Dog Allergens Research Articles

Concentration and determinants of molds and allergens in indoor air and house dust of French dwellings

Molds and allergens are common indoor biocontaminants. The aims of this study were to assess the concentrations of common molds in indoor air and floor dust and the concentrations of house dust mite, cat and dog allergens in mattress dust in French dwellings, and to assess predictors of these concentrations. A sample of 150 houses in Brittany (western France) was investigated. Airborne Cladosporium and Penicillium were detected in more than 90% of the dwellings, Aspergillus in 46% and Alternaria in only 6% of the housings. Regarding floor dust samples, Cladosporium and Penicillium were detected in 92 and 80% of the housings respectively, Aspergillus in 49% and Alternaria in 14%. House dust mite allergens Der p1 and Der f1 were detected in 90% and 77% of the mattress dust samples respectively and Can f1 and Fel d1 in 37% and 89% of the homes. Airborne and dustborne mold concentrations, although not statistically correlated (except for Aspergillus) shared most of their predictors. Multivariate linear models for mold levels, explaining up to 62% of the variability, showed an influence of the season, of the age of the dwelling, of aeration habits, presence of pets, smoking, signals of dampness, temperature and relative humidity. Allergens in the dust of the mattress were strongly related to the presence of pets and cleaning practices of bedsheets, these factors accounting for 60% of the variability. This study highlights ubiquitous contamination by molds and underlines complex interaction between outdoor and indoor sources and factors.

Sick Building Syndrome Among Junior High School Students in Japan in Relation to the Home and School Environment.

Purpose:There is an increasing concern about sick building syndrome (SBS), especially in Asia. The aim of this study is to investigate associations between SBS and the home, school environment and personal factors among Japanese junior high school students.Methods:We investigated students in four junior high schools in Hyogo in Kansai area, Japan. A questionnaire study was performed among students (n=1056), 12-15 years old. Temperature and relative air humidity was measured in the classrooms and dust was collected from the classroom floors and air and was analysed for cat and dog allergens. Associations were analysed by multi-level logistic regression.Results:Mucosal symptoms (45.4%), general symptoms (38.9%) and skin symptoms (22.6%) were common. Totally 8.8% reported cat allergy, 6.1% dog allergy, 6.0% mold allergy and 25.7% pollen allergy. Atopy, window pane condensation, floor dampness and odor at home and high relative air humidity in the classrooms were associated with SBS.Conclusion:The prevalence of SBS symptoms was high and associated with both home and school environment. Window pane condensation and floor dampness at home can increase the risk for SBS symptoms in students. Moreover high relative air humidity at school may increase the risk for SBS.

Oclacitinib in feline nonflea-, nonfood-induced hypersensitivity dermatitis: results of a small prospective pilot study of client-owned cats.

Oclacitinib is a Janus kinase inhibitor that decreases pruritus and lesions in allergic dogs. In cats, it is able to inhibit interleukin-31-induced pruritus; no information is available on its clinical effectiveness. To evaluate the efficacy, ease of administration and tolerability of oclacitinib in feline nonflea-, nonfood-induced hypersensitivity dermatitis. Cats >12 months of age and >3 kg body weight with a diagnosis of nonflea-, nonfood-induced hypersensitivity dermatitis were treated with oclacitinib, 0.4-0.6 mg/kg orally (p.o.) twice daily for 2 weeks, then once daily for an additional 14 days. Clinical lesions were evaluated with the Scoring Feline Allergic Dermatitis (SCORFAD) system and pruritus was evaluated with a 10-cm-long visual analog scale (VAS) before and at the end of the study. Owners assessed global efficacy, ease of administration and tolerability with a four-point scale. Twelve cats were treated with a mean initial oclacitinib dose of 0.47 mg/kg p.o. twice daily. There was good improvement in SCORFAD and VAS pruritus scores in five of 12 cases, while the other cats were unchanged, deteriorated or dropped out due to treatment failure. Owners scored global efficacy as good/excellent in four of 12 cases and ease of administration and tolerability as good/excellent in 10 of 12. Oclacitinib at 0.4-0.6 mg/kg p.o. may be an effective and safe drug for some cats with nonflea-, nonfood-induced hypersensitivity dermatitis. Further studies are needed to identify the most effective dose range for this species.

Decreased FEV1 % in asthmatic adults in Scottish homes with high Environmental Relative Moldiness Index values.

