Genome-Wide Identification and Comparative Analysis of Allergens in Procambarus clarkii

Crustacean shellfish is one of the eight most common food allergens, and crayfish is a highly valued shellfish species for consumption in China. However, the detailed allergen profile of crayfish remains unknown, with only four allergen groups reported in the WHO/IUIS allergen nomenclature database. In this study we aimed to identify novel allergens based on the Procambarus clarkii genome and to reveal its allergen profile for developing better diagnostic tools and treatments.

We assembled the crayfish genome using both long-read and short-read sequencing data and identified putative allergens using the BLAST algorithm based on sequence homology. We employed bioinformatics tools to investigate the expression levels, gene structure, and synteny of these putative allergens. We also applied indirect enzyme-linked immunosorbent assay by using patients' sera to determine allergenicity and utilized proteomic methods to identify novel allergens.

We identified a total of 11 putative allergen groups, including all isoforms or homologs for each allergen group based on the genome and three putative allergens by using 2-dimensional (2D) mass spectrometry. We identified 2 novel allergens, pPro c 3.0301 and pPro c 6.0201, with immunoglobulin E reactivity of 33.3% and 20%, respectively.

By providing a comprehensive understanding of the complete allergen profile, our study presents a foundation for comprehending P. clarkii-associated allergy. The knowledge could facilitate the implementation of a components-resolved diagnostic test and preventive immunotherapy based on molecular allergens for crayfish allergy.