Novel Allergen Discovery through Comprehensive De Novo Transcriptomic Analyses of Five Shrimp Species.

Shaymaviswanathan Karnaneedi,Andreas L Lopata,Dean R Jerry,Roger Huerlimann,Roni Nugraha,Sandip D Kamath,Nicholas M Wade,Thimo Ruethers,Elecia B Johnston,Aya C Taki

doi:10.3390/ijms22010032

Abstract

Shellfish allergy affects 2% of the world’s population and persists for life in most patients. The diagnosis of shellfish allergy, in particular shrimp, is challenging due to the similarity of allergenic proteins from other invertebrates. Despite the clinical importance of immunological cross-reactivity among shellfish species and between allergenic invertebrates such as dust mites, the underlying molecular basis is not well understood. Here we mine the complete transcriptome of five frequently consumed shrimp species to identify and compare allergens with all known allergen sources. The transcriptomes were assembled de novo, using Trinity, from raw RNA-Seq data of the whiteleg shrimp (Litopenaeus vannamei), black tiger shrimp (Penaeus monodon), banana shrimp (Fenneropenaeus merguiensis), king shrimp (Melicertus latisulcatus), and endeavour shrimp (Metapenaeus endeavouri). BLAST searching using the two major allergen databases, WHO/IUIS Allergen Nomenclature and AllergenOnline, successfully identified all seven known crustacean allergens. The analyses revealed up to 39 unreported allergens in the different shrimp species, including heat shock protein (HSP), alpha-tubulin, chymotrypsin, cyclophilin, beta-enolase, aldolase A, and glyceraldehyde-3-phosphate dehydrogenase (G3PD). Multiple sequence alignment (Clustal Omega) demonstrated high homology with allergens from other invertebrates including mites and cockroaches. This first transcriptomic analyses of allergens in a major food source provides a valuable resource for investigating shellfish allergens, comparing invertebrate allergens and future development of improved diagnostics for food allergy.

Highlights

Food allergy affects up to 10% of children and 10% of adults, and the prevalence is projected to rise [1,2]
The inclusion of house dust mite (HDM) and cockroach tropomyosin allergens, Der p 10 (AAB69424), Bla g 7 (AAF72534) and Per a 7 (CAB38086), in the analyses demonstrated that all three allergens have more than 70% pairwise identity (PI) with shrimp TM, ranging from 72% to 83%
The other two mite allergen AA sequences that matched with a PI of more than 70% to the shrimp transcriptomes are alpha-tubulin (Der f 33, AIO08861) and chymotrypsin (Der f 6, AAP35065) of the American HDM D. farinae (Table 2)

Summary

Introduction

Food allergy affects up to 10% of children and 10% of adults, and the prevalence is projected to rise [1,2]. Shellfish allergy is often lifelong, affects about 2% of the global population and is highly prevalent in the Asia-Pacific region and other countries where seafood consumption is high [8,9,10,11]. Among shellfish-allergic individuals, shrimp allergy seems to be the most prominent crustacean allergy and remains to be difficult to diagnose and manage, for multiple reasons. Shrimp accounts for one of the most prevalent events of food-derived anaphylactic reactions after peanuts and tree nuts [12,13,14,15]

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