SummaryBackgroundExposures to indoor biological contaminants have been implicated in asthma's aetiology but their effect on lung function is not well quantified.ObjectiveThe aim of this cross‐sectional study of non‐smoking, asthmatic adults in Scotland was to determine the correlation between the results from a standard spirometry test, forced expiratory volume in one‐second percent (FEV 1%), and quantitative estimates of some biological exposures.MethodsA population (n = 55) of non‐smoking, adult asthmatics in Scotland was included in this study and each completed a questionnaire that allowed the determination of the Asthma Control Questionnaire scores (ACQ) and St. George's Respiratory Questionnaire scores (SGRQ), as well as corticosteroid use. Spirometry testing was completed and the pre‐bronchodilator FEV 1% value calculated. At about the same time, floor dust samples were collected in the living room and in the bedroom. These dust samples were analysed for mould contamination, as described by the Environmental Relative Moldiness Index (ERMI) values and by (1, 3)‐β‐D‐glucan concentrations, for endotoxin, and for dust mite, cat, and dog allergen concentrations. The asthmatics' FEV 1% values were tested for correlation (Pearson) to questionnaire‐based estimates of health. Also, each biological exposure was tested for correlation (Pearson) to the FEV 1% values.Results FEV 1% results were correlated with ACQ scores (ρ −0.586, P < 0.001), SGRQ scores (ρ −0.313, P = 0.020), and weakly with corticosteroid use (ρ −0.221, P = 0.105). The ERMI values in the homes (average 5.3) were significantly correlated with FEV 1% values (ρ −0.378, P = 0.004). There was no correlation between FEV 1% and concentrations of endotoxin, (1, 3)‐β‐D‐glucan, or any of the allergens.Conclusion and clinical relevanceAlthough these results do not prove that mould exposures caused the deficit in lung function observed in this study, it might be advisable for asthmatics to avoid high ERMI environments.

Characterization of human memory CD4+ T-cell responses to the dog allergen Can f 4

The recently identified dog lipocalin allergen Can f 4 is an important respiratory allergen. We sought to comprehensively characterize the memory CD4(+) T-cell responses of allergic and nonallergic subjects to Can f 4. Can f 4-specific CD4(+)CD45RO(+) T-cell lines (TCLs) from allergic and healthy subjects were established and characterized by their functional and phenotypic properties. The epitope specificity of the TCLs was tested with 48 overlapping 16-mer peptides spanning the sequence of Can f 4. HLA restriction of the specific TCLs and the binding capacity of the epitope-containing peptides to common HLA class II molecules were studied. Can f 4-specific memory CD4(+) TCLs were obtained at an 8-fold higher frequency from allergic than from nonallergic subjects. Functionally, the TCLs of allergic subjects exhibited a higher T-cell receptor avidity and expression of CD25 and predominantly produced IL-4 and IL-5. The TCLs of nonallergic subjects mostly secreted IFN-γ and IL-10, with high CXCR3 expression. Several distinct T-cell epitope regions along the allergen were identified. Importantly, the peptides from the region between amino acids 43 and 67 showed promiscuous HLA-binding capacity and induced memory CD4(+) T-cell responses in 90% of the allergic donors. Productive TH2-deviated memory T-cell responses to Can f 4 are observed in allergic but not nonallergic subjects. A 19-mer peptide sequence covering the core of the immunodominant region of the allergen is a potential target for the development of peptide-based allergen immunotherapy.

Indoor determinants of dustborne allergens in Mexican homes.

Exposure to indoor allergens represents a significant risk factor for allergies and asthma in several parts of the world. In Mexico, few studies have evaluated indoor allergens, including cat, dog, and mouse allergens and the factors that predict their presence. This study evaluates the main environmental and household predictors of high prenatal allergen levels and multiple allergen exposures in a birth cohort from Mexico City. A cross-sectional study was conducted as part of a birth cohort study of 1094 infants recruited during pregnancy and followed until delivery. We collected dust samples in a subset of 264 homes and assessed environmental factors. Der p 1, Der f 1, dust mite group 2, Fel d 1, Can f 1, Rat n 1, Mus m 1, and Bla g 2 concentrations in dust samples were measured using immunoassays. To define detectable allergen levels, the lowest limits of detection for each allergen were taken as cutoff points. Overall allergen exposure was considered high when four or more allergens exceeded detectable levels in the same household. Logistic regression was used for predictive models. Eighty-five percent of homes had at least one allergen in dust over the detection limit, 52.1% had high exposure (four or more allergens above detectable limits), and 11.7% of homes had detectable levels for more than eight allergens. Der p 1, Der p 2, Mus m 1, and Fel d 1 were the most frequent allergens detected. Each allergen had both common and distinct predictors. The main predictors of a high multiple allergen index were the size of the home, pesticide use, mother's age, mother as homemaker, and season. Increased indoor environmental allergen exposure is mainly related to sociodemographic factors and household cleaning.

