rational design of hypoallergenic vaccines: blocking ige-binding to polcalcin using allergen-specific igg antibodies

Chenopodium album polcalcin (che a 3) is characterized as a major cause of cross-reactivity inallergic patients to the chenopodiaceae family. therefore, the present study was conducted to develop a hypoallergenic che a 3 derivatives as the candidate vaccine for type 1 allergy. four derivatives were generated from che a 3. the first was a mosaic peptide derivative computationally identified in che a 3 which was coupled to keyhole limpet hemocyanin (klh). the second one was a mutant che a 3, and the other two derivatives included n- and c-terminal halves of che a 3 that both coupled to klh. the ige-binding capacity of che a 3 and its derivatives and also their ability to induce there combinant che a 3 (rche a 3)-specific igg antibody, were determined using the enzyme-linked immune sorbent assay (elisa). moreover, the lymphopro liferative capacity of rche a 3 or its derivatives and their pro-inflammatory cytokine response interleukin (il)-5 and il- 13 were measured in the human peripheral blood mononuclear cells (pbmcs). among all derivatives, the n-terminal half peptide and mosaic peptide exhibited the lowest igebinding capacity. in addition, in comparison to other antigens, klh-coupled mosaic peptide induced the highest level of the recombinant che a 3 (rche a 3)-specific igg antibody and ther che a 3 specific-blocking igg antibody in mice. moreover, the mosaic peptide lacked lymphopro liferative capacity and down-regulated expression of pro-allergic il-5 and il-13 cytokines.therefore, a peptide-carrier fusion vaccine, composed of the b-cell epitope coupled to the carrier, could be considered as one of the promising hypoallergenic vaccines to treat patients with allergy to low molecular weight allergens such as che a 3.