pteronissinus and Dermatophagoides farinae) is an important causative factor for allergic asthma or rhinitis in children. There is a clear relationship between the degree of allergen exposure and the subsequent development of asthma or the risk of sensitisation. It is therefore useful to know how intensive a patient is exposed to house-dust allergen. This can be managed either by counting all mites in the dust, by measuring of the content of Der p I and Der f I (major antigens of the two mites) per gram dust or using the Acarex test. These methods are also suitable for the control of sanitation measurements, e.g. avoidance of all dust sources in the bedroom and living-room, use of suitable materials for bedding, application of acaricide products and covering mattresses with polyurethane-coated materials.

Allergens↗
PubMed1992

Is a trypsin-like protease of mites a Der f III allergen?

A trypsin-like protease was purified from mite (Dermatophagoides farinae) fecal extract. In SDS-PAGE, the mite trypsin-like protease showed a single band at 34 kD. The purified trypsin-like protease possessed potent allergenic activity. Both the twenty N-terminal amino acid sequence and the amino acid composition of the purified protease were very similar to those of Der f III. These data strongly suggest that the trypsin-like protease in the mite is a Der f III allergen.

Allergens↗
PubMed2003

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.

Allergens↗
PubMed2004

[Control strategies against Varroa mites].

In many cases, the easiest way to control a pest or a pathogen is to resort to chemical treatments. In the short period this option is often the most convenient economically and usually does not require refined knowledge of the biology of the pest. Many efforts have been directed to develop chemical treatments against Varroa destructor Anderson & Trueman. Nowadays, product based on organic acids, essential oils, pyrethroids, organophosphate, and formamidine are available. Resistance is serious problem in the chemotherapy of parasites and pathogens of the honeybee. High-level resistance to several active substances (the pyrethroids acrinathrin, flumethrin, fluvalinate; the organophosphate coumaphos; the formamidine amitraz) was detected with laboratory assays in different varroa populations and caused failure of the control in the field. At the end of the '80s, products based on pyrethroids, very effective against the mite, but without any appreciable side effect on bees, became available. Resistance to fluvalinate in Italy and later in other countries caused serious damage to beekeeping; early detection was crucial to reduce losses. The problem of developing suitable treatments was difficult in the case of the varroa mite because most substances active against V. destructor have unacceptable side effects on bees. The idea that the mite could be controlled indefinitely with these strategies began to gain ground.

Animals↗
PubMed1979

[Immunological investigations of house-dust and house-dust mites. Part III. A simplified basophil degranulation test. Preliminary communication (author's transl)].

The basophil degranulation test (BDT) after Shelley has been simplified and tried on patients allergic to house-dust or to house-dust mites. All 20 patients reacted to the mite extracts and 19 out of 20 to the house dust extracts. Out of 20 control persons 17 had negative results to the mite extract and 16 to the house-dust extract. The advantages of this new simplified method are discussed.

Basophils↗
PubMed2005

An outbreak of rat mite dermatitis in an animal research facility.

We describe an outbreak of rat mite dermatitis that affected 15 employees of an animal research facility. Cases of rat mite dermatitis are infrequently reported, and outbreaks are reported even less. Our case series demonstrates that in contrast to most prior outbreaks, rat mite dermatitis may occur even in modern, well-maintained physical surroundings and thus remains a relevant diagnosis today.

Adult↗
PubMedDate not supplied

[Extra-oral digestion and the problem of parasitism in Parasitengona mites (Acariformes)].

An analysis of the extra-oral digestion in Parasitengona being a highly specialized group of Acariform mites is carried out from the viewpoint of functional morphology and ecology. The significance of the extra-oral digestion in the life strategy of these mites and their larval parasitism is also evaluated. The morphological pre-adaptations of this mode of feeding as well as its probable evolutionary consequences are demonstrated by an example of trombiculid mites (Trombiculidae). It is shown, in particular, that parasitism in general may be considered as a particular life scenario implying that the feeding preferences of the organism are evolutionary formed in a close association with other organisms, which provide a parasite with a feeding substrate mainly already prepared for utilization. Based on this assumption, all Parasitengona, including both larval and post-larval instars, irrespectively of the size of their potential victim, preferably should not be considered as parasites, but as micro-predators.

Adaptation, Physiological↗
PubMed1991

Clinical study on value and limitations of subcutaneous immunotherapy (specific hyposensitization) in allergic asthma to house dust mite, based on a personal algorithm of selection.

Subcutaneous immunotherapy (SI) was administered to 148 patients (76 males, 72 females; aged 6-48 years) with allergic asthma to house dust and mites (D. pteronyssinus). Skin tests were positive to both allergens. Treatment was performed with allergenic extracts of house dust (61 patients) and allergenic extracts to house dust mites (87 patients) over a period of at least one year (mean 2.8 years). The selection criteria were: past history (including positive natural provocation test), intense skin response to mite extracts (> 10 mm) and favorable response to therapy with disodium cromoglycate and/or ketotifen. None of the patients selected presented long-lasting infections or other complications in the evolution of asthma. During treatment it was necessary in 46% of the patients to add other drugs such as mast cell degranulators or corticosteroid products over short periods when occasional cases of respiratory infections occurred. Favorable results were obtained in 86% of the cases, with the best results being obtained in patients who exactly fulfilled the selection criteria and in whom SI was administered over a period of at least 3 years.

Adolescent↗