Development of ELISA Assays for Measurement of Can f 1 and Can f 3 in Dog Allergen Extracts

RationaleDog allergen extract is a non-standardized extract with no potency measures. Understanding dog allergen extract potency will enhance the safety and efficacy of this product. Our goal is to develop monoclonal antibody-based sandwich ELISA assays for the measurement of Can f 1 and Can f 3.MethodsMouse monoclonal antibodies were generated against natural Can f 1 and dog serum albumin (Can f 3). Anti-Can f 1 and anti-Can f 3 hybridoma supernatants were screened against dog hair and dog epithelium extracts. Purified IgG antibodies were biotinylated for further pairwise screening and optimization. The defined concentrations of capture (non-biotinylated) and primary (biotinylated) antibodies were used for initial testing of various commercially available dog allergen extracts.ResultsScreening of Can f 1 antibodies revealed consistent strong responses with natural protein and dog extracts during indirect ELISA. Three pairs were selected for Can f 1 measurement: 6G1 as a capture antibody (2.5 μg/mL) and 4C3, 7D12, or 9A9 as biotinylated primary antibody (each at 1.0 μg/mL). Anti Can f 3 antibodies exhibit greater variability and less affinity: 10-20 μg/mL of each capture and primary antibody are required for consistent measurement of Can f 3. Further studies are needed to optimize both the assays.ConclusionssELISA assays have been developed for determining Can f 1 and Can f 3 contents of non-standardized dog allergen extracts. RationaleDog allergen extract is a non-standardized extract with no potency measures. Understanding dog allergen extract potency will enhance the safety and efficacy of this product. Our goal is to develop monoclonal antibody-based sandwich ELISA assays for the measurement of Can f 1 and Can f 3. Dog allergen extract is a non-standardized extract with no potency measures. Understanding dog allergen extract potency will enhance the safety and efficacy of this product. Our goal is to develop monoclonal antibody-based sandwich ELISA assays for the measurement of Can f 1 and Can f 3. MethodsMouse monoclonal antibodies were generated against natural Can f 1 and dog serum albumin (Can f 3). Anti-Can f 1 and anti-Can f 3 hybridoma supernatants were screened against dog hair and dog epithelium extracts. Purified IgG antibodies were biotinylated for further pairwise screening and optimization. The defined concentrations of capture (non-biotinylated) and primary (biotinylated) antibodies were used for initial testing of various commercially available dog allergen extracts. Mouse monoclonal antibodies were generated against natural Can f 1 and dog serum albumin (Can f 3). Anti-Can f 1 and anti-Can f 3 hybridoma supernatants were screened against dog hair and dog epithelium extracts. Purified IgG antibodies were biotinylated for further pairwise screening and optimization. The defined concentrations of capture (non-biotinylated) and primary (biotinylated) antibodies were used for initial testing of various commercially available dog allergen extracts. ResultsScreening of Can f 1 antibodies revealed consistent strong responses with natural protein and dog extracts during indirect ELISA. Three pairs were selected for Can f 1 measurement: 6G1 as a capture antibody (2.5 μg/mL) and 4C3, 7D12, or 9A9 as biotinylated primary antibody (each at 1.0 μg/mL). Anti Can f 3 antibodies exhibit greater variability and less affinity: 10-20 μg/mL of each capture and primary antibody are required for consistent measurement of Can f 3. Further studies are needed to optimize both the assays. Screening of Can f 1 antibodies revealed consistent strong responses with natural protein and dog extracts during indirect ELISA. Three pairs were selected for Can f 1 measurement: 6G1 as a capture antibody (2.5 μg/mL) and 4C3, 7D12, or 9A9 as biotinylated primary antibody (each at 1.0 μg/mL). Anti Can f 3 antibodies exhibit greater variability and less affinity: 10-20 μg/mL of each capture and primary antibody are required for consistent measurement of Can f 3. Further studies are needed to optimize both the assays. ConclusionssELISA assays have been developed for determining Can f 1 and Can f 3 contents of non-standardized dog allergen extracts. sELISA assays have been developed for determining Can f 1 and Can f 3 contents of non-standardized dog allergen extracts.

