Release behavior of small sized daughter allergens from Cryptomeria japonica pollen grains during urban rainfall event

In Japan, Cryptomeria japonica pollen (with diameter ~30 μm) is scattered during each spring season. Daughter allergenic particles, which are smaller in size than their parent pollen grain and are abundant in fine particles (the particle sizes < 1.1 μm, PM_1.1), are released in the atmosphere. The daughter allergenic particles of pollen can be transported in the urban atmosphere for a long period of time after their release. In particular, the daily variation delays in the peaks of allergenic Cry j 1 concentrations compared with the peaks of airborne parent pollen counts were observed in high levels during 1 or 2 sunny days after rainfall. In addition, long range transportation of Asian dusts (ADS) from the East Asian continent was also found during the pollen scattering seasons in Japan. Therefore, the interaction between pollen and air pollutants, including ADS, should be of concern. Thus, in this study, the morphological change of Cryptomeria japonica pollen and the elution behavior of its allergenic contents (Cry j 1) were investigated. Our results confirmed the existence of fine daughter allergen particles, which are clearly differ from the parent pollen grains in size. Fine allergenic particles in atmosphere were increased, while coarse allergenic particles were decreased on sunny days after rainfall. However, the correlation between the mass concentrations of fine particles and mass levels of Cry j 1 in coarse particles (the particle sizes > 7.0 μm) was poor. The possible reason may be pollen burst at high humidity before rainfall. Additionally, Cry j 1 contents were emitted from the so-called Ubisch body, which contains allergenic Cry j 1 abundantly when pollen was in contact with rainfall. In particular, we found that 60% of allergenic Cry j 1 contents released in air polluted rainfall contained Ca²⁺ ion derived from road dust and ADS. Therefore, rainfall should be a main factor to induce transition of pollen allergenic contents to fine particles. In conclusion, allergenic particles which are small sized and translated into fine particles by rainfall can be inhaled into the lower respiratory tract and contribute to the hypersensitivity of asthma.     

Size distribution of allergenic Cry j 2 released from airborne <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> pollen grains during the pollen scattering seasons

Japanese cedar (Cryptomeria japonica) pollinosis is one of seasonal allergic rhinitis that mainly occurs in Japan. The pollinosis is caused by two main kinds of allergenic proteins called Cry j 1 and Cry j 2 which exist in Cryptomeria japonica pollen. In our previous study, we reported that the size-segregated of airborne fine allergenic Cry j 1 and morphological change of Cry j 1 due to the contact with rainfall. However, the study on airborne allergenic Cry j 2 in different particle sizes has not been identified until now. Therefore, the main aim of this study is to investigate the size distribution and scattering behavior of allergenic Cry j 2. The Cry j 2 particles were collected and determined in different particle sizes at the urban sampling points during the most severe pollination season of 2012 in Saitama, Japan. After the size-segregated Cry j 2 allergenic particles were collected using an Andersen high-volume (AHV) atmospheric sample, the airborne Cry j 2 concentrations were determined with a surface plasmon resonance (SPR) method. At the same time, the airborne Cryptomeria japonica pollens were also counted by the Durham pollen sampler. The higher concentrations of the allergenic Cry j 2 were detected even in particle sizes equal to or less than 1.1 μm (PM_1.1) than other particle sizes. The airborne particles ranges from 0.06 to 11 μm were also collected by a low-pressure impactor (LPI) atmospheric sampler. After that, the concentrations of Cry j 2 allergenic particles in fine particle sizes were measured by the SPR method either. With the help of this study, we have confirmed the existence of fine daughter allergenic particles, which clearly differ from the parent pollen grains in size, especially after the rainy days. It is possible that the daughter allergenic species will be released from the fractions of cell wall and burst pollen grains. We concluded that rainwater was one of the important factors that affects the release of pollen allergenic proteins of both Cry j 1 and Cry j 2 from the parent pollen grains.     

