A comparison of airborne and dust-borne allergens and toxins collected from home,office and outdoor environments both in New Haven,United States and Nanjing,China

In this study, the airborne and dust-borne concentrations of endotoxin, (1,3)-β-d-glucan and five house dust allergens were measured in office, home, and outdoor environments both in New Haven, United States and Nanjing, China. Air samples were collected using a BioSampler at a flow rate of 12.5 l/min for 30 min. Dust samples were simultaneously collected using a surface sampler. Dust samples went through extraction and dilution before analysis, while air samples were analyzed directly. Limulus Amoebocyte Lysate (LAL) Pyrochrome and Glucatell assays were used to quantify endotoxin and (1,3)-β-d-glucan concentration levels, respectively. Enzyme-linked sorbent assay was used to measure the dust mites, cat, dog, and cockroach allergens. The experimental results indicated that endotoxin, (1,3)-β-d-glucan and allergen concentrations vary greatly both with samples and environments. In all tested environments, endotoxin concentration ranged from 0.8 to 83.7 ng/m³ for air, and 7.8 to 14.3 ng/mg for dust. (1,3)-β-d-glucan concentration ranged from 0.1 to 9.8 ng/m³ for air, and 6.6 to 110 ng/mg for dust. Cockroach allergens were detected only in New Haven office and outdoor environments, and other allergens ranged from 0.1 to 90 ng/mg for dust samples, and from 1.5 to 1,282 ng/m³ for air samples. In general, similar profiles of allergens and toxins were observed in New Haven and Nanjing environments. Linear regression analysis showed that there were better endotoxin and (1,3)-β-d-glucan linear correlations (R ² = 0.78, 0.87, respectively) between the dust and air samples compared to those of the allergens Der f 1 and Der p 1 (R ² = 0.5, 0.7, respectively). This research contributes to the development of robust biological exposure assessment and the elaboration of airborne and dust-borne bio-mass in the living environments.     

Crystal Structure of the Dog Lipocalin Allergen Can f 2: Implications for Cross-reactivity to the Cat Allergen Fel d 4

The dog lipocalin allergen Can f 2 is an important cause of allergic sensitization in humans worldwide. Here, the first crystal structure of recombinant rCan f 2 at 1.45 Å resolution displays a classical lipocalin fold with a conserved Gly-Xaa-Trp motif, in which Trp19 stabilizes the overall topology of the monomeric rCan f 2. Phe38 and Tyr84 localized on the L1 and L5 loops, respectively, control access to the highly hydrophobic calyx. Although the rCan f 2 calyx is nearly identical with the aero-allergens MUP1, Equ c 1 and A2U from mouse, horse and rat, respectively, no IgE cross-reactivity was found using sera from five mono-sensitized subjects. However, clear IgE cross-reactivity was demonstrated between Can f 2 and the cat allergen Fel d 4, although they share less than 22% sequence identity. This suggests a role for these allergens in co-sensitization between cat- and dog-allergic patients.     

Localisation of a carbohydrate epitope recognised by human IgE in pollen of Cupressaceae

The objectives of the present study were: (1) to localise, at the subcellular level, the allergens in pollen of Cupressaceae species, using a monoclonal antibody (mAb 5E6) that is specific for carbohydrate epitopes of allergenic components of Cupressus arizonica pollen extract; (2) to determine whether the glycidic epitope recognised by mAb 5E6 was present in pollen of allergenic species taxonomically unrelated to Cupressaceae; and (3) to determine whether human IgE purified from monosensitive patients recognises the same epitope as mAb 5E6 in Cupressaceae pollen. Immunogold labelling of mAb 5E6 showed a high density of gold particles on the orbicules, supporting the hypothesis that they are important vectors of allergens. A high density was also found on the exine and in the cytoplasm, with the latter finding confirming that fragments of pollen ruptured under humid conditions can represent a vector. The glycidic epitope recognised by mAb 5E6 was detected in all of the species taxonomically unrelated to Cupressaceae, although with varying density. Human IgE recognised the same epitope as mAb 5E6. These findings are consistent with observations of diffuse allergenic cross-reactivity among various allergens. The in situ localisation of a common epitope recognised by both a monoclonal antibody and human IgE could be of importance in immunotherapy.     