The Evaluation of Efficacy and Adverse Effect in Intralymphatic Allergen-Specific Immunotherapy Against House Dust Mite, Cat, and Dog Allergens in Allergic Rhinitis

The Evaluation of Efficacy and Adverse Effect in Intralymphatic Allergen-Specific Immunotherapy Against House Dust Mite, Cat, and Dog Allergens in Allergic Rhinitis

House-dust mite allergy: mapping of Dermatophagoides pteronyssinus allergens for dogs by two-dimensional immunoblotting.

IntroductionSpecific immunotherapy has shown to be very useful for allergy control in dogs, with a common success rate ranging from 65% to 70%. However, this efficacy could probably be improved and the identification of individual allergomes, with the choice of more adequate molecular allergen pools for specific immunotherapy, being the strategy.AimTo map Dermatophagoides pteronyssinus (Der p) allergens for mite-sensitized atopic dogs, for better understanding how individual allergograms may influence the response to house-dust mite immunotherapy.Material and methodsTo identify the Der p mite allergome for dogs, 20 individuals allergic to dust-mites and sensitized to Der p, were selected. The extract from Der p was submitted to isoelectric focusing (IEF), one-dimensional (1-D) and two-dimensional (2-D) sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Separated proteins were blotted onto polyvinylidene difluoride (PVDF) membranes and immunoblottings were performed with patient sera. Allergen-bound specific IgE was detected.ResultsEleven allergens were identified from isoelectric focusing (IEF), as well as from 1-D SDS PAGE. From 2-D SDS-PAGE, 24 spots were identified.ConclusionsSeveral similarities were found between dog and human allergograms and no absolute correlation between sensitization and allergy was observed either. As in humans, different individual allergograms do not seem to implicate different clinical patterns, but may influence the response to specific immunotherapy. The molecular epidemiology approach in veterinary allergy management, by the characterization of individual patients’ allergoms and by choosing the best molecular allergen pool for each patient could also improve the efficacy of allergy immunotherapy.

IgE Reactivity of the Dog Lipocalin Allergen Can f 4 and the Development of a Sandwich ELISA for Its Quantification.

PurposeDivergent results on the IgE reactivity of dog-allergic subjects to Can f 4 have been reported. The aim of this study was to evaluate the significance of Can f 4 in dog allergy and to develop an immunochemical method for measuring Can f 4 content in environmental samples.MethodsWe purified the natural dog allergen Can f 4 from a dog dander extract by monoclonal antibody-based affinity chromatography and generated its variant in a recombinant form. Sixty-three dog-allergic patients and 12 nonallergic control subjects were recruited in the study. The IgE-binding capacity of natural Can f 4 and its recombinant variant was assessed by ELISA, immunoblotting, and skin prick tests (SPT).ResultsEighty-one percent of the dog-allergic patients showed a positive result to the immunoaffinity-purified natural Can f 4 in IgE ELISA, but only 46% in IgE immunoblotting. Respective results with the recombinant Can f 4 variant were 54% and 49%. SPT results reflected those obtained in ELISA and immunoblotting. The overall IgE reactivity of the immunoaffinity-purified natural Can f 4 was found to depend strongly on the integrity of the allergen's conformation. A sandwich ELISA based on monoclonal antibodies was found to be functional for measuring Can f 4 in environmental samples.ConclusionsCan f 4 is a major allergen of dog together with Can f 1 and Can f 5. In combination with other dog allergens, it improves the reliability of allergy tests in dog allergy.

Differential effects of age and intestinal helminthiasis on positivity rate of skin prick reaction to environmental allergens among Nigerians