Allergological aerobiology

Summary Aerobiology, in the strict sense, is the science which is studying the transportation of biological particles through the air. This process includes the release, the staying airborne, and deposition of particles of biological origin. Until recently, most of the allergological research has been done on the processes before and after the strict aerobiological pathway. The allergological studies were primarily dealing with the allergenic properties of the particles, irrespective of their aerobiological characteristics. Also, many studies have been done about the effects of allergens in sensitized people, after deposition in the respiratory organs. But for a more complete knowledge of the allergic process, allergological aerobiology in the strict sense is indispensable. The understanding of symptoms of respiratory allergy requires knowledge of the aerodynamic properties of airborne allergen carrying particles.     

New immunodiagnostic system

We have developed a new immunodiagnostic system whichmeasures personal allergen exposure and which can beused to identify allergens.Personal exposure is directly sampled using inertialimpaction filters which fit just inside the nose andcollect particles (mainly >5 µm) inhaled duringnormal respiration. These samplers provide both anindex of personal exposure as well as being aninexpensive and portable sampling system.The particles are captured on adhesive tapes which arethen laminated with a protein-binding membrane. Theallergens eluting from the particles are bound by the membrane in theperiphery of each particle. The systemthen uses either allergen-specific monoclonalantibodies or the subject's IgE as primary probes toimmuno-label the `halo' of allergen around individualallergen-containing particles. Such an assay is verysensitive and can detect a single particle carryingallergens. In addition, the system providesinformation on the size, shape and allergen content ofthe particles. Because the particles carryingallergens can be seen, high resolution video images ofpollen grains and fungal spores can be subjected to atraditional morphological study or a range of featureextraction routines. This information can be comparedto a database of some known allergenic pollen grainsand fungal spores which we have also assembled tofacilitate their identification.When using monoclonal antibodies as the probe, thesystem determines the amount of allergen the subjectis exposed to and the characteristics of the particles(size, shape, etc). When using the subject's IgE as theprobe, the system allows visualisation of the allergensources that an individual is allergic to. The systemmay have clinical applications in quantifying personalexposure as well as identifying allergens anddetermining exposure to unsuspected allergens.     

The use of discriminant analysis and neural networks to forecast the severity of the Poaceae pollen season in a region with a typical Mediterranean climate

Biological particles in the air such as pollen grains can cause environmental problems in the allergic population. Medical studies report that a prior knowledge of pollen season severity can be useful in the management of pollen-related diseases. The aim of this work was to forecast the severity of the Poaceae pollen season by using weather parameters prior to the pollen season. To carry out the study a historical database of 21 years of pollen and meteorological data was used. First, the years were grouped into classes by using cluster analysis. As a result of the grouping, the 21 years were divided into 3 classes according to their potential allergenic load. Pre-season meteorological variables were used, as well as a series of characteristics related to the pollen season. When considering pre-season meteorological variables, winter variables were separated from early spring variables due to the nature of the Mediterranean climate. Second, a neural network model as well as a discriminant linear analysis were built to forecast Poaceae pollen season severity, according to the three classes previously defined. The neural network yielded better results than linear models. In conclusion, neural network models could have a high applicability in the area of prevention, as the allergenic potential of a year can be determined with a high degree of reliability, based on a series of meteorological values accumulated prior to the pollen season.     

WebAllergen: a web server for predicting allergenic proteins

WebAllergen is a web server that predicts the potential allergenicity of proteins. The query protein will be compared against a set of prebuilt allergenic motifs that have been obtained from 664 known allergen proteins. The query will also be compared with known allergens that do not have detectable allergenic motifs. Moreover, users are allowed to upload their own allergens as alternative training sequences on which a new set of allergenic motifs will be built. The query sequences can also be compared with these motifs. AVAILABILITY: http://weballergen.bii.a-star.edu.sg/     

