Ambrosia Artemisiifolia Pollen Research Articles

Plant growth traits and allergenic potential of Ambrosia artemisiifolia pollen as modified by temperature and NO2

Ongoing global warming favors the spread of thermo-tolerant plant species including plants with a high allergenic risk such as common ragweed (Ambrosia artemisiifolia). To assess effects of temperature increase on plant traits and biochemical processes potentially associated with allergenicity, we performed a phytotron chamber experiment which included two levels of temperature (control, elevated by 4 °C) simulated at 10 min resolution, and NO2 (0 ppb, 80 ppb added at a constant rate), respectively, and their combination in a full factorial design. The aim was to evaluate effects of temperature on various parameters related to ragweed allergenicity relative to effects of a known enhancer of allergenicity such as NO2, including the interaction between temperature and NO2. As plant growth parameters, we assessed plant height, male inflorescence size, start and end date of pollen release as well as average pollen release per inflorescence. As pollen traits, we determined pollen allergenicity by dot blot and biochemical factors that may enhance (oxidative stress indicators) or attenuate (flavonoids) pollen allergenicity. We tested the hypotheses that elevated temperatures do not increase the stress level of thermophilic ragweed and thus do not affect allergenicity, whereas NO2 increases allergenicity independent of temperature. Two-way ANOVA results revealed that elevated temperature significantly enhanced the plant height, the size of male inflorescences, and the duration of pollen release, in addition, significantly delayed pollen release independent of NO2. Pollen release per inflorescence was significantly induced by elevated NO2. As single factors, elevated temperature or NO2 affected allergenicity, moreover, the combined treatment of elevated temperature plus NO2 resulted in increased levels of NAD(P)H oxidase activity, H2O2 content, and highest allergenicity. Concentrations and composition of pollen flavonoids were significantly changed by NO2. Irrespective of treatments, pollen flavonoids were dominated by quercetins, but their overall composition was significantly changed by treatments. Flavonoids from lower temperature treatments showed significantly reduced allergen-IgE binding activities. A common trend observed was that elevated temperatures particularly in combination with NO2, increased the pollen allergenicity.

Plant Growth Traits and Allergenic Potential of Ambrosia Artemisiifolia Pollen Under Simulated Current and Future Temperatures and Different No2 Concentrations

Plant Growth Traits and Allergenic Potential of Ambrosia Artemisiifolia Pollen Under Simulated Current and Future Temperatures and Different No2 Concentrations

Design of an Optimally-Diagnostic Skin Test for Diagnosis of Sensitivity to Eight Allergens: A First-in-Human Study of Dose Escalation and Simultaneous Administration in Chinese Subjects.

BackgroundEight extracts from common native allergens, Artemisia annua pollen, Platanus pollen, Humulus pollen, Betula platyphylla pollen, Ambrosia artemisiifolia pollen, Blattella germanica, cat dander and dog dander were developed for skin prick test (SPT). Since standardization and composition alone cannot guarantee that the allergen extracts are within the concentration range that give the best chance of a true diagnosis, it is necessary to explore the optimal diagnostic concentration (ODC) of allergens in SPT.ObjectiveTo identify the optimal diagnostic concentration of eight allergen extracts in SPT and assess the safety of simultaneous administration.Patients and MethodsPatients with a history of allergic disease were enrolled in this two-part open-label, parallel study. In Study 1, 92 patients were enrolled into eight groups according to their disease-causing allergens and were given three increasing concentrations of the corresponding allergen. In Study 2, 20 patients were divided into two concentration groups and were given all of the eight allergens. Safety and sensitivity were evaluated to determine the optimal diagnostic concentration.ResultsIn Study 1, the sensitivity of seven allergen extracts was >80% at middle and high concentrations, except for Ambrosia artemisiifolia pollen. The optimal diagnostic concentration (in DU/mL) for eight allergens was 33,333, 12,000, 8667, 50,000, 40,000, 3333, 7000, and 5000. In Study 2, the prevalence of adverse events in the two groups was 70% and 80%, respectively. A total of 10 wheals of 8 patients did not subside <24 h after SPTs.ConclusionThe eight allergens showed high sensitivity and safety at a certain concentration, which was defined as optimal diagnostic concentration. The results support further clinical research of investigated allergens and our study offers a scheme to determine the ODC of allergens in SPT.

