Assessment of soy aeroallergen levels in different work environments

Human-Soybean Allergies: Elucidation of the Seed Proteome and Comprehensive Protein-Protein Interaction Prediction

The soybean crop, Glycine max (L.) Merr., is consumed by humans, Homo sapiens, worldwide. While the respective bodies of literature and -omics data for each of these organisms are extensive, comparatively few studies investigate the molecular biological processes occurring between the two. We are interested in elucidating the network of protein-protein interactions (PPIs) involved in human-soybean allergies. To this end, we leverage state-of-the-art sequence-based PPI predictors amenable to predicting the enormous comprehensive interactome between human and soybean. A network-based analytical approach is proposed, leveraging similar interaction profiles to identify candidate allergens and proteins involved in the allergy response. Interestingly, the predicted interactome can be explored from two complementary perspectives: which soybean proteins are predicted to interact with specific human proteins and which human proteins are predicted to interact with specific soybean proteins. A total of eight proteins (six specific to the human proteome and two to the soy proteome) have been identified and supported by the literature to be involved in human health, specifically related to immunological and neurological pathways. This study, beyond generating the most comprehensive human-soybean interactome to date, elucidated a soybean seed interactome and identified several proteins putatively consequential to human health.

Comparison of Allergenicity at Gly m 4 and Gly m Bd 30K of Soybean after Genetic Modification

Despite rapid growth of genetically modified (GM) crops, effective evaluations of genetic modification on allergenicity are still lacking. Gly m Bd 30K is cross-reactive with cow's milk protein casein, Gly m 4, and with birch pollen allergen Bet v 1. Here we compared the allergenicity between GM and non-GM soybeans with respect to the foci Gly m 4 and Gly m Bd 30K. Recombinant allergens of Gly m Bd 30K and Gly m 4 were generated and polyclonal antibodies raised to identify these two allergenic components in soybeans. GM soybean was first PCR-confirmed using 35S promoter. A total of 20 soybeans (half GM, half non-GM) obtained from a food market were used to assess their allergenicity based on IgE-binding and histamine release. The concentrations of Gly m Bd 30K and Gly m 4 in soybeans were then determined. Most soybean-allergic patients (9 of 10) showed IgE-positive reactions to the allergen of 30 kDa in molecular weight. That allergen turned out to be Glycine max Gly m Bd 30K based on LC-MS/MS analyses. Gly m Bd 30K is therefore the major allergen in the soybean. An increase in the transcription of both the Gly m 4 (stress-induced protein SAM22) and Gly m Bd 28K (soybean allergen precursor) was found after genetic modification. The protein concentrations of Gly m 4 and Gly m Bd 30K were not statistically significant different between non-GM and GM soybeans. There were also no statistical significances between them in the tests of IgE binding and histamine release. In conclusion, soybeans showed similar concentrations of Gly m Bd 30K and Gly m 4 regardless of genetic modification or absence thereof. The allergenicity of both Gly m Bd 30K and Gly m 4 was therefore not altered after genetic modification. Patients showing hypersensitivity to soybeans and who had pre-existing allergy to birch pollen and cow's milk casein might not further increase their allergic reactions following exposures to the GM soybeans.

Metaproteomic analysis of atmospheric aerosol samples

Metaproteomic analysis of air particulate matter provides information about the abundance and properties of bioaerosols in the atmosphere and their influence on climate and public health. We developed and applied efficient methods for the extraction and analysis of proteins from glass fiber filter samples of total, coarse, and fine particulate matter. Size exclusion chromatography was applied to remove matrix components, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was applied for protein fractionation according to molecular size, followed by in-gel digestion and LC-MS/MS analysis of peptides using a hybrid Quadrupole-Orbitrap MS. Maxquant software and the Swiss-Prot database were used for protein identification. In samples collected at a suburban location in central Europe, we found proteins that originated mainly from plants, fungi, and bacteria, which constitute a major fraction of primary biological aerosol particles (PBAP) in the atmosphere. Allergenic proteins were found in coarse and fine particle samples, and indications for atmospheric degradation of proteins were observed.

Graphical abstract

Cross-reactivity between the soybean protein p34 and bovine caseins

Purpose

Soy-based formulas are widely used as dairy substitutes to treat milk allergy patients. However, reactions to soy have been reported in a small proportion of patients with IgE-mediated milk allergies. The aim of this work was to explore whether P34, a mayor soybean allergen, is involved in this cross-reactivity.

Methods

In vitro recognition of P34 was evaluated by immunoblotting, competitive ELISA and basophil activation tests (BAT) using sera from allergic patients. In vivo cross-reactivity was examined using an IgE-mediated milk allergy mouse model.