Background: Skin prick testing (SPT) conventionally used to investigate immediate type (type 1) hypersensitivity to allergens is reported to be affected by varying factors. It is hypothesized by present study that immunomodulation of T-cell by parasitic helminthic infection may affect skin prick reaction.Study Objectives: The primary objective of this cross-sectional study is to determine the prevalence of intestinal helminthiasis and its effect on the outcome of SPT to environmental allergens.Participants, Materials and Methods: Skin prick test was performed on 296 residents (113 adults and 183 children) rural and urban parts of Ibadan, South-West Nigeria. Stool specimen was also collected and examined for ova, cyst and larvae of intestinal worms.Results and Conclusion: The prevalence of intestinal helminthiasis was 20.8% and 21.2% in children and adults respectively. Prevalence of intestinal helminthiasis in adults from rural settings was significantly higher when compared with adults from urban settings. Significantly higher positive skin test to dog allergen was observed in helminth infected participants when compared to uninfected participants. Furthermore, significantly higher positive skin test to cockroach, mite, mold, and mouse allergen was observed in adults when compared to children. This suggests that the intestinal helminthiasis is found among all age groups in this region, but do not affect skin reaction to environmental allergens as much as ages of participants.

Prevalence of and risk factors for increased serum levels of allergen-specific IgE in a population of Norwegian dogs.

BackgroundThe importance of different allergens in association with IgE production and canine atopic dermatitis (CAD) has been poorly studied and few studies exist on factors influencing allergen-specific IgE antibodies in serum. The aim of this cross-sectional study was to investigate the prevalence of elevated IgE levels to different environmental allergens in Norwegian dogs with a suspicion of CAD. The secondary aim was to identify risk factors associated with elevated serum levels of allergen-specific IgE.ResultsThe study sample consisted of serum from 1313 dogs of 161 different breeds. All samples were submitted for serologic IgE-testing (Fc epsilon R1 alpha-based ELISA) based on suspicion of CAD. Overall, 84.3% of the dogs had elevated IgE levels to one or more of the allergen(s). The predominant allergens amongst the positive results were the indoor allergens (Acarus siro 84.0%, Dermatophagoides farinae 80.2%, Tyrophagus putrescentiae 79.9%). Sheep sorrel was the most commonly encountered outdoor allergen (40.0%). Only 2.6% of the dogs with elevated IgE levels were positive to flea saliva.The test results varied significantly depending on when the serum samples were taken. Samples taken during summer and autumn more often came out positive than samples taken during winter and spring. Geographical variations were also demonstrated. A greater proportion of females than males had positive test results, and more females than males tested positive to outdoor allergens. The mean age was significantly higher in the dogs testing positive than amongst the dogs testing negative. The allergen-specific IgE levels varied with breed. The boxer was the only breed with a significantly higher proportion of positive test results compared to the other breeds. Boxers also had a higher prevalence of elevated IgE levels to outdoor allergens, whereas the Rottweiler had a higher prevalence of elevated IgE levels to indoor allergens compared to the other breeds.ConclusionsIgE hypersensitivity was most often associated with indoor allergens. Outdoor allergens were of minor importance and IgE reactivity to flea saliva was rare. Breed differences in allergen-specific IgE levels were identified. Season of sampling, and the dogs’ geographical localisation, sex and age also affected the results of the IgE analysis.

Cat, Dog and House Dust Mite Allergen Levels on Children’s Soft Toys

FF Wu, MW Wu, MH Ting, J Crane, R Siebers. J Asthma. 2014;51(1):75–78 Children's soft toys are known to harbor house dust mite (HDM) allergens, but little is known about whether they harbor cat or dog allergens. The objective of the study was to measure cat (Fel d 1), dog (Can f 1), and HDM allergens on children's soft toys. Children’s soft toys and mattresses were analyzed. Dust was collected from 40 children's soft toys and their mattresses, and data were gathered on pet ownership. Dust samples were analyzed for Fel d …

Mouse allergen is the major allergen of public health relevance in Baltimore city.

SK Ahluwalia, RD Peng, PN Breysse. J Allergy Clin Immunol. 2013;132(4):830–835.e1–e2 The goal of this study was to evaluate relationships between exposure to mouse and other perennial allergens and clinical markers of asthma. A total of 150 Baltimore children (ages 5–17 years) with persistent asthma were followed up for 1 year. Allergy skin testing was performed to dust mites, mouse, cockroach, cat, dog, and other perennial allergens. Serum-specific IgE levels to those allergens were also measured. Sensitization was defined as a skin test wheal ≥3 mm in diameter more than the negative control subjects. Spirometry with bronchodilator reversibility (≥12% reversibility in forced expiratory volume in 1 second [FEV1] after 2 puffs of …

ELISA testing for soy antigens in dry dog foods used in dietary elimination trials.

