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Mite Extracts (mite + extract)

Distribution by Scientific Domains

Medical Sciences	85%

Selected Abstracts

Isolation and characterisation of a 13.8-kDa bacteriolytic enzyme from house dust mite extracts: homology with prokaryotic proteins suggests that the enzyme could be bacterially derived

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2002
Leslie T. Mathaba
Abstract Bacteriolytic activity was detected in extracts of whole mite and spent growth medium (SGM) from the clinically important Dermatophagoides pteronyssinus and Dermatophagoides farinae mites and was most abundant in whole mite extract. Gram-positive organisms Micrococcus lysodeikticus, Bacillus megaterium and Listeria monocytogenes were preferentially lysed and the lytic activity was enhanced by thiols, destroyed by mite proteases, inhibited by HgCl2 and high concentrations of NaCl but was resistant to heat and acid treatment. Substrate SDS,PAGE analysis indicated the presence of several lytic enzymes, two of which were isolated from D. pteronyssinus spent growth medium extract by hydroxyapatite chromatography. The N-terminal amino acid sequence of one of them was then used in PCR-based cloning studies. The complete amino acid sequence of this protein was determined and cDNA found to encode a 130-amino acid residue mature protein with a 20-amino acid leader sequence. The deduced protein demonstrated sequence similarity with the C-terminal regions of a group of bacterial proteins belonging to the P60 superfamily. These data suggest that the enzyme is derived from bacteria within the mites rather than from mites per se. [source]

Airway eosinophilia is not a requirement for allergen-induced airway hyperresponsiveness

CLINICAL & EXPERIMENTAL ALLERGY, Issue 1 2000
Tournoy
Background House dust mites (HDMs) are the major source of perennial allergens causing human allergic asthma. Animal models mimicking as closely as possible the allergic features observed in human asthma are therefore interesting tools for studying the immunological and pathophysiological mechanisms involved. Especially the role of eosinophils and allergen-specific immunoglobulin (Ig) E in the pathophysiology of airway hyperresponsiveness (AHR) remains a subject of intense debate. Objective To develop a mouse model of allergic airway inflammation and hyperresponsiveness based on the use of purified house dust mite allergen (Der p 1) as clinical relevant allergen. Furthermore, we studied the effects of low dose allergen exposure on the airway eosinophilia and AHR. Methods On day 0, C57Bl/6 mice were immunized with purified Der p 1 intraperitoneally. From day 14,20, the mice were exposed daily to a 30-min aerosol of different concentrations of house dust mite extract. Results Mice, actively immunized with Der p 1 and subsequently exposed to HDM aerosols, developed AHR, eosinophil infiltration of the airways and allergen-specific IgE. Moreover, lowering the concentration of the HDM aerosol also induced AHR and IgE without apparent eosinophil influx into the airways. Der p 1-sensitized mice exposed to PBS produced IgE, but did not show AHR or eosinophil influx. Conclusion This in vivo model of HDM-induced allergic airway changes suggests that AHR is not related to either eosinophil influx or allergen-specific serum IgE, thereby reducing the importance of these factors as essential elements for allergic AHR. [source]

Isolation and characterisation of a 13.8-kDa bacteriolytic enzyme from house dust mite extracts: homology with prokaryotic proteins suggests that the enzyme could be bacterially derived

Characterization and comparison of commercially available mite extracts for in vivo diagnosis

ALLERGY, Issue 2 2010
B. Brunetto
To cite this article: Brunetto B, Tinghino R, Braschi MC, Antonicelli L, Pini C, Iacovacci P. Characterization and comparison of commercially available mite extracts for in vivo diagnosis. Allergy 2010; 65: 184,190. Abstract Background:, Assessment of sensitization by allergen-specific IgE testing and skin prick testing (SPT) are primary tools in routine clinical diagnosis of allergies. To perform a correct diagnosis, it is critical that the allergen reagent used contains an adequate amount of all relevant components. This study aimed at evaluating commercially available mite extracts for in vivo diagnosis from eight manufacturers. Methods:, Eight extracts from Dermatophagoides pteronyssinus and eight from Dermatophagoides farinae were analysed for total protein content by Bradford and for major allergen content by ELISA. SDS-PAGE, immunoblotting and SPT were also carried out. Results:, The protein amount ranged from 27.7 ,g/ml extract to 361.1 ,g/ml (D. pteronyssinus) and from 20.3 to 353.0 ,g/ml (D. farinae). In regards major allergen concentration, Der p 1 ranged from 9.6 to 36.2 ,g/ml, Der f 1 26.5,196.1 ,g/ml, mite group 2 0.7,31.7 ,g/ml in D. pteronyssinus and 1.3,10.4 ,g/ml in D. farinae. SDS-PAGE experiments showed that some components are poorly represented or absent in extracts from most manufacturers. Similar results were obtained by IgE-immunoblotting and SPT with 10 mite allergic patients confirmed a broad spectrum of reactivity of the extracts in the same subject. Conclusions:, Immunochemical analysis showed a heterogeneous amount of component/s among mite extracts from different manufacturers. These data were confirmed by in vivo testing, suggesting that, for some of the patient tested, the absence of relevant allergens could strongly affect the diagnosis. [source]