Laboratory evaluation of the (VIS, IR) scattering matrix of complex-shaped ragweed pollen particles

Ragweed or Ambrosia artemisiifolia pollen is an important atmospheric constituent affecting the Earth's climate and public health. The literature on light scattering by pollens embedded in ambient air is however rather sparse: polarization measurements are limited to the sole depolarization ratio and pollens are beyond the reach of numerically exact light scattering models mainly due to their tens of micrometre size. Also, ragweed pollen presents a very complex shape, with a small-scale external structure exhibiting spikes that bears some resemblance with coronavirus, but also apertures and micrometre holes. In this paper, to face such a complexity, a controlled-laboratory experiment is proposed to evaluate the scattering matrix of ragweed pollen embedded in ambient air. It is based on a newly-built polarimeter, operating in the infra-red spectral range, to account for the large size of ragweed pollen. Moreover, the ragweed scattering matrix is also evaluated in the visible spectral range to reveal the spectral dependence of the ragweed scattering matrix within experimental error bars. As an output, precise spectral and polarimetric fingerprints for large size and complex-shaped ragweed pollen particles are then provided. We believe our laboratory experiment may interest the light scattering community by complementing other light scattering experiments and proposing outlooks for numerical work on large and complex-shaped particles.

The influence of meteorological factors on the dynamic of Ambrosia artemisiifolia pollen in an invaded area

The aim of the present study was to analyse the effect of weather conditions on Ambrosia artemisiifolia airpollen concentrations in the highly invaded area of western Romania. The investigation of Ambrosia pollen concentrations was carried out from 2000 to 2010 by means of the volumetric method. Ambrosia pollen concentrations had increasing trend over study period. The results of cluster analysis show that two main groups were identified: group A, with lower SPI (2000, 2001, 2002, 2003, 2004, 2007) and group B, with much higher SPI (2006, 2008, 2009, 2010). The statistical correlation between pollen concentrations and meteorological factors was determined by Pearson’s test. The relationships between Ambrosia pollen concentrations and meteorological parameters, were further assessed using multiple linear regression techniques. The pollen emissions are affected by meteorological factors in the main pollen season. Our results suggest that the abundance of Ambrosia artemisiifolia in western Romania is massive. The Ambrosia pollen load of Timisoara is most important between 15 August – 15 September. Consequently, this is the most dangerous period of the year for allergic reactions. The investigation of Ambrosia pollen behavior in the atmosphere is a compulsory step for measures to stop the spread and establishing control. Ambrosia pollen represents a major health problem and can be considered the main aeroallergenic plant pollen in our region.

Size-Resolved Single-Particle Fluorescence Spectrometer for Real-Time Analysis of Bioaerosols: Laboratory Evaluation and Atmospheric Measurements.

Characteristic particle size, fluorescence intensity, and fluorescence spectra are important features to detect and categorize bioaerosols. A prototype size-resolved single-particle fluorescence spectrometer (S2FS) was developed to simultaneously measure aerodynamic diameters and fluorescence spectra. Emission spectra are dispersed in 512 channels from 370 to 610 nm, where a major portion of biological fluorescence emission occurs. The S2FS consists of an aerodynamic particle sizer and a fluorescence spectrometer with a 355 nm laser excitation source and an intensified charge-coupled device as the detector. Highly fluorescent particles, such as Ambrosia artemisiifolia pollen and Olea europaea pollen, can be distinguished by the S2FS on a single-particle level. For weakly fluorescent particles, fluorescence spectra can only be obtained by averaging multiple particles (between 100 and 3000) of the same kind. Preliminary ambient measurements in Mainz (Germany, central Europe) show that an emission peak at ∼440 nm was frequently observed for fluorescent fine particles (0.5-1 μm). Fluorescent fine particles accounted for 2.8% on average based on the number fraction in the fine mode. Fluorescent coarse particles (>1 μm) accounted for 8.9% on average based on the number fraction, with strongest occurrence observed during a thunderstorm and in the morning.