The use of elimination diet trials is necessary in the diagnosis of food allergies and intolerances. The objective of this study was to determine in vitro if four over-the-counter (OTC) dry dog foods carrying a "no soy" claim and seven veterinary therapeutic dry dog foods designed for food elimination trials were suitable for a soybean elimination trial. A 100 g sample of each diet plus one soy positive and one soy negative control diet were submitted for enzyme-linked immunosorbent assay testing to an independent food laboratory. The positive control diet contained >25 ppm soy protein antigens and the negative control contained <2.5 ppm. Three of the four OTC "no soy" claiming diets were positive for soy antigen. Two of the three soy-containing diets had >25 ppm. Three veterinary therapeutic diets had less than the lowest detectable limit of soy protein and four were positive (>2.5 ppm). OTC dog food diets that claim to contain "no soy" may contain high concentrations of soy protein and, therefore, should not be used in soy elimination trials in suspect food allergic dogs. The veterinary therapeutic diet selected for a soy elimination trial needs to be carefully chosen based on diet history.

Designing a multimer allergen for diagnosis and immunotherapy of dog allergic patients.

BackgroundDog dander extract used for diagnosis and allergen-specific immunotherapy is often of variable and of poor quality.ObjectiveTo assemble four well-established dog allergen components into one recombinant folded protein for improved diagnosis and vaccination of allergy to dog.MethodsA linked molecule, comprising the four dog lipocalin allergens Can f 1, Can f 2, Can f 4 and Can f 6 was constructed. The tetrameric protein was structurally characterized by small angle X-ray scattering, and compared with each single recombinant lipocalin allergen or an equimolar mix of the four allergens by analytical size exclusion chromatography, circular dichroism, allergen-specific IgE in serum by ELISA and allergen-dependent capacity to activate basophils. The immunogenicity of the fusion protein was evaluated in immunized mice by assessing splenocyte proliferation and antibody production.ResultsThe linked tetrameric construct was produced as a soluble fusion protein, with the specific folds of the four individual allergens conserved. This multi-allergen molecule was significantly more efficient (p<0.001) than each single recombinant allergen in binding to dog-specific IgE, and the epitope spectrum was unaffected compared to an equimolar mix of the four allergens. Basophil degranulation revealed that the biologic activity of the linked molecule was retained. Immunization of mice with the linked construct induced comparable allergen-specific IgG responses with blocking capacity towards all included allergens and generated comparably low T-cell responses.ConclusionWe provide the first evidence for a linked recombinant molecule covering the major dog allergens for potential use in diagnostics and allergy vaccination of dog allergic patients.

Indoor pollutant exposure is associated with heightened respiratory symptoms in atopic compared to non-atopic individuals with COPD.

BackgroundIndoor particulate matter (PM) has been linked to respiratory symptoms in former smokers with COPD. While subjects with COPD and atopy have also been shown to have more frequent respiratory symptoms, whether they exhibit increased susceptibility to PM as compared to their non-atopic counterparts remains unclear. The aim of this study was to determine whether atopic individuals with COPD have greater susceptibility to PM compared to non-atopic individuals with COPD.MethodsFormer smokers with moderate to severe COPD were enrolled (n = 77). PM2.5, PM with diameter <2.5 micrometers, was measured in the main living area over three one-week monitoring periods at baseline, 3, and 6 months. Quality of life, respiratory symptoms and medication use were assessed by questionnaires. Serum was analyzed for specific IgE for mouse, cockroach, cat, dog and dust mite allergens. Atopy was established if at least one test was positive. Interaction terms between PM and atopy were tested and generalized estimating equation analysis determined the effect of PM concentrations on health outcomes. Multivariate models were adjusted for age, sex, education, race, season, and baseline lung function and stratified by atopic status.ResultsAmong atopic individuals, each 10 μg/m3 increase in PM was associated with higher risk of nocturnal symptoms (OR, 1.95; P = 0.02), frequent wheezing (OR, 2.49; P = 0.02), increased rescue medication use (β = 0.14; P = 0.02), dyspnea (β = 0.23; P < 0.001), higher St. George’s Respiratory Quality of Life score (β = 2.55; P = 0.01), and higher breathlessness, cough, and sputum score (BCSS) (β = 0.44; P = 0.01). There was no association between PM and health outcomes among the non-atopic individuals. Interaction terms between PM2.5 and atopy were statistically significant for nocturnal symptoms, frequency of rescue medication use, and BCSS (all P < 0.1).ConclusionsIndividuals with COPD and atopy appear to be at higher risk of adverse respiratory health effects of PM exposure compared to non-atopic individuals with COPD.