The importance of starch and sucrose digestion in nutritive biology of synanthropic acaridid mites: ,-Amylases and ,-glucosidases are suitable targets for inhibitor-based strategies of mite control,

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 3 2009
Tomas Erban
Abstract The adaptation of nine species of mites that infest stored products for starch utilization was tested by (1) enzymatic analysis using feces and whole mite extracts, (2) biotests, and (3) inhibition experiments. Acarus siro, Aleuroglyphus ovatus, and Tyroborus lini were associated with the starch-type substrates and maltose, with higher enzymatic activities observed in whole mite extracts. Lepidoglyphus destructor was associated with the same substrates but had higher activities in feces. Dermatophagoides farinae, Chortoglyphus arcuatus, and Caloglyphus redickorzevi were associated with sucrose. Tyrophagus putrescentiae and Carpoglyphus lactis had low or intermediate enzymatic activity on the tested substrates. Biotests on starch additive diets showed accelerated growth of species associated with the starch-type substrates. The inhibitor acarbose suppressed starch hydrolysis and growth of the mites. We suggest that the species with higher starch hydrolytic activity in feces were more tolerant to acarbose, and ,-amylase and ,-glucosidase of synanthropic mites are suitable targets for inhibitor-based strategies of mite control. © 2009 Wiley Periodicals, Inc. [source]

Systemic reactions to immunotherapy: influence of composition and manufacturer

CLINICAL & EXPERIMENTAL ALLERGY, Issue 4 2003
G. Gastaminza
Summary Background Although immunotherapy clearly demonstrated the benefit of reducing allergic symptoms, it has the drawback of adverse events, mainly systemic reactions that could be very inconvenient for patients and even life-threatening. Objective The aim of the present study was to assess the incidence of systemic reactions to immunotherapy in a large number of patients, and its potential relationship with the characteristics of therapy, such as allergen composition or manufacturing laboratory. Methods This study analysed the administration of specific immunotherapy during a period of 5 years, involving 1212 patients affected by respiratory hypersensitivity or hymenoptera venom anaphylaxis. Commercial extracts were supplied by five different laboratories. All the patients were attended at an out-clinic immunotherapy unit by the same experienced staff. Immunotherapy was given following a conventional schedule, modified according the usual recommendations. Results A total of 250 adverse reactions have been recorded, resulting in a frequency of 0.84% over the total number of injections. Seventy-nine of them (32%) were systemic reactions (0.27% SR/injection). The 79 systemic reactions were observed in 60 patients (5% of the patients). The frequency of systemic reactions was significantly lower (P < 0.01) on the group of mites than on the other groups. The frequency of systemic reactions varies according to the manufacturing laboratory. In the case of mite extracts, although one of the laboratories had a lower frequency of adverse systemic reactions, it did not reach the level of statistical significance. However, in relation to pollen extracts, preparations of one of the manufacturers had a significantly lower frequency of systemic reactions. Concerning the time of occurrence, 27% of systemic reactions were delayed, thus they appeared at least 30 min after the vaccine injection, most of them due to pollen extracts. Conclusion This is a preliminary study to evaluate the factors that could facilitate the appearance of systemic reactions demonstrating that not only the composition but also the manufacturer is connected to systemic reactions. Although further studies are needed to clearly establish the influence of manufacturer on frequency and time of appearance of systemic reactions, it seems necessary to reach a wide consensus on allergen extract standardization methods. [source]

Potato lectin activates basophils and mast cells of atopic subjects by its interaction with core chitobiose of cell-bound non-specific immunoglobulin E

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2007
S. N. Pramod
Summary A major factor in non-allergic food hypersensitivity could be the interaction of dietary lectins with mast cells and basophils. Because immunoglobulin E (IgE) contains 10,12% carbohydrates, lectins can activate and degranulate these cells by cross-linking the glycans of cell-bound IgE. The present objective focuses on the effect of potato lectin (Solanum tuberosum agglutinin; STA) for its ability to release histamine from basophils in vitro and mast cells in vivo from non-atopic and atopic subjects. In this study, subjects were selected randomly based on case history and skin prick test responses with food, pollen and house dust mite extracts. Skin prick test (SPT) was performed with STA at 100 µg/ml concentration. Histamine release was performed using leucocytes from non-atopic and atopic subjects and rat peritoneal exudate cells. SPT on 110 atopic subjects using STA showed 39 subjects positive (35%); however, none showed STA-specific IgE; among 20 non-atopic subjects, none were positive by SPT. Maximal histamine release was found to be 65% in atopic subjects (n = 7) compared to 28% in non-atopic subjects (n = 5); the release was inhibited specifically by oligomers of N -acetylglucosamine and correlates well with serum total IgE levels (R2 = 0·923). Binding of STA to N -linked glycoproteins (horseradish peroxidase, avidin and IgG) was positive by dot blot and binding assay. As potato lectin activates and degranulates both mast cells and basophils by interacting with the chitobiose core of IgE glycans, higher intake of potato may increase the clinical symptoms as a result of non-allergic food hypersensitivity in atopic subjects. [source]