Effect of Non-Thermal Plasma on the Allergenicity of Airborne Allergens

HUNTER RICHARDS, Zhenyu Ma, Herek L. Clack, University of Michigan

     Abstract Number: 517
     Working Group: Health-Related Aerosols

Abstract
Introduction
An allergic reaction is an immune response in which Immunoglobulin E (IgE) antibodies are produced in response to foreign substances that are typically considered harmless. Allergens are proteins or glycoproteins that can induce IgE antibody production in genetically predisposed individuals (Torres-Borrego & Sanchez-Solis 2023; Bannon 2004).

Anaphylaxis is a severe and potentially fatal allergic reaction that is rapid in onset. Airborne anaphylaxis is defined as the occurrence of anaphylactic reactions to inhaled allergens rather than through contact or ingestion. Anaphylaxis through inhalation is a much less frequent route and is largely understudied but may also go undiagnosed or unreported. Foods found to trigger reactions through inhalation include cow’s milk, peanut, sesame, and lentils (Ridolo et al. 2022). The current guidance on prevention of airborne anaphylaxis includes avoidance of environments where allergen aerosols or vapors may be present. However, it is not always possible to entirely avoid exposure and this presents a dangerous situation for highly sensitive individuals.

Nonthermal plasma (NTP) has been studied for its applications within food safety, with uses that include reducing the impacts of microorganisms, foodborne pathogens, and chemical contaminants (Pignata et al. 2017), among others. NTP produces reactive species, such as ·OH and 1O2, that can denature proteins (Bora et al. 2022). NTP plasma was found to induce changes in the secondary structure of Ara h 1 and reduce IgG-binding capacity of Ara h 1 in whole peanut and dry defatted peanut flour for bulk surface treatments (Venkataratnam et al. 2019). Based on the success of reducing allergenicity of peanuts when treated by NTP on surfaces, we expect to see similar results for airborne applications.

Non-thermal plasma was shown to reduce the amount of a 64 kDa protein band, corresponding to peanut allergen Ara h 1, using Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) (Hsu et al. 2023). The immunoreactivity of Ara h 1 was significantly decreased as plasma treatment time increased, shown with immunoblotting and enzyme-linked immunosorbent assay (ELISA) (Hsu et al. 2023).

With this understanding that proteins are susceptible to NTP treatment, there is potential for NTP to be successful in denaturing airborne allergens to the point that their allergenicity is reduced.

Experimental Procedure
Using commercially available peanuts and peanut flour, aerosolized peanut solutions are treated with nonthermal plasma. Samples with and without treatment at the inlet and outlet of the nonthermal plasma reactor are analyzed with gel electrophoresis to assess changes in known allergens.

Ara h 1 migrates as a 63-kDa band, Ara h 2 migrates as a doublet at 20 and 17 kDa, and Ara h 3 consists of a series of polypeptides from 45 to 14 kDa (Yapo-Crezoit et al. 2017). We expect the results of untreated airborne peanut samples to be similar to these results when analyzed with gel electrophoresis, while treated samples would exhibit a change in the distribution and intensity of bands indicating a change in proteins.

Changes in the characteristics of molecular weights may cause changes in allergenicity (Venkataratnam et al. 2019). Analyzing a sample with an Enzyme-Linked ImmunoSorbent Assay (ELISA), the change in allergenicity of aerosolized peanut solutions following nonthermal plasma treatment is evaluated to determine optimal treatment methodology.

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