Characterization of oligosaccharides from an antigenic mannan of Saccharomyces cerevisiae

Mannans of the yeast Saccharomyces cerevisiae have been implicated as containing the allergens to which bakers and brewers are sensitive and also the antigen recognized by patients with Crohn's disease. A fraction of S. cerevisiae mannan, Sc500, having high affinity for antibodies in Crohn's patients has been characterized by NMR spectroscopy followed by fragmentation using alkaline elimination, partial acid hydrolysis and acetolysis. The released oligosaccharides were separated by gel filtration on a Biogel P4 column and analyzed by fluorescence labeling, HPLC and methylation analysis. The relationship between structure and antigen activity was measured by competitive ELISA. The antigenic activity of the original high molecular weight mannan could be ascribed to terminal Man13Man12 sequences which are rarely found in human glycoproteins but were over-represented in Sc500 compared to other yeast mannans.     

The aluminum content in some patch test allergens

The Al content of 18 patch test allergens were measured by electrothermal atomic absorption spectrophotometry. It was found that these preparations contained Al in various amounts. We conclude that the presence of Al in patch test allergens may interfere with the diagnosis and evaluations of patients to whom the test is applied.     

Thiophilic adsorption chromatography: purification of Equ c2 and Equ c3, two horse allergens from horse sweat

Purification of two allergens from horse (Equus caballus) sweat, Equ c2 and Equ c3, by means of salt-promoted chromatography on a “thiophilic” (T-gel) adsorbent is described. Immobilization of these proteins was found to be dependent on the presence of water-structure-forming salts where the ammonium sulphate concentration in the equilibration buffer was 2 M. Equ c2 showed higher affinity towards the thiophilic matrix than Equ c3. Their molecular mass (M_r) values established by SDS–polyacrylamide gel electrophoresis were for Equ c2 ≈17 000 and for Equ c3 ≈16 000, and both proteins showed a low isoelectric point of ≈3.8. Their allergenic properties were also investigated using sera from horse-sensitized patients, where it was demonstrated that these proteins exhibited an IgE antibody binding capacity. In this report we show the broad potential applications of thiophilic adsorption chromatography for the efficient purification of allergens.     

Analysis of liquid extracts from tree and grass pollens by capillary electromigration methods

Capillary electromigration methods, zone electrophoresis (CZE), micellar electrokinetic chromatography (CMEKC) and isotachophoresis (CITP), have been used for analysis of water and water-buffer extracts from tree-common birch (Betula verrucosa) and grass-orchardgrass (Dactylis glomerata) pollen samples. Water extracts were analyzed by CZE using acetic acid as background electrolyte (BGE), by CMEKC in tris-phosphate BGE with anionic detergent sodium dodecyl sulfate (SDS) micellar pseudophase (TP-SDS) and by CITP in cationic mode with leading/terminating cations K+/BALA+ (beta-alanine (BALA)) and in anionic mode with leading/terminating anions Cl-/MES- (2-(N-morpholino)ethanesulphonic acid (MES)). Moreover, acetic acid extracts were analyzed by CZE using acetic acid as BGE, and alkaline water-SDS-buffer extracts were analyzed by CMEKC using TP-SDS as BGE. Extracted amounts of pollen allergens and other UV-absorbing compounds and the number of resolved components were evaluated from CZE, CMEKC and CITP analyses of the liquid extracts. Larger amounts of UV-absorbing material were found in the water-buffer pollen extracts than in the water extracts. More UV-absorbing material was found in all extracts from D. glomerata pollen than in relevant extracts from B. verrucosa pollen. It was found by CITP that the extracted amounts of anionic components and their number were much higher than those of cationic components. Concentrations of some inorganic ions (e.g. Cl-, K+, Na+, Ca2+) in pollen samples were also determined by CITP.     

Betulaceae, Corylaceae, Cupressaceae, Fagaceae and Salicaceae around Parma (Northern Italy): Pollen calendars from 1995 to 1997

Many seasonal respiratory allergies are caused byairborne pollens. There is an evident correlationbetween allergic attacks and the amount of pollens inthe atmosphere at any time. The airbornetree pollen concentration and the relevantrepercussions on pollinotics hasnot yet been extensively reported for all Italian regions.We present the results of a 3-year, weekly, tree pollen count byBurkard spore trap from the atmosphere of Parma,Italy. Annual pollen calendars were made from theresults. The study has been conducted because, in Europe,an increasing frequency of allergic sensitisation to thesepollens has been observed.