Possibility for immunotherapy with long synthetic peptide of Bet v1

Abstract

In the peptide immunotherapy of allergy, although it is important to choose the T cell epitope on a consideration of the HLA type, application to all the HLA types is difficult. In this study, we synthesized long-chain synthetic peptides by dividing the sequence of Bet v1, the major white birch pollen allergen, into three peptides that overlapped by 10 amino acid residues for the immnunotherapy of white birch pollinosis. These peptides contain almost all the theoretically possible T cell epitopes and differ significantly from the three-dimensional structure of Bet v1; thus, the IgE epitopes are probably not included.
First, we evaluated the activation for patient basophil of the three synthetic peptides using the basophil activation test (BAT). All patients tested positive for Bet v1. However, they did not react to any of their peptides. Secondly, the ImmunoCAP-specific IgE inhibition assay showed that the binding avidity of IgE was low in all three peptides. Lastly, their potential of T-cell stimulatory capacities of the peptides were observed with the allergen-specific lymