Identification and semi-quantification of protein allergens in complex mixtures using proteomic and AllerCatPro 2.0 bioinformatic analyses: a proof-of-concept investigation

Abstract

The demand for botanicals and natural substances in consumer products has increased in recent years. These substances usually contain proteins and these, in turn, can pose a risk for immunoglobulin E (IgE)-mediated sensitization and allergy. However, no method has yet been accepted or validated for assessment of potential allergenic hazards in such materials. In the studies here, a dual proteomic-bioinformatic approach is proposed to evaluate holistically allergenic hazards in complex mixtures of plants, insects, or animal proteins. Twelve commercial preparations of source materials (plant products, dust mite extract, and preparations of animal dander) known to contain allergenic proteins were analyzed by label-free proteomic analyses to identify and semi-quantify proteins. These were then evaluated by bioinformatics using AllerCatPro 2.0 (https://allercatpro.bii.a-star.edu.sg/) to predict no, weak, or strong evidence for allergenicity and similarity to source-specific allergens. In total, 4,586 protein sequences were identified in the 12 source materials combined. Of these, 1,665 sequences were predicted with weak or strong evidence for allergenic potential. This first-tier approach provided top-level information about the occurrence and abundance of proteins and potential allergens. With regards to source-specific allergens, 129 allergens were identified. The sum of the relative abundance of these allergens ranged from 0.8% (lamb’s quarters) to 63% (olive pollen). It is proposed here that this dual proteomic-bioinformatic approach has the potential to provide detailed information on the presence and relative abundance of allergens, and can play an important role in identifying potential allergenic hazards in complex protein mixtures for the purposes of safety assessments.

Keywords:

• Protein allergenicity
• IgE
• risk assessment
• botanicals
• natural substances

Acknowledgements

The authors gratefully acknowledge valuable discussions with reviewers at Procter & Gamble. Minh N. Nguyen would like to thank A*STAR Joint Council Office (JCO) Career Development Award/Fund (222D800029) and HBMS Domain Industry Alignment Fund Pre-Positioning (IAF-PP), A*STAR (H2001a0P14) for funding. Vachiranee Limviphuvadh would like to thank the National Research Foundation, Singapore and A*STAR under the Singapore Food Story R&D Programme (W22W3D0003) and Industry Alignment Fund BMRC, A*STAR/P&G (APG2013/096) for funding.

Disclosure statement

Authors GFG and IK received financial compensation from P&G for their time spent in the preparation of this publication. This article was prepared during the normal course of the authors’ affiliations or employment shown on the first page of the paper. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. None of these authors has participated in legal or regulatory proceedings on the subject of this paper during the last 5 years.

The authors have sole responsibility for the preparation and content of this manuscript.

Additional information

Funding

This work has been supported by The Procter & Gamble Company and the Agency for Science, Technology and Research (A*STAR); The National Research Foundation, Singapore and A*STAR under the Singapore Food Story R&D Programme (W22W3D0003). This research is supported by A*STAR (222D800029).