The development of a candidate of desensitization vaccines against Der f 2 nearly without IgE-binding activity

Considering the important role of Der f 2 in house dust mites mediating allergic diseases and allergic adverse effects during allergen-specific immunotherapy (AIT), we intend to develop a candidate of desensitization vaccines against Der f 2 without allergenicity. According to the reported immunoglobulin E (IgE)-binding B and T cell epitopes of Der f 2, four candidates of desensitization vaccines against Der f 2 were developed. Recombinant wild-type Der f 2 (rWt-Der f 2) preserved conformational and linear IgE-binding B epitopes. rWt-Der f 2 linearized by reduction and alkylation reactions (rWt-Der f 2 (red/alk)) and recombinant modified-type Der f 2 (rMt-Der f 2) were developed via destroying conformational and linear IgE-binding B epitopes respectively. rMt-Der f 2 linearized by reduction and alkylation reactions (rMt-Der f 2 (red/alk)) was developed by destroying conformational and linear IgE-binding B epitopes. T cell epitopes of 4 candidates were preserved. The change of their IgE-binding activity was determined by enzyme linked immunosorbent assay (ELISA), western blot and inhibition ELISA. Compared with rWt-Der f 2, the IgE-binding activity of rWt-Der f 2 (red/alk), rMt-Der f 2 and rMt-Der f 2 (red/alk) all decreased, which was consistent with the result of western blot. The IgE-binding activity of rMt-Der f 2 and rMt-Der f 2 (red/alk) was not significantly different (P = 0.0863 > 0.05), which was comparable to that of their corresponding negative controls (P = 0.3488 and 0.4459, both > 0.05). The result of inhibition ELISA also showed that their IgE-binding activity decreased, and rMt-Der f 2 (red/alk) was the lowest. Conclusively, we developed the candidate of desensitization vaccines against Der f 2, rMt-Der f 2 or rMt-Der f 2 (red/alk), nearly without allergenicity, which would potentially prevent HDM allergic patients from allergic adverse effects caused by AIT.