Constructing a hybrid molecule with low capacity of IgE binding from Chenopodium album pollen allergens

Allergen specific immunotherapy is the only remedy to prevent the progression of allergic diseases. Nowadays, using of recombinant allergens with reduced IgE-binding capacity is an ideal tool for allergen immunotherapy. Therefore, in this study we focused on a hybrid molecule (HM) production with reduced IgE reactivity from Chenopodium album pollen allergens. By means of genetic engineering, a head to tail structure of the three allergens of the C. album pollen was designed. The resulting DNA construct coding for a 46kDa HM was inserted into an expression vector and expressed as hexahistidine tagged fusion protein in Escherichia coli. IgE reactivity of the HM was evaluated by western blotting, inhibition ELISA and in vivo skin prick test and its immunogenic property was tested by proliferation assay. The recombinant HM was expressed and purified by nickel-affinity chromatography. Comparison of the recombinant HM with a mixture of three recombinant allergens, as well as natural allergens in the whole C. album pollen extract via immunological experiments revealed that it has a much lower potential of IgE reactivity. Furthermore, in vivo skin prick tests showed that it has a significantly lower potency to induce cutaneous reactions than the mixture of recombinant wild type allergens and whole extract while, it had been preserved immunogenic properties. Our results have demonstrated that assembling three allergens of C. album in a hybrid molecule can reduce its IgE reactivity.