Polymorphism in allergens

Allergens are antigens that elicit an IgE-mediated immune response; they originate from diverse sources such as pollens, mites, molds, mammal exudates, insects and food. Allergenic molecules can contain several antigenic determinants, termed epitopes. Allergenic proteins have been discovered with polymorphisms, i.e., a mixture of similar molecules with minor variations in their amino acid sequences. These are called isoallergens or allergenic variants depending on the degree of similarity. Polymorphism may be defined by the presence of several alleles of the same gene or as families of related genes. Polymorphisms can have an important effect on the epitopes recognized by T lymphocytes, monoclonal antibodies and IgE of allergic patients. Individual polymorphisms can affect the basal level of allergenicity as well as the cross-reactivity with other allergens. The use of isoforms with low or total absence of IgE binding capacity but with high capacity to stimulate T cell response has been suggested as an alternative to the conventional immunotherapy for allergic diseases. Standardization of allergenic compounds can be affected by the differing proportions of isoforms in allergenic sources from different regions.     

Crystal structure analysis of NP24-I: a thaumatin-like protein

The crystal structure of NP24-I, an isoform of the thaumatin-like protein (TLP) NP24 from tomato, has been reported. A prominent acidic cleft is observed between domains I and II of the three-domain structure of this antifungal protein, a feature common to other antifungal TLPs. The defensive role of the TLPs has also been attributed to their beta-1,3-glucanase activity and here too the acidic cleft is reported to play a vital role. NP24 is known to bind beta-glucans and so a linear beta-1,3-glucan molecule has been docked in the interdomain cleft of NP24-I. From the docked complex it is observed that the beta-glucan chain is so positioned in the cleft that a Glu and Asp residue on either side of it may form a catalytic pair to cause the cleavage of a glycosidic bond. NP24 has been reported to be an allergenic protein and an allergenic motif could be identified on the surface of the helical domain II of NP24-I. In addition, some allergenic motifs bearing high similarity/identity with some predicted Ig-E binding motifs of closely related allergenic TLPs like Jun a 3 (Juniperus ashei, from mountain cedar pollen) and banana-TLP have been identified on the molecular surface of NP24-I.     

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.     

Genetic modification and plant food allergens: risks and benefits

Plant genetic engineering has the potential to both introduce new allergenic proteins into foods and remove established allergens. A number of allergenic plant proteins have been characterized, showing that many are related to proteins which have potentially valuable properties for use in nutritional enhancement, food processing and crop protection. It is therefore important to monitor the allergenic potential of proteins used for plant genetic engineering and major biotechnology companies have established systems for this. Current technology allows gene expression to be down-regulated using antisense or co-suppression and future developments may allow targeted gene mutation or gene replacement. However, the application of this technology may be limited at least in the short term by the presence of multiple allergens and their contribution to food processing or other properties. Furthermore, the long-term stability of these systems needs to be established as reversion could have serious consequences.     

Homology modeling of allergenic cyclophilins: IgE-binding site and structural basis of cross-reactivity

Cross-reactivity among allergens is of considerable scientific as well as clinical interest. Proteins belonging to the allergenic cyclophilin family share a high degree of sequence homology and are cross-reactive. Until date no three-dimensional structural information is available on these proteins and the shared structural features of the epitopes which are the most important determinants of cross-reactivity. Cyclophilins are also known to bind with the immuno-suppressive drug cyclosporin. Comparative molecular modeling of these allergenic cyclophilin proteins of different sources was performed in order to investigate the structural basis of their cross-reactivity. All the proteins studied revealed a similarity in the shape of the cross-reactive epitopes with varying degrees of accessibility. Cyclosporin binding and allergenic properties of these proteins were also found to be structurally related.     

The role of the intine and cytoplasm in the activation and germination processes of Poaceae pollen grains

Ultrastructural modifications of the intine and cytoplasm, during the maturation, activation and germination processes are described for several Poaceae pollen grains. Allergenic and antigenic proteins were found in the non apertural intine during the times of activation and germination, using TEM immunolabelling. This fact may be related to the function of the non apertural intine during the processes of pollen activation and pollen tube formation prior to fecundation. Changes in the granular particles of the cytoplasm are described and their role in pollen wall development is suggested. The pectic‐cellulosic and callosic layers of the pollen tube were formed on the degraded intine, and a relationship between pollen tube wall development and the substances expelled from the fibrillar particles was observed. The immunolabelling of the starch granules may be in agreement with their role in the allergenic process.     

