Effect of XXXX Polymorphisms of House Dust Mite Der p 2 Variants on Allergic Sensitization.

@entity7130 @entity19 @entity38263 @entity375 @entity3689
PURPOSE: The sequence variations of the Der p 2 allergen of @entity7130 diverge along 2 pathways with particular @entity3689 substitutions at positions 40,47,111, and 114. The environmental prevalence and IgE binding to Der p 2 variants differ among regions. To compare IgE binding to Der p 2 variants between sera from Bangkok, Thailand and Perth, Western Australia with different variants and to determine the variant-specificity of antibodies induced by vaccination with recombinant variants. METHODS: The structures of recombinant variants produced in @entity375 were compared by circular dichroism and @entity38263 staining of their lipid-binding cavity. Sera from subjects in Bangkok and Perth where different variants are found were compared by the affinity (IC      ) of IgE cross-reactivity to different variants and by direct IgE binding. @entity19 were immunized with the variants Der p 2.0101 and Der p 2.0110, and their IgG binding to Der p 2.0103, 2.0104, and 2.0109 was measured. RESULTS: The secondary structures of the recombinant variants resembled the natural allergen but with differences in ANS binding. The IC       of Der p 2.0101 required 7-fold higher concentrations to inhibit IgE binding to the high-IgE-binding Der p 2.0104 than for homologous inhibition in sera from Bangkok where it is absent, while in sera from Perth that have both variants the IC       was the same and low. Reciprocal results were obtained for Der p 2.0110 not found in Perth. Direct binding revealed that Der p 2.0104 was best for detecting IgE in both regions, followed by Der p 2.0101 with binding to other variants showing larger differences. Mouse anti-Der p 2.0101 antibodies had a high affinity of cross-reactivity but bound poorly to other variants. CONCLUSIONS: The affinity of IgE antibody cross-reactivity, the direct IgE binding, and the specificities of antibodies induced by vaccination show that measures of allergic sensitization and therapeutic strategies could be optimized with knowledge of Der p 2 variants.
