Malaysian cockle (Anadara granosa) allergy: Identification of IgE-binding proteins and effects of different cooking methods
- Author:
Zailatul, H.M.Y.
;
Rosmilah, M.
;
Faizal, B.
;
Noormalin, A.
;
Shahnaz, M.
- Publication Type:Journal Article
- From:Tropical Biomedicine
2015;32(2):323-334
- CountryMalaysia
- Language:English
-
Abstract:
The purpose of this study was to evaluate the effect of different cooking methods
on the allergenicity of cockle and to identify proteins most frequently bound by IgE antibodies
using a proteomics approach. Raw, boiled, fried and roasted extracts of the cockle were
prepared. The protein profiles of the extracts were obtained by separation using sodium
dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and 2-dimensional gel
electrophoresis (2-DE). IgE-immunoblotting was then performed with the use of individual
sera from patients with cockle allergy and the major IgE-binding proteins were analyzed by
mass-spectrometry. SDS-PAGE of raw extract showed 13 protein bands. Smaller numbers of
protein bands were detected in the boiled, fried and roasted extracts. The 2-DE gel profile of
the raw extract further separated the protein bands to ~50 protein spots with molecular
masses between 13 to 180 kDa and isoelectric point (pI) values ranging from 3 to 10.
Immunoblotting of raw extract exhibited 11 IgE-binding proteins with two proteins of 36 and
40 kDa as the major IgE-binding proteins, while the boiled extract revealed 3 IgE-binding
proteins. Fried and roasted extracts only showed a single IgE-binding protein at 36 kDa. 2-DE
immunoblotting of raw extract demonstrated 5 to 20 IgE reactive spots. Mass spectrometry
analysis led to identification of 2 important allergens, tropomyosin (36 kDa) and arginine
kinase (40 kDa). Heated extracts showed a reduction in the number of IgE-reactive bands
compared with raw extract, which suggest that thermal treatment can be used as a tool in
attempting to reduce cockle allergenicity. The degree of allergenicity of cockle was
demonstrated in the order raw > boiled > fried ≈ roasted. Two important allergens reacting
with more than 50% of patients’ sera identified using mass spectrometric approaches were
tropomyosin and arginine kinase. Thus, allergens found in this study would help in componentbased
diagnosis, management of cockle allergic patients and to the standardisation of allergenic
test products as tools in molecular allergology.
- Full text:W020150709331932965675.pdf
