RESULTS: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis fractionated raw snail extract to approximately 24 protein bands, between 9 and 245 kDa. The prominent band at 33 kDa was detected in all raw and processed snail extracts. Immunoblotting tests of the raw extract demonstrated 19 immunoglobulin E (IgE)-binding proteins, and four of them, at 30, 35, 42 and 49 kDa, were revealed as the major IgE-binding proteins of P. polita. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identified the 49 and 42 kDa major allergens as actin, whereas the 30 and 35 kDa major allergens were identified as tropomyosin. Immunoblotting revealed that the raw snail had more allergenic proteins than the processed snail. The degree of allergenicity in decreasing order was raw > brine pickled> boiled > roasted > fried > vinegar pickled. The presence of cross-reactivity between P. polita and the shellfish tested was exhibited with either no, complete, or partial inhibitions.
CONCLUSION: Actin and tropomyosin were identified as the major and cross-reactive allergens of P. polita among local patients with snail allergy. Those major allergens are highly stable to high temperatures, acidic pH, and high salt, which might played a crucial role in snail allergy in Malaysia. © 2023 Society of Chemical Industry.
METHODOLOGY: Proteomics was used to compare protein extracts of skim milk from Saanen, Jamnapari, and Toggenburg. Cow's milk was used as a control. IgE-immunoblotting and mass spectrometry were used to compare and identify proteins that cross-reacted with serum IgE from CMPA patients (n = 10).
RESULTS: The analysis of IgE-reactive proteins revealed that the protein spots identified with high confidence were proteins homologous to common cow's milk allergens such as α-S1-casein (αS1-CN), β-casein (β-CN), κ-casein (κ-CN), and beta-lactoglobulin (β-LG). Jamnapari's milk proteins were found to cross-react with four major milk allergens: α-S1-CN, β-CN, κ-CN, and β-LG. Saanen goat's milk proteins, on the other hand, cross-reacted with two major milk allergens, α-S1-CN and β-LG, whereas Toggenburg goat's milk proteins only react with one of the major milk allergens, κ-CN.
CONCLUSION: These findings may help in the development of hypoallergenic goat milk through cross-breeding strategies of goat breeds with lower allergenic milk protein contents.