Allergenicity assessment of genetically modified crops--what makes sense?

GM crops have great potential to improve food quality, increase harvest yields and decrease dependency on certain chemical pesticides. Before entering the market their safety needs to be scrutinized. This includes a detailed analysis of allergenic risks, as the safety of allergic consumers has high priority. However, not all tests currently being applied to assessing allergenicity have a sound scientific basis. Recent events with transgenic crops reveal the fallacy of applying such tests to GM crops.     

Food allergen detection by mass spectrometry: From common to novel protein ingredients

Food allergens are molecules, mainly proteins, that trigger immune responses in susceptible individuals upon consumption even when they would otherwise be harmless. Symptoms of a food allergy can range from mild to acute; this last effect is a severe and potentially life-threatening reaction. The European Union (EU) has identified 14 common food allergens, but new allergens are likely to emerge with constantly changing food habits. Mass spectrometry (MS) is a promising alternative to traditional antibody-based assays for quantifying multiple allergenic proteins in complex matrices with high sensitivity and selectivity. Here, the main allergenic proteins and the advantages and drawbacks of some MS acquisition protocols, such as multiple reaction monitoring (MRM) and data-dependent analysis (DDA) for identifying and quantifying common allergenic proteins in processed foodstuffs are summarized. Sections dedicated to novel foods like microalgae and insects as new sources of allergenic proteins are included, emphasizing the significance of establishing stable marker peptides and validated methods using database searches. The discussion involves the in-silico digestion of allergenic proteins, providing insights into their potential impact on immunogenicity. Finally, case studies focussing on microalgae highlight the value of MS as an effective analytical tool for ensuring regulatory compliance throughout the food control chain.     

Prediction of Bacterial and Archaeal Allergenicity with AllPred Program

Nowadays, allergic disorders have become one of the most important social problems in the world. This can be related to the advent of new allergenic agents in the environment, as well as an increasing density of human contact with known allergens, including various proteins. Thus, the development of computer programs designed for the prediction of allergenic properties of proteins becomes one of the urgent tasks of modern bioinformatics. Previously we developed a web accessible Allpred Program (http://www-bionet.sscc.ru/ psd/cgi-bin/programs/Allpred/allpred.cgi) that allows users to assess the allergenicity of proteins by taking into account the characteristics of their spatial structure. In this paper, using AllPred, we predicted the allergenicity of proteins from 462 archaea and bacteria species for which a complete genome was available. The segregation of considered proteins on archaea and bacteria has shown that allergens are predicted more often among archaea than among bacteria. The division of these proteins into groups according to their intracellular localization has revealed that the majority of allergenic proteins were among the secreted proteins. The application of methods for predicting the level of gene expression of microorganisms based on DNA sequence analysis showed a statistically significant relationship between the expression level of the proteins and their allergenicity. This analysis has revealed that potentially allergenic proteins were more common among highly expressed proteins. Sorting microorganisms into the pathogenic and nonpathogenic groups has shown that pathogens can potentially be more allergenic because of a statistically significant greater number of allergens predicted among their proteins.     

Distribution pattern of allergenic plants in the Beijing metropolitan region

Urbanization has significantly affected the composition and distribution pattern of plant species within and around cities. Plants with airborne pollens can cause seasonal allergic symptoms that are intensified by increasing air pollution and temperature. In urban landscapes, the reduced native biodiversity, increased exotic biodiversity, and species homogenization may all affect the abundance and distribution of allergenic plants. We investigated the plants with airborne pollens in the Beijing metropolitan region to determine the distribution pattern of allergenic plants as influenced by urbanization. Our results show that native allergenic plants dominated the urban area in the region. The species richness of allergenic plants, particularly the exotic plants with airborne pollens, significantly differed between land use types. The higher the plant diversity in the urban area, the higher the frequency of allergenic plant occurrence. Despite the homogenization of the allergenic plant communities, their characteristic species were still present across the metropolitan region. The flowering allergenic plants also differed between the different land use types. We suggest that some common allergenic plants should be avoided by urban planners, especially those that are exotic to the region. Humans susceptible to pollinosis should stay away from places that are concentrated with allergenic plants, and be aware of the flowering phenology of allergenic plants.     

