Effects of Different Lengths Sugar Chains on the Structure and Allergenicity of Allergic Epitopes 13KDLKGYGGVSLPEW26 in α-Lactalbumin

Abstract

The allergic epitopes of α-lactalbumin are the molecular basis for allergenicity. In this paper, the effects of different lengths sugar chains on the structure and allergenicity of allergic epitopes in α-lactalbumin were investigated. The IgE linear epitopes of 13KDLKGYGGVSLPEW26 (13K-W26) were synthesized and glycated with glucose, maltose, maltotriose and maltopentaose. Then the structural changes were analyzed by spectroscopy and chromatography. Cellular assays and ELISA were used to evaluate the histamine, interleukin-4 and interleukin-6 release ability of KU812 cells and the IgE binding ability. The results showed that 13K-W26 was glycated by different lengths sugar chains significantly decreased the free amino content and changed the fluorescence intensity and UV absorption intensity, and decreased the IgE binding ability and the release ability of histamine, interleukin-4 and interleukin-6 in KU812 cells. Therefore, different lengths of sugar chains can change the structure of 13K-W26, and reduce the allergenicity. The order was maltopentaose>maltotriose>maltose>glucose. In conclusion, the sugar chains could mask the linear epitopes 13K-W26 of α-lactalbumin, the sugar chains with longer length had stronger masking effects on epitopes, the better the effect of reducing the allergenicity.

Keywords

• α-lactalbumin
• ige linear epitopes
• glycation
• allergenicity