Carrier-bound nonallergenic Der p 2 peptides induce IgG antibodies blocking allergen-induced basophil activation in allergic patients

Background More than 90% of house dust mite‐allergic patients are sensitized to the major Dermatophagoides pteronyssinus allergen, Der p 2. The aim of this study was to develop and characterize an allergy vaccine based on carrier‐bound Der p 2 peptides, which should allow reducing IgE‐ and T‐cell‐mediated side‐effects during specific immunotherapy (SIT). Methods Five Der p 2 peptides (P1–P5) were synthesized and analyzed regarding IgE reactivity and allergenic activity. Lymphoproliferative and cytokine responses induced with Der p 2 and Der p 2 peptides were determined in peripheral blood mononuclear cells from mite‐allergic patients. Der p 2‐specific IgG antibodies induced with carrier‐bound Der p 2 peptides in mice and rabbits were tested for their capacity to inhibit IgE binding and basophil activation in allergic patients. Results Of five overlapping peptides (P1–P5) covering the Der p 2 sequence, two peptides (P2 and P4) were identified, which showed no relevant IgE reactivity, allergenic activity, and induced lower Der p 2‐specific T‐cell activation than Der p 2. However, when coupled to a carrier, P2 and P4 induced Der p 2‐specific IgG antibodies in animals, which inhibited allergic patients' IgE binding to the allergen and allergen‐induced basophil activation similar as antibodies induced with Der p 2. Conclusions Carrier‐bound Der p 2 peptides should allow avoiding IgE‐mediated side‐effects, and because of their low potential to activate allergen‐specific T cells, they may reduce late‐phase side‐effects during SIT. Further, these peptides may be also useful for prophylactic vaccination.