The fauna, number and spatial distribution of mites (Acari) in house dust in Moscow

There is a wide and strong allergenic background in Moscow, which is determined by relatively high population density and regular frequency of the allergenic mites in various premises. 34 species have been identified, 5 of them are allergen producers. The mites of the family Pyroglyphidae are the main component of the house dust fauna. Dermatophagoides pteronyssinus and D. farinae distributed all over the world are predominate. A comparative evaluation of the fauna structure, numbers and frequency of the allergenic mites in the flat dust of the allergic patients and healthy people as well as premises is given. Possible importance of the premises in prevalence and circulation of the allergenic mites in the modern town is estimated for the first time.     

Immunocytochemical localization of the allergenic proteins in the pollen of Cryptomeria japonica

Applying an immunocytochemical method, a localization of the protein Cry j I in the Cryptomeria japonica pollen, which is the major allergen responsible for Japanese cedar pollinosis, is investigated with the monoclonal and polyclonal antibodies produced from the protein. The protein that reacts to the polyclonal antibody localizes on the sexine, nexine, between nexine and intine layers, orbicles, cell wall of a generative cell, Golgi body and Golgi vesicles. The allergenic protein contained in the exine and orbicles of Japanese cedar pollen can diffuse or dissolve easily from there into the mucus covering of the eye and nose, causing a response in less than 1 min after exposure. Since the orbicles have a diameter of about 430 nm, they can pass easily through the pores of most protective masks to reach the sensitive tissues of the patient. The proteins react to the monoclonal antibodies (J1BO1 and J1BO7) and localize on the Golgi body, sexine, nexine and orbicles (but not between the nexine and intine layers), and on the generative cell wall. In the young pollen grain, numerous allergenic protein particles contained in the orbicles and sexine layer, but there is only a small amount of the protein between the nexine and intine layers, since the intine layer is not yet complete at this stage. More will be accumulated there during developmental maturation. The allergenic protein is also found on the tapetal materials remaining in the young anther. Since the materials forming the exine layer and orbicles come from tapetal tissue, it is assumed that some of the allergenic protein is produced in the tapetum and localized in the orbicles and pollen wall during maturation, and that the rest of the allergenic protein is produced in the Golgi body in the mature pollen grain.     

Diagnosis of <Emphasis Type="Italic">Chenopodium album</Emphasis> allergy with a cocktail of recombinant allergens as a tool for component-resolved diagnosis

Chenopodium album pollen is one of the main sources of pollen allergy in desert and semi-desert areas and contains three identified allergens, so the aim of this study is comparison of the diagnostic potential of C. album recombinant allergens in an allergenic cocktail and C. album pollen extract. Diagnostic potential of the allergenic cocktail was investigated in 32 individuals using skin prick test and obtained results were compared with the acquired results from C. album pollen extract. Specific IgE reactivity against the pollen extract and allergenic cocktail was determined by ELISA and western blotting tests. Inhibition assays were performed for the allergenic cocktail characterization. The exact sensitization profile of all patients was identified which showed that 72, 81 and 46% of allergic patients had IgE reactivity to rChe a 1, rChe a 2 and rChe a 3, respectively. Almost all of C. album allergic patients (30/32) had specific IgE against the allergenic cocktail. In addition, there was a high correlation between IgE levels against the allergenic cocktail and IgE levels against the pollen extract. The allergenic cocktail was able to completely inhibit IgE binding to natural Che a 1, Che a 2 and Che a 3 in C. album extract. In addition, positive skin test reactions were seen in allergic patients that tested by the allergenic cocktail. The reliable results obtained from this study confirmed that the allergenic cocktail with high diagnostic potential could be replaced with natural C. album allergen extracts in skin prick test and serologic tests.