Mesoscale atmospheric transport of ragweed pollen allergens from infected to uninfected areas.

Allergenic ragweed (Ambrosia spp.) pollen grains, after being released from anthers, can be dispersed by air masses far from their source. However, the action of air temperature, humidity and solar radiation on pollen grains in the atmosphere could impact on the ability of long distance transported (LDT) pollen to maintain allergenic potency. Here, we report that the major allergen of Ambrosia artemisiifolia pollen (Amb a 1) collected in ambient air during episodes of LDT still have immunoreactive properties. The amount of Amb a 1 found in LDT ragweed pollen grains was not constant and varied between episodes. In addition to allergens in pollen sized particles, we detected reactive Amb a 1 in subpollen sized respirable particles. These findings suggest that ragweed pollen grains have the potential to cause allergic reactions, not only in the heavily infested areas but, due to LDT episodes, also in the regions unaffected by ragweed populations.Electronic supplementary materialThe online version of this article (doi:10.1007/s00484-016-1139-6) contains supplementary material, which is available to authorized users.

Immunoproteomic characterization of Ambrosia artemisiifolia pollen allergens in canine atopic dermatitis

Canine atopic dermatitis (CAD) is an immune system disorder that affects 10–15% of the canine population. Short ragweed (Ambrosia artemisiifolia) pollen represents one of the major seasonal sources of allergenic pollen proteins in Europe, particularly in the Pannonian valley of the Balkan region. In Serbia, about 66% of atopic dogs showed a positive intradermal skin test with its pollen extract, which is second to house dust mites. Therefore, characterization of Ambrosia artemisiifolia pollen components, in terms of defining major and minor allergens that induce clinically manifested allergic reaction in dogs, is important for valid diagnosis and efficient therapy.This study has, for the first time, characterized and identified major Ambrosia artemisiifolia allergens in CAD, using an immunoproteomic approach. To assess the prevalence of specific IgE in electrophoretically separated ragweed pollen proteins, individual reactivity of sera from dogs with CAD was analyzed and compared to the reactivity of sera from healthy dogs in the non-reducing conditions, which were found optimal for specific canine IgE detection. A specific IgE band (38kDa) was recognized as the most dominant allergen in CAD, occurring in 81% of positive dog's sera. 2-D immunoblotting followed by a mass spectrometry peptide fingerprint analyses with pooled canine and human atopic sera, revealed that 38kDa major Ambrosia atremisiifolia allergens in CAD were all five isoallergens of the Amb a 1 group (antigen E), including the previously named Amb a 2 (antigen K). In contrast to canine sera, human atopic sera also recognized lower mass allergens such as the β fragment of Amb a 1 and profilins (Amb a 8 variants).The most prominent ragweed proteins in CAD, represent, as in humans, variants of all five isoallergens of the Amb a 1 group (pectate lyase): Amb a 1.0101 and its natural variant E1XUL2, Amb a 1.0202, 1.0304, 1.0402 and the natural variant of Amb a 1.0501, E1XUM0, as well as the α fragment of pollen allergen Amb a 1.0201.

Evaluation of criteria for diagnosis of atopic dermatitis and detection of allergen specific IgE antibodies in dogs allergic to Ambrosia artemisiifolia pollen

Common ragweed (Ambrosia atremisiifolia) is one of the most frequent causes of pollen-induced allergic reactions both in humans and dogs. It has not been defined yet, what is the major allergen(s) to which most dogs allergic to ragweed show a positive result on intradermal skin test (IDST). In the present study sensitization to Ambrosia artemisiifolia pollen allergens in dogs with atopic dermatitis was examined with both in vivo and in vitro tests, including IDST and serum allergen specific IgE test. Detection of specific-IgE antibodies against ragweed allergens by immunoblotting in the sera of allergic dogs was optimized, as well. Dogs that were positive, as judged by IDST reactions to ragweed pollen allergens, also had alergen specific IgE antibodies in their sera. Results indicate that major allergens of A. artemisifolia pollen in dogs are Amb a 1 and Amb a 2. Further characterization of ragweed allergens is needed before they could potentially be used in intradermal testing or allergen immunotherapy in affected dogs. Also, we evaluated new Favrots diagnostic criteria for canine atopic dermatitis in dogs allergic to Ambrosia atremisiifolia pollen. It might be concluded that proposed criteria are of great assistance for seting up suspected diagnosis of canine atopic dermatitis, after ruling out other pruritic dermatoses. [Projekat Ministarstva nauke Republike Srbije, br. 172024]

