Novel Approaches for Inhibiting the Indoor Allergen Der f 2 Excreted from House Dust Mites by Todomatsu Oil Produced from Woodland Residues.

House dust mite (HDM) is a globally ubiquitous domestic cause of allergic diseases. There is a pressing demand to discover efficient, harmless, and eco-friendly natural extracts to inhibit HDM allergens that are more likely to trigger allergies and challenging to be prevented entirely. This study, therefore, is aimed at assessing the inhibition of the allergenicity of major HDM allergen Der f 2 by todomatsu oil extracted from residues of Abies Sachalinensis. The inhibition was investigated experimentally (using enzyme-linked immunosorbent assay (ELISA), surface plasmon resonance (SPR), and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)) and in silico using molecular docking. The results showed that todomatsu oil inhibits the allergenicity of Der f 2 by reducing its amount instead of the IgG binding capacity of a single protein. Moreover, the compounds in todomatsu oil bind to Der f 2 via alkyl hydrophobic interactions. Notably, most compounds interact with the hydrophobic amino acids of Der f 2, and seven substances interact with CYS27. Contrarily, the principal compounds fail to attach to the amino acids forming the IgG epitope in Der f 2. Interestingly, chemical components with the lowest relative percentages in todomatsu oil show high-affinity values on Der f 2, especially ß-maaliene (-8.0 kcal/mol). In conclusion, todomatsu oil has been proven in vitro as a potential effective public health strategy to inhibit the allergenicity of Der f 2.

Characterization of allergenicity of Platanus pollen allergen a 3 (Pla a 3) after exposure to NO2 and O3.

Pollen allergens, widely present in the atmosphere, are the main cause of seasonal respiratory diseases that affect millions of people worldwide. Although previous studies have reported that nitrogen dioxide (NO2) and ozone (O3) promote pollen allergy, the specific biological processes and underlying mechanisms remain less understood. In this study, Platanus pollen grains were exposed to gaseous pollutants (NO2 and O3). We employed environmental electron microscopy, flow cytometry, western blot assay, enzyme-linked immunoassay, ultraviolet absorption spectrometry, circular dichroism, and protein mass spectrometry to characterise the subpollen particles (SPPs) released from pollen grains. Furthermore, we determined the immunogenicity and pathogenicity induced by Platanus pollen allergen a 3 (Pla a 3). Our results demonstrated that NO2 and O3 could damage the pollen cell membranes in SPPs and increase the amount of Pla a 3 allergen released into the atmosphere. Additionally, NO2 and O3 altered the structure of Pla a3 protein through nitrification and oxidation, which not only enhanced the immunogenicity of allergens but also increased the stability of the protein. In vivo analysis using an animal model indicated that NO2 and O3 greatly aggravated pollen-induced pneumonia. Thus, our study provides guidance for the prevention of pollen allergic diseases.

Studies on relationships between air pollutants and allergenicity of Humulus Scandens pollen collected from different areas of Shanghai.

Pollen pollution and allergy are becoming prominent issues in China. However, few studies on pollinosis have been reported. As an allergen in the atmosphere, allergenic Humulus scandens pollen was collected from four districts of Shanghai, including Wusong (WS), Jiading (JD), Xujiahui (XJH) and Songjiang (SJ). The mass concentrations of SO2, NO2, O3, PM10, and PM2.5 (particulate matter with air dynamic diameter less than 10 and 2.5 µm, respectively) near the four sampling sites were also recorded during Humulus scandens pollen season. The allergenicity of the Humulus scandens pollen was assessed by using of a rat model and enzyme linked immunosorbent assay (ELISA). Relationships between the allergenicity and air pollutants were correlated. Our results demonstrated that the biological viability of the pollens collected from the four districts exhibited no significant differences. ELISA and dot blotting results further demonstrated that the serum of sensitized rats exhibited much higher immune-reactive response than that of control groups. Western blotting showed that the 15 KD (1KD = 1000 dalton) proteins of Humulus pollen led to the allergic response. The allergenic intensity of Humulus pollen protein from different samples followed the pattern: WS > JD > XJ > SJ. There was a negative relationship between the allergenicity of Humulus pollens and PM10 (R = -0.99) / PM2.5 (R = -0.73), and a positive relationship with O3 (R = 0.92). These data clearly showed that PM10 and PM2.5 could enhance Humulus pollen protein release, and O3 could aggravate the allergenicity of the Humulus pollen.

Allergenicity of recombinant Humulus japonicus pollen allergen 1 after combined exposure to ozone and nitrogen dioxide.

Ozone (O3) and nitrogen dioxide (NO2) are thought to play primary roles in aggravating air pollution-induced health problems. However, the effects of joint O3/NO2 on the allergenicity of pollen allergens are unclear. Humulus japonicus pollen allergen 1 (Hum j1) is a profilin protein that causes widespread pollinosis in eastern Asia. In order to study the effects of combined O3/NO2 on the allergenicity of Hum j1, tandem six-histidine peptide tag (His6)-fused recombinant Hum j1 (rHum j1) was expressed in a prokaryotic system and purified through His6 affinity chromatography. The purified rHum j1 was used to immunize SD rats. Rat sera with high titers of IgG and IgE antibodies against rHum j1 were used for allergenicity quantification. The rHum j1 was exposed to O3/NO2, and changes in allergenicity of the exposed rHum j1 were assayed using the immunized rat antibodies. Tandem LC-MS/LC (liquid chromatography-mass spectrometer/liquid chromatography spectrometer) chromatography and UV and circular dichroism (CD) spectroscopy were used to study the structural changes in rHum j1. Our data demonstrated that a novel disulfide bond between the sulfhydryl groups of two neighboring cysteine molecules was formed after the rHum j1 exposure to joint O3/NO2, and therefore IgE-binding affinity was increased and the allergenicity was reinforced. Our results provided clues to elucidate the mechanism behind air pollution-induced increase in pollinosis prevalence.

[Perspectives on synergic biological effects induced by ambient allergenic pollen and urban fine/ultrafine particulate matters in atmosphere].

Ambient particulate matters (PM) and allergenic pollens in urban atmosphere have taken negative effects on human health and air quality. Studies on synergistic effects between the two pollutants are being focused in disciplines, such as atmospheric sciences, environmental toxicology, and immunology. In this study, physicochemical characterization of airborne fine/ultrafine particles in Shanghai, China and ambient allergenic pollens (cedar) in Kanto, Japan were investigated. We found that allergenic protein particles (Ubisch body) with diameter less than 0.7 microm were absorbed on Japanese cedar pollen, and airborne particles which contained allergenic particles mainly distributed in < 1 microm size range. The highest mass concentration of chemical elements in Shanghai airborne particles was found in the 0.3-0.18 microm size range, but mass level of pollutant elements, such as S and Pb, in ambient in ultrafine (nano) particles were higher than that in coarse and fine particles. And also, pollen particles were found in Shanghai airborne particles. Synergistic effects between diesel exhaust particles (DEPs), which were the main component in urban airborne particles, and ambient pollens in urban atmosphere can be found, but their mechanism have not been clear. After our new results and other conclusions published recently on allergenic pollen and airborne fine/ultrafine particles were summarized, perspectives of this new discipline were presented.