Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MITES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,099 records · Page 61Linked to original sources
PubMed1997

Human T cell responses to recombinant mite antigens of Dermatophagoides farinae.

We studied T cell responses to four glutathione S transferase (GST)-fused mite antigens prepared in our laboratory using peripheral blood lymphocytes from mite-sensitive patients with bronchial asthma. Of the four recombinant antigens, purified GST-Mag3 had the strongest ability to cause patients' lymphocytes to proliferate, and its potency was almost comparable to that of crude mite bodies (Dfb) and faeces (Dff) antigens and a purified major antigen, Der f 2. The responder lymphocytes were mainly T cells, because the proliferative response was depleted by the treatment of lymphocytes with anti-CD3 antibody and complement, but not with anti-CD20 antibody and complement. The responsiveness of lymphocytes to GST-Mag3 correlated with that to Der f 2, but GST-Mag3 displayed slightly higher activity to stimulate lymphocytes than Der f 2. Simultaneously, the levels of Dff- and GST-Mag3-specific IgE antibodies correlated with the responsiveness of lymphocytes to GST-Mag3. These results suggest that Mag3 is a new valuable antigen for the response of T cell proliferation in mite-sensitive patients.

Allergens↗
PubMed2002

Validity of species status of the parasitic mite Otodectes cynotis.

A combined molecular and phenotypic approach was used to determine whether ear mites of the genus Otodectes (Acari: Psoroptidae) belong to a single species. The second internal transcribed spacer (ITS 2) of the rDNA of 16 isolates from 11 cats, two dogs, one arctic fox and two ferrets originating from four different continents was characterized. In addition, mites from dog, cat and arctic fox were investigated morphologically. Sequence comparisons revealed five different, but closely related genotypes which did not segregate according to host species or geographical origin. Morphologically, mites of the three host species did not differ significantly in their body or leg sizes. These investigations support the view that ear mites of the genus Otodectes from different hosts and geographical origins belong to a single species, Otodectes cynotis (Hering).

Animals↗
PubMed2003

Lep d 2 polymorphisms in wild and cultured Lepidoglyphus destructor mites.

We have previously cloned, expressed and characterized two variants of the major allergen Lep d 2 from cultured Lepidoglyphus destructor mites. These variants, Lep d 2.0101 and Lep d 2.0201, differ at 13 amino acid positions. In this study we investigated Lep d 2 sequence diversity between wild and cultured mites. PCR, Southern blot and DNA sequence analysis revealed the presence of two different Lep d 2 genes, one with and one without an intron. In addition, two new variants of Lep d 2, Lep d 2.0102 and Lep d 2.0202, were found at different frequencies in wild and cultured mites. When we expressed the Lep d 2 variants and compared their IgE binding properties by ELISA inhibition, we found that Lep d 2.0102 was a more potent inhibitor than Lep d 2.0101, and to a lesser extent Lep d 2.0202 was more potent than Lep d 2.0201. Long-term cultures of peripheral blood mononuclear cells were used to assess the ability of the expressed Lep d 2 variants to induce cytokine release. Although cells from different individuals released different amounts of interferon-gamma and interleukin-5, no consistent cytokine release pattern could be linked to any specific Lep d 2 variant. In conclusion, we show that both cultured and wild Lepidoglyphus destructor mites contain the same pattern of polymorphism. Furthermore, this Lep d 2 sequence diversity seems not to have any significant impact on the allergens IgE binding or its ability to induce T cell cytokine release.

Allergens↗
PubMedDate not supplied

Immediate and delayed hypersensitivity to mite antigens in atopic dermatitis.

Atopic dermatitis (AD) is a common disorder and appears to be on the increase, especially among children. It was thought at first to be a manifestation of immediate hypersensitivity, but it is now known that delayed hypersensitivity also plays an important role. Sensitivity to mite antigens is found in 20% to 60% of patients when immediate hypersensitivity is evaluated by the detection of specific IgE antibodies and prick tests, and in 30% to 50% of patients when delayed hypersensitivity is studied by patch testing. A prospective randomized study was carried out in the pediatric dermatology clinic on a sample of 51 children under 15 years of age. A prevalence of immediate and delayed hypersensitivity to mites, like that described for other populations, was found. It was further found that there was a positive association, not described in the literature, between the younger age groups and delayed hypersensitivity to mite antigens, while the opposite was true for immediate hypersensitivity. We believe that patch tests with airborne allergens, specifically mites, should be part of the protocol for assessing children with AD, particularly in the younger age groups.

Age of Onset↗
PubMed2001

[Exposure status of East and West German households with house dust mites and fungi].

The interrelation between biological pollution of indoor spaces and health disorders, allergic symptoms and health issues in general is well known. Besides animal epithelia, the exposure to house dust mites and mould fungi is considered a serious risk factor. In the scope of a comparative study involving school beginners in East and West Germany (launched in 1991), dust was vacuumed from a total of 218 mattresses of children's beds and checked for their content of house dust mites and mould fungi. This investigation aimed at assessing the degree of exposure, to determine regional differences, if any, and to uncover the correlation between exposure and symptoms. Dust mite infestation was highest in the small town of Borken in Westphalia (in 86% of the specimens > 2 micrograms mite allergens/g of dust) and lowest in Magdeburg in Saxony-Anhalt (55.3%). Total concentrations of mould fungi varied from 1.4 x 10(3) CFU/g of dust and 300 x 10(3) CFU/g of dust with a geometric mean of 26.5 x 10(3) CFU/g of dust. A total of 41 different genera/species were identified. Most frequent were the following genera: Penicillium, Eurotium, Aspergillus, Alternaria, Epicoccum and Cladosporium. The importance of individual factors influencing was confirmed. Humidity decreases the higher the flat is situated in a building. This partly explains the differences in concentrations between Borken where children live mainly on the ground floor, and the other cities with taller buildings. Spores of mould fungi were discovered more frequently in mattresses from humid flats. An association between biological indoor space factors and some allergological parameters seemed obvious, however, due to the small size of the test group most of them were not significant.

Air Pollution, Indoor↗
PubMed1990

Exposure to house-dust mite allergen (Der p I) and the development of asthma in childhood. A prospective study.

BACKGROUND AND METHODS: Children with asthma commonly have positive skin tests for inhaled allergens, and in the United Kingdom the majority of older children with asthma are sensitized to the house-dust mite. In a cohort of British children at risk for allergic disease because of family history, we investigated prospectively from 1978 to 1989 the relation between exposure to the house-dust mite allergen (Der p I) and the development of sensitization and asthma. RESULTS: Of the 67 children studied in 1989, 35 were atopic (positive skin tests), and 32 were nonatopic. Of the 17 with active asthma, 16 were atopic (P less than 0.005), all of whom were sensitized to the house-dust mite, as judged by positive skin tests and levels of specific IgE antibodies (P less than 0.001). For house-dust samples collected from the homes of 59 of the children in 1979 and from 65 homes in 1989, the geometric means for the highest Der p I exposure were, respectively, 16.1 and 16.8 micrograms per gram of sieved dust. There was a trend toward an increasing degree of sensitization at the age of 11 with greater exposure at the age of 1 (P = 0.062). All but one of the children with asthma at the age of 11 had been exposed at 1 year of age to more than 10 micrograms of Der p I per gram of dust; for this exposure, the relative risk of asthma was 4.8 (P = 0.05). The age at which the first episode of wheezing occurred was inversely related to the level of exposure at the age of 1 for all children (P = 0.015), but especially for the atopic children (r = -0.66, P = 0.001). CONCLUSIONS: In addition to genetic factors, exposure in early childhood to house-dust mite allergens is an important determinant of the subsequent development of asthma.

Age Factors↗
PubMed2000

The stability of house dust mite allergens in glycerinated extracts.

BACKGROUND: Mite allergen vaccines are important diagnostic and immunotherapeutic reagents. Previous studies on mite allergen stability under different storage conditions have yielded contradictory results. OBJECTIVE: We sought to compare, over a 12-month period, the stability of mite allergens reconstituted in 50% glycerol and stored at different temperatures and to examine the role of protease inhibitors in enhancing allergen stability. METHODS: Lyophilized allergen extracts were reconstituted in 50% glycerol, with and without protease inhibitors, and stored at -70 degrees C, -20 degrees C, 4 degrees C, or 37 degrees C for 12 months. At 6 and 12 months, the extracts were compared with freshly dissolved extracts by competition ELISA with pooled allergic sera, 2-site ELISA with mite-specific mAbs, and immunoblot analyses. RESULTS: The overall potencies of the stored extracts measured by competition ELISA were stable at -20 degrees C and 4 degrees C. As determined by means of the immunoblot and 2-site ELISA, Der f 1 levels decreased at 4 degrees C. Levels of Der f 2, Der p 1, and Der p 2 decreased in at least one of the allergen-specific assays. Storage at 37 degrees C led to overall loss of potency and allergen content, whereas storage at -70 degrees C was associated with a moderate loss of potency that increased with multiple freeze-thaw cycles. Protease inhibitors had no effect on allergen stability. CONCLUSION: Although overall potency of the extracts, as measured by competition ELISA, was preserved at -20 degrees C and 4 degrees C, allergen-specific assays indicated loss of allergens. These findings suggest that the competition ELISA is insensitive to decreases in the concentrations of individual allergens.

Animals↗
PubMed2002

Different effects of endotoxin versus mite and cat allergen exposure on T-cell differentiation in infants.

BACKGROUND: Early exposure to bacterial endotoxin has been proposed to protect against allergy development in children. Whether endotoxin is able to direct T-cell differentiation into a predominance of type 1 immunity is still unresolved. OBJECTIVE: We sought to compare the effects of endotoxin and mite and cat allergens on T-cell differentiation in infants. METHODS: In a random population sample of 135 2-year-old children of an ongoing birth-cohort study, peripheral blood CD4+ and CD8+ T-cell subsets were defined by the expression of the chemokine receptors CCR5 and CCR3 as surrogate markers for type 1 and type 2 T cells, respectively. Endotoxin and mite and cat allergens were measured in house dust collected from the mother's mattress at the child's age of 3 months to assess early exposure. RESULTS: In the CD4+ T-cell subset, endotoxin levels were positively associated with high proportions of type 1 CCR5+ cells (odds ratio for fourth exposure quartile [OR(Q4)], 7.68; 95% CI, 1.35-43.75), whereas cat allergen levels were associated with increased proportions of type 2 CCR3+ cells (OR(Q4), 4.07; 95% CI, 1.05-15.85). In contrast to endotoxin, allergen levels were associated with CD8+ T cells, showing an inverse relationship between mite allergen concentrations and high proportions of CCR5+ or CCR3+ cells (CCR5+ cells: OR(Q4), 0.14; 95% CI, 0.03-0.74; CCR3+ cells: OR(Q4), 0.16; 95% CI, 0.03-0.89) and a positive association of cat allergen levels with increased proportions of CCR5+ cells (OR(Q4), 9.24, 95% CI, 1.61-53.10), as well as CCR3+ cells (OR(Q3), 6.64; 95% CI, 1.21-36.51). CONCLUSION: Our results indicate that endotoxin has the potential to promote the development of type 1 CD4+ T cells, whereas mite and cat allergens primarily modify the proportion of CD8+ cells of both types.

Allergens↗
PubMed2002

Involvement of the mannose receptor in the uptake of Der p 1, a major mite allergen, by human dendritic cells.

BACKGROUND: Immature dendritic cells (DCs) take up antigens in peripheral tissues and, after antigen processing, mature to efficiently stimulate T cells in secondary lymph nodes. In allergic airway diseases DCs have been shown to be involved in the induction and maintenance of a T(H)2-type profile. OBJECTIVE: The present study was undertaken to determine pathways of Der p 1 (a house dust mite allergen) uptake by human DCs and to compare Der p 1 uptake between DCs from patients with house dust mite allergy and DCs from healthy donors. METHODS: Monocyte-derived DCs (MD-DCs) were obtained from patients with house dust mite allergy (n = 13) and healthy donors (n = 11). Der p 1 was labeled with rhodamine. Der p 1 uptake by MD-DCs was analyzed by means of flow cytometry and confocal microscopy. RESULTS: Rhodamine- labeled Der p 1 was demonstrated to be taken up by MD-DCs in a dose-, time-, and temperature- dependent manner. The involvement of the mannose receptor (MR) in the Der p 1 uptake was demonstrated by using (1) inhibitors of the MR- mediated endocytosis (mannan and blocking anti-MR mAb), which inhibited the Der p 1 uptake from 40 % to 50 %, and (2) confocal microscopy showing the colocalization of rhodamine-labeled Der p 1 with FITC-dextran. Interestingly, compared with DCs from healthy donors, DCs from allergic patients expressed more MR and were more efficient in Der p 1 uptake. CONCLUSION: These results suggest that the MR could play a key role in the Der p 1 allergen uptake by DCs and in the pathogenesis of allergic diseases in dust mite -sensitive patients.

Adult↗
PubMed2004

Biological control of sciarid and phorid pests of mushroom with predatory mites from the genus Hypoaspis(Acari: Hypoaspidae) and the entomopathogenic nematode Steinernema feltiae.

In small-scale experiments, the predatory mites, Hypoaspis aculeifer (Canestrini) and H. miles Berlese, applied at 700 mites m(-2), and the entomopathogenic nematode, Steinernema feltiae (Filipjev) applied at 3 x 10(-6) nematodes m(-2) controlled sciarids and phorids in mushroom compost and casing substrates. For both mite species, earliest application to the growing substrate following sciarid infestation reduced sciarid emergence. In contrast, later application of each biological control agent provided more effective control of phorid emergence. The behaviour of adult mites suggested that H. aculeifer were more positively geotactic than H. miles although both species could penetrate compost and casing substrates to a depth of 2-12 cm. A majority of S. feltiae nematodes resided at a depth of 2-4 cm in both substrate types. Independent application of H. aculeifer provided more comprehensive control of sciarids and phorids than the other biological agents studied, owing to its better dispersal within compost and casing, and ability to attack larvae of differing ages.

Agaricales↗
PubMed1990

Direct evidence for a functional role of HLA-DRB1 and -DRB3 gene products in the recognition of Dermatophagoides spp. (house dust mite) by helper T lymphocytes.

The contribution of the HLA-DRB1, -B3, and -B5 gene products in the recognition of Dermatophagoides spp. (house dust mite) by helper T cells isolated from an atopic individual (HLA-DRw12, DR7; DRw52b) with perennial rhinitis was investigated. Using a panel of histocompatible and histoincompatible accessory cells, the restriction specificity obtained for a long term T cell suggested that a component of the dust mite reactive repertoire recognized antigen in association with DRB3 gene products. Oligonucleotide DNA typing of the presenting cell panel demonstrated a correlation between the DRw52b allele and T cell responsiveness. Murine fibroblasts expressing DRw52b, but not DRw52a or -c molecules, presented antigen to both the T cell line and cloned T cells (DE26) derived from the line, indicating that the supertypic specificity DRw52b was able to restrict recognition of dust mite antigens. Additional T cell clones (DE9 and DE41) also isolated from the line were restricted by the products of the B1 gene locus (DRw12B1) as determined by murine fibroblasts transfected with the appropriate HLA-DR genes. Clone DE9 was degenerate in its restriction specificity, also recognizing dust mite presented by accessory cells expressing the DR2 subtypes. Presentation by fibroblasts transfected with DRw12B1, DR2Dw2B5 genes and EBV-transformed B cell lines expressing DR2DW21B1 and -B5 indicated that the functional site restricting recognition may be associated with residues 70 and 71 of the DR beta chain helical wall of the antigen combining site. Furthermore, we have recently demonstrated that both T cell clones DE9 and DE26 induce allergen dependent IgE synthesis in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed2004

Effects of greenhouse pesticides on the soil-dwelling predatory mite Stratiolaelaps scimitus (Acari: Mesostigmata: Laelapidae) under laboratory conditions.

Knowledge of the effects of pesticides on biological control agents is required for the successful implementation of integrated pest management (IPM) programs in greenhouse production systems. Laboratory assays were conducted to assess the effects of an acaricide (dicofol), two insecticides (chlorpyrifos and pyriproxyfen), and two fungicides (fosetyl-Al and mefenoxam) on Stratiolaelaps scimitus (Womersley), a soil-dwelling predatory mite widely marketed in North America under the name Hypoaspis miles (Berlese) as a biological control agent of dark-winged fungus gnats (Bradysia spp.). Eggs, larvae, protonymphs, deutonymphs, and adult male and female mites were first assayed using dicofol, an acaricide used in the experiments as a positive control, applied to filter paper in an enclosed arena. Protonymphs were assayed for lethal and sublethal effects against the remaining pesticides at maximum label-recommended rates applied to filter paper, by using dicofol as a positive control and water as a negative control. The larva and protonymph were the life stages most susceptible to dicofol, with estimated 24-h LC50 values of 9 and 26 mg m(-2), respectively. Chlorpyrifos was highly toxic to the protonymphs of S. scimitus, causing >95% mortality after 24-h exposure and 100% mortality after 48 h. In contrast, the insect growth regulator (IGR) pyriproxyfen was much less toxic to protonymphs of S. scimitus; pyriproxyfen caused no significant mortality, compared with <5% mortality in the water control. Mortality caused by the fungicides was also relatively low; 72-h exposure to fosetyl-Al and mefenoxam resulted in 17.4 and 27.5% mortality, respectively. The IGR and fungicides increased the duration of the protonymphal stage by 1.2-1.8-fold, but they had no effect on the duration of subsequent life stages, nor on the duration of preoviposition, oviposition, and postoviposition periods of adult females. Total numbers and viability of eggs laid by mites exposed to the IGR and fungicides did not differ from the negative control, although the average rate of egg production during the oviposition of mites exposed to fosetyl-Al was increased. Pyriproxyfen, fosetyl-Al, and mefenoxam are likely to be compatible with S. scimitus under field conditions, because these pesticides caused little mortality of protonymphs, and they did not negatively affect the development and reproduction of S. scimitus under extreme laboratory conditions. In contrast, the use of chlorpyrifos in conjunction with S. scimitus is not recommended unless more comprehensive testing under semifield or field conditions demonstrates compatibility.

Animals↗
PubMed1989

Evaluating mite (Acari) allergenicity of house dust by guanine quantification.

The development of a quick color reaction for guanine in house dust has made it possible to screen many homes for mite products of allergenic consequence. The azo dye methods are specific enough to be useful for the development of a sanitary standard. Comparing the guanine quantification results with mite counts and determinations of the mite antigen P1 (Der p I) leads to the conclusion that the provisional standard for mattress dust of 0.6 mg guanine/g dust can be extended to dust from floor coverings and padded furniture, at least in western Europe. Below this level, the sensitization risk to patients allergic to house dust mites seems to be minimal.

Animals↗
PubMed1990

Trombiculid mites (Acari: Trombiculidae) and Rickettsia tsutsugamushi isolated from wild rodents in a new endemic area of Japan.

Investigations of trombiculid mites and Rickettsia tsutsugamushi in wild rodents were made in southern Gifu Prefecture where patients infected with tsutsugamushi disease recently have been found. A total of 16,396 trombiculid mites, consisting of 10 species from three genera, was collected from 170 Apodemus speciosus in two locations. Kani-Sakahogi and Kuze. Leptotrombidium scutellare (Nagayo et al.) (44.0%) was most predominant, followed by L. pallidum (Nagayo et al.) (26.9%); L. fuji (Kuwata et al.) (13.6%); and Gahrliepia saduski Womersley (14.2%). These four species constituted the bulk of the chigger mite fauna. L. scutellare was present from October to February with a remarkably high peak in November, whereas pallidum occurred from November to March with the highest peak in December. L. fuji and G. saduski showed their highest peaks in December and moderate peaks in early summer (April and May). Positive identification of Rickettsia tsutsugamushi in wild rodents from Kani-Sakahogi were found to be 50 and 58.3% in November 1985 and 1986, respectively, and 38.5% in November 1986 from Kuze. R. tsutsugamushi was isolated from chigger mites of an L. pallidum-rich group, displaying the highest titer to Karp strain. Serological investigation of rodents to R. tsutsugamushi antibodies were calculated as 41.6 and 50% positive in November 1985 and 1986 in Kani-Sakahogi, respectively, and 50% in November 1986 in Kuze. The Karp strain was dominant in specificity to antibodies. These results indicate that the surveyed areas have a high probability of occurrence of tsutsugamushi disease, and L. scutellare and L. pallidum may serve as the vectors in these areas. Particularly, we suggest that L. scutellare is the most important vector which has caused a recent outbreak of this disease in southern Gifu Prefecture.

Animals↗
PubMed1992

Efficient laboratory maintenance of blood-feeding mesostigmatid mites (Acari).

A technique is described for colonizing hematophagous mesostigmatid (= gamasid) mites under laboratory conditions. The apparatus consisted of a 473-ml (1 pint) Mason jar with sterilized surgical gauze and corrugated card placed inside on the bottom; these functioned as absorbent and mite bedding materials, respectively. A suckling mouse was placed onto the surgical gauze for 2-24 h to provide a food source for the mites. Stickem adhesive was smeared along the inside neck of the jar, which had a tight-fitting but ventilated screw-cap lid. The apparatus rested in a petri dish filled with water. This system provided excellent containment of the mites.

Animals↗
PubMed2004

Complete sequence of a picorna-like virus of the genus Iflavirus replicating in the mite Varroa destructor.

Aggregations of 27 nm virus-like particles were observed in electron microscopy images of sectioned Varroa destructor mite tissue. The scattered occurrence of individual particles and accumulation of the virions in lattices in the cytoplasm gave an apparent indication that the virus replicates in the mite. Sequence analysis of the RNA of the purified virus revealed a genome organization with high similarity to that of members of the genus Iflavirus. Phylogenetic analysis of the polymerase showed that the virus was related most closely to Deformed wing virus (DWV) and Kakugo virus (KV) of bees. The virus has a genome of 10 112 nt without the poly(A) tail, with an overall RNA genome identity of 84 % to those of DWV and KV and has one large ORF, translated into a 2893 aa polyprotein with an amino acid identity of 95 % to those of DWV and KV. The first 1455 nt of the ORF encoding the lower molecular mass structural proteins shows the greatest diversion from those of DWV and KV, with an RNA identity of 79 %, and translates to a polypeptide of 485 aa with an identity of 90 %. The name proposed for this virus is Varroa destructor virus 1 (VDV-1). To determine whether VDV-1 replicates in mites, a selective RT-PCR was done to detect the presence of the negative-sense RNA strand. The virus isolate and the closely related DWV could be discriminated by two primer sets, each specific to one virus. Both viruses replicated in the population of the mite species studied.

Amino Acid Sequence↗
PubMed1977

House dust mites in Iran.

In the Caspian Sea region of Iran asthma seems closely related to house dust allergy. Since a high proportion of house dust sensitive patients appear to be sensitive to house dust mites, an investigation was carried out to determine the occurrence, distribution and abundance of these species in Iranian house dust in order to assess their role and clinical importance in house dust allergy in Iran. Thirty-five samples of house dust collected from houses in the Caspian Sea region and five samples from other areas were examined for mites. The three pyroglyphid species Dermatophagoides pteronyssinus, D. farinae and Euroglyphus maynei, reported by European and Japanses workers to be common in house dust and to be a major source of house dust allergens, were found to occur in Iranian house dust and to account for nearly two-thirds of the total mit population present in the dust. Dermatophagoidex pteronyssinus was the most frequent and most numerous species recorded, occurring in 90% of the samples examined and forming 94% of the pyroglyphid and 60% of the total mite population. The frequency with which house dust mites were found in the Iranian Caspian Sea region coupled with the relatively high frequency of allergic bronchial asthma in this area suggests that they may well be an important precipitating factor in asthma in Iran.

Animals↗
PubMed1980

The allergenic importance of house dust and storage mites in asthmatics in Brunei, S.E. Asia.

Examination of dust from sleeping areas showed that storage mites, especially Glycyphagid species, were predominant in Brunei house dust. On skin testing sixty asthmatics with 1% extracts of six mite species, Dermatophagoides pteronyssinus was found to provoke the greatest number of positive skin reactions (66.7%), but positive reactions for Tyrophagus putrescentiae (50%), Acarus siro (35%), Glycyphagus domesticus (40%), and Lepidoglyphus destructor (45%) demonstrated that storage mites are also significant allergens. The role of storage mites in the causation of asthma in the tropics may have been underestimated.

Adolescent↗