Comparison of the Rotorod to other air samplers for the determination of Ambrosia artemisiifolia pollen concentrations conducted in the Environmental Exposure Unit

The Environmental Exposure Unit (EEU) is a 924 m3 facility (Kingston General Hospital, Ontario) in which uniform concentrations of various pollens in HEPA-filtered air at known rates of laminar airflow can be maintained. This facility provided a unique opportunity to compare several air samplers without the environmental variation inherent in outdoor comparisons. The purpose of this study was to conduct a quantitative comparison of pollen measurements using the Rotorod, Burkard™ Personal Volumetric Air Sampler, Air-O-Cell™ and a 37 mm open-faced filter cassette with a microporous filter in the EEU. Pollen samples were taken during clinical trials being conducted in the Unit. Raw pollen counts/m3 obtained using the different methods were corrected using published particle collection efficiencies for the particle size (∼ ∼20 μm) and airflow. Data were analyzed by ANOVA/Tukey HSD. No statistically significant differences were found between pollen concentrations determined by Rotorod, Air-O-Cell and filter cassette. Pollen levels determined by the Burkard were up to 2 times higher than the other sampling methods. Relative standard deviations were similar for the Rotorod, Burkard, and filter cassette and higher for the Air-O-Cell. This study demonstrated that, under our conditions, the Rotorod sampler provides consistent and reliable measurements of ragweed pollen concentrations.

Effect of pollen-mediated oxidative stress on immediate hypersensitivity reactions and late-phase inflammation in allergic conjunctivitis

Allergic eye diseases are complex inflammatory conditions of the conjunctiva that are becoming increasingly prevalent and present an increasing economic burden because of direct and indirect health expenditures. We sought to identify factors that may synergize with antigen-induced allergic inflammation and lead to allergic conjunctivitis. We used a murine model of allergic conjunctivitis to test the effect of oxidative stress generated by pollen oxidases using nicotinamide adenine dinucleotide (reduced) or nicotinamide adenine dinucleotide phosphate (reduced) (NAD[P]H) as an electron donor present in pollen grains. Reactive oxygen species (ROS) generation by hydrated Ambrosia artemisiifolia pollen (short ragweed pollen; RWP) grains was determined by using 2'-7'-dihydro-dichlorofluorescein diacetate, nitroblue tetrazolium reduction, and Amplex Red assay. The RWP-induced changes in intracellular ROS levels were examined in A549 cells, human primary bronchial epithelial cells, and murine conjunctiva. Ragweed pollen grains contain NAD(P)H oxidase activity, which is diphenyleneiodonium-sensitive and quinacrine-sensitive and sodium azide-resistant. These NAD(P)H oxidases generate a superoxide anion that can be converted to H2O2 by pollen grain-associated superoxide dismutase. These diffusible oxygen radicals from pollen grains increase intracellular ROS levels in cultured epithelial cells and murine conjunctiva. Similar phenomena were observed in sensitized and naive mice, indicating that the RWP-induced oxidative stress in conjunctival epithelium is independent of adaptive immunity. Inactivation of NAD(P)H oxidase activity in RWP decreases the immediate-type hypersensitivity and inflammatory cell infiltration into the conjunctiva. Our data suggest that ROS generated by NAD(P)H oxidases in pollen grains intensify immediate allergic reactions and recruitment of inflammatory cells in murine conjunctiva.

Comparison of the Rotorod sampler to three other methods for the determination of Ambrosia artemisiifolia pollen concentrations in the environmental exposure unit

Comparison of the Rotorod sampler to three other methods for the determination of Ambrosia artemisiifolia pollen concentrations in the environmental exposure unit