Effect of deployment time on endotoxin and allergen exposure assessment using electrostatic dust collectors.

The electrostatic dust collector (EDC) is a passive dust sampling device for exposure assessment of airborne endotoxin and possibly allergens. EDCs consist of a non-conducting plastic folder holding two or four electrostatic cloths of defined area. The sampling time needed to achieve detectable and reproducible loading for bioaerosols has not been systematically evaluated. Thus, in 15 Iowa farm homes EDCs were deployed for 7-, 14-, and 28-day sampling periods to determine if endotoxin and allergens could be quantified and if loading rates were uniform over time, i.e. if loads doubled from 7 to 14 days or 14 to 28 days and quadrupled from 7 to 28 days. Loadings between left and right paired EDC cloths were not significantly different and were highly correlated for endotoxin, total protein, and cat (Fel d1), dog (Can f1), and mouse (Mus m1) allergens (P < 0.001). EDCs performed especially well for endotoxin sampling with close agreement between paired samples (Pearson r = 0.96, P < 0.001). Endotoxin loading of the EDCs doubled from 7- to 14-day deployments as hypothesized although the loading rate decreased from 14 to 28 days of sampling with only a 1.38-fold increase. Allergen exposure assessment using EDCs was overall less satisfactory. Although there was reasonable agreement between paired samples, only exposures to cat, dog, and mouse allergens were reliable and these only at the longer deployment times.

Human CD4+ T cell responses to the dog major allergen Can f 1 and its human homologue tear lipocalin resemble each other.

Lipocalin allergens form a notable group of proteins, as they contain most of the significant respiratory allergens from mammals. The basis for the allergenic capacity of allergens in the lipocalin family, that is, the development of T-helper type 2 immunity against them, is still unresolved. As immunogenicity has been proposed to be a decisive feature of allergens, the purpose of this work was to examine human CD4+ T cell responses to the major dog allergen Can f 1 and to compare them with those to its human homologue, tear lipocalin (TL). For this, specific T cell lines were induced in vitro from the peripheral blood mononuclear cells of Can f 1-allergic and healthy dog dust-exposed subjects with peptides containing the immunodominant T cell epitopes of Can f 1 and the corresponding TL peptides. We found that the frequency of Can f 1 and TL-specific T cells in both subject groups was low and close to each other, the difference being about two-fold. Importantly, we found that the proliferative responses of both Can f 1 and TL-specific T cell lines from allergic subjects were stronger than those from healthy subjects, but that the strength of the responses within the subject groups did not differ between these two antigens. Moreover, the phenotype of the Can f 1 and TL-specific T cell lines, determined by cytokine production and expression of cell surface markers, resembled each other. The HLA system appeared to have a minimal role in explaining the allergenicity of Can f 1, as the allergic and healthy subjects' HLA background did not differ, and HLA binding was very similar between Can f 1 and TL peptides. Along with existing data on lipocalin allergens, we conclude that strong antigenicity is not decisive for the allergenicity of Can f 1.

Structural aspects of dog allergies: The crystal structure of a dog dander allergen Can f 4

Four out of six officially recognized dog allergens are members of the lipocalin protein family. So far, a three-dimensional structure has been determined for only one dog allergen, Can f 2, which is a lipocalin protein. We present here the crystal structure of a second lipocalin allergen from dog, a variant of Can f 4. Moreover, we have compared and analyzed the structures of these two weakly homologous (amino acid identity 21%) dog allergens. The size and the amino acid composition of the ligand-binding pocket indicate that Can f 4 is capable of binding only relatively small hydrophobic molecules which are different from those that Can f 2 is able to bind. The crystal structure of Can f 4 contained both monomeric and dimeric forms of the allergen, suggesting that Can f 4 is able to form transient (weak) dimers. The existence of transient dimers in solution was confirmed by use of native mass spectrometry. The dimeric structure of Can f 4 is formed when the ends of four β-strands are packed against the same strands from the second monomer. The residues in the interface are mainly hydrophobic and the formation of the dimer is similar to the major horse allergen Equ c 1. Interestingly, the crystal structure of dog Can f 2 has been reported to show a different type of dimer formation. The capability of these allergens to form dimers may be important for the development of immediate allergic reaction (mast cell activation) because oligomeric allergens can effectively present multivalent epitopes.