Results

P34 was recognized by IgE antibodies from the sera of milk allergic patients, casein-specific monoclonal antibodies, and sera from milk-allergic mice. Spleen cells from sensitized mice incubated with milk, soy or P34 secreted IL-5 and IL-13, while IFN-γ remained unchanged. In addition, the cutaneous test was positive with cow's milk proteins (CMP) and P34 in the milk allergy mouse model. Moreover, milk-sensitized mice developed immediate symptoms following sublingual exposure to P34.

Conclusions

Our results demonstrate that P34 shares epitopes with bovine casein, which is responsible for inducing hypersensitivity symptoms in milk allergic mice. This is the first report of the in vivo cross-allergenicity of P34.

[Soybean hull unloading in Tarragona (Spain) and asthma outbreak risk]

OBJECTIVES

From 2007 to 2008, 215,000 tons of soybean hull were unloaded in the Port of Tarragona. Soybean hull was identified as the etiologic agent causing bronchial asthma outbreaks. The aim of the present study was to identify the characteristics of soybean unloading, soybean allergen dispersion, and the population risk.

METHODS

Data on soybean hull unloading, carriage and storage, meteorological conditions and the number of emergency room admissions for asthma were recorded. Allergen concentrations were obtained by sampling PM(10) filters retaining particles of less than 10 microns for 24 hours in the atmospheric contamination surveillance stations. Sensitized patients underwent clinical examination consisting of skin prick test, total and specific IgE and immunoblotting to soybean extracts.

RESULTS

Allergen emissions were moderate at one kilometer from the unloading source (above 300 U/m(3) on 3 days, maximum 441 U/m(3)). The protein pattern of hull soybean extracts was similar to that found in asthma epidemics in Barcelona. Ninety-two percent of the patients were sensitized to soybean hull extracts. No asthma epidemic was detected during unloading days. In addition to the low molecular weight soybean proteins identified in previous studies (6 and 14-17 kDa), high molecular weight proteins were found (14-49 kDa).

CONCLUSIONS

There is allergen dispersion at a short distance from the unloading source, posing a risk to sensitized patients. Technical measures are required during soybean hull operations to reduce particle emissions.

Determination of direct and fugitive PM emissions in a Mediterranean harbour by means of classic and novel tracer methods

Remodelling works are frequent in harbour areas, given that they must adapt to rapidly changing market requirements. Depending on their nature (construction, demolition, etc.), these works may be carried out during long periods of time and thus exert a significant impact on the air quality at the harbours and their surroundings. The air quality at the Valencia harbour was studied during an enlargement project. Four sampling stations aimed to cover the major dust-emitting activities in the harbour. In addition, a sampling campaign was carried out to collect dust materials at their emission sources (e.g., loading and unloading of clinker and petroleum coke, as well as the enlargement works). Differences obtained between PM levels at the monitoring sites were correlated with the distance between sampling stations and enlargement works and/or harbour operations, as well as with the preferential wind direction. In all cases, the days with the highest PM_10 levels were linked to wind directions coinciding with the location of the enlargement works or the clinker and petroleum coke stocks. Classic source apportionment methodologies (PCA and CMB) were applied to the data, but their interpretation was complex due to the similar chemical signatures of PM originating from direct and fugitive emissions from stocked materials (e.g., clinker), and the enlargement works. To overcome this difficulty, a novel non-statistical approach was used to obtain quantitative estimations of the contributions from sources (petroleum coke and clinker), based on the correlation between specific PM components (e.g., carbonaceous species) and source tracers (e.g., V). Finally, a qualitative test using phenolphthalein was devised to identify the presence of clinker on the filters, which provided positive results. This novel tracer approach is thus recommended for harbour authorities.

Soy allergy in perspective

PURPOSE OF REVIEW

The purpose of this paper is to review and discuss studies on soy allergy.

RECENT FINDINGS

In Central Europe soy is a clinically relevant birch pollen-related allergenic food. Crossreaction is mediated by a Bet v 1 homologous protein, Gly m 4. Additionally, birch pollen allergic patients might acquire through Bet v 1 sensitization allergies to mungbean or peanut, in which Vig r 1 and Ara h 8 are the main cross-reactive allergens. Threshold doses in soy allergic individuals range from 10 mg to 50 g of soy and are more than one order of magnitude higher than in peanut allergy. No evidence was found for increased allergenicity of genetically modified soybeans.

SUMMARY

In Europe, both primary and pollen-related food allergy exist. The diagnosis of legume allergy in birch pollen-sensitized patients should not be excluded on a negative IgE testing to legume extracts. Bet v 1 related allergens are often underrepresented in extracts. Gly m 4 from soy and Ara h 8 from peanut are nowadays commercially available and are recommended in birch pollen allergic patients with suspicion of soy or peanut allergy, but negative extract-based diagnostic tests to screen for IgE specific to these recombinant allergens.