Recombinant Tropomyosin from the Pacific Oyster (Crassostrea gigas) for Better Diagnosis.

Roni Nugraha,Shaymaviswanathan Karnaneedi,Aya C Taki,Thimo Ruethers,Elecia B Johnston,Andreas L Lopata,Sandip D Kamath

doi:10.3390/foods11030404

Abstract

The Pacific oyster is a commercially important mollusc and, in contrast to most other shellfish species, frequently consumed without prior heat treatment. Oysters are rich in many nutrients but can also cause food allergy. Knowledge of their allergens and cross-reactivity remains very limited. These limitations make an optimal diagnosis of oyster allergy difficult, in particular to the Pacific oyster (Crassostrea gigas), the most cultivated and consumed oyster species worldwide. This study aimed to characterise IgE sensitisation profiles of 21 oyster-sensitised patients to raw and heated Pacific oyster extract using immunoblotting and advanced mass spectrometry, and to assess the relevance of recombinant oyster allergen for improved diagnosis. Tropomyosin was identified as the major allergen recognised by IgE from 18 of 21 oyster-sensitised patients and has been registered with the WHO/IUIS as the first oyster allergen (Cra g 1). The IgE-binding capacity of oyster-sensitised patients’ IgE to purified natural and recombinant tropomyosin from oyster, prawn, and dust mite was compared using enzyme-linked immunosorbent assay. The degree of IgE binding varied between patients, indicating partial cross-sensitisation and/or co-sensitisation. Amino acid sequence alignment of tropomyosin from these three species revealed five regions that contain predicted IgE-binding epitopes, which are most likely responsible for this cross-reactivity. This study fully biochemically characterises the first and major oyster allergen Cra g 1 and demonstrates that the corresponding recombinant tropomyosin should be implemented in improved component-resolved diagnostics and guide future immunotherapy.

Highlights

Consumption of shellfish has increased considerably in the last two decades due to the high nutrient content and health benefits [1]
The analysis of raw and cooked extracts of Pacific oyster by 1-dimensional SDS-PAGE showed various proteins with a molecular weight ranging from 10 to 200 kDa (Figure 1)
The results showed that patients which recognised oyster TM demonstrated IgE reactivity with Pen m 1 from prawn and Der p 10 from dust mite

Summary

Introduction

Consumption of shellfish has increased considerably in the last two decades due to the high nutrient content and health benefits [1]. Crustacean and mollusc, form the shellfish group and consist of hundreds of different species consumed globally. The Food and Agricultural Organization lists over 60 crustacean and 120 mollusc species that are widely consumed (FAO http://www.fao.org/fishery/statistics/globalconsumption/en (accessed on 6 September 2017). The increasing consumption of shellfish has been associated with the increasing incidence of allergic reactions to shellfish. Many studies have shown that dietary habits correlate directly with food allergy prevalence. Many consumers are introduced to new shellfish species due to the better distribution and globalisation of shellfish-based food products

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