[en] Background: Der p 3 a trypsin-like protease is a Dermatophagoides pteronyssinus allergen which is synthesized in the mite under a zymogen form. The enzymatic activity of this allergen has been shown to enhance the inflammatory process of allergy. To date, there are a few studies that described the allergenicity and the IgE reactivity of the group 3 allergens, the allergenic properties of recombinant Der p 3 was also not characterized.
Methods: The autolysis of rDer p 3 and rDer p 3 S196A were analyzed by means of SDS-PAGE and enzymatic activity and their allergenicities by means of assays for IgE binding, IgE binding inhibition and basophiles mediator-release.
Results: 100% of the sera from allergic patients showed IgE reactivity to natural Der p 3 and recombinant form. However, the IgE binding to the Der p 3 was less 4 times than rDer p 1. The IgE binding to rDer p 3 S196A was higher than rDer p 3. These variations can be linked with the phenomen of autolysis and instability of Der p 3 during the ELISA test. The mediators release performed with RBL sensitized with sera from allergic patients and stimulated with rDer p3, rDer p 3 S196A and natural Der p 3 were similar and lower than Der p 1 for concentration < 10 ng/ml.
Conclusions: recombinant mature Der p 3 retained overall identity to its natural form in terms of structure and allergenicity. The instability and autolysis of Der p 3 drastically influence its IgE binding capacity. These results can be explain the considerable variations with the frequencies reactivity (16-100%) of natural Der p 3. The RBL assays demonstrated that the allergenicity of rDer p 3 is similar to rDer p 1 for the concentrations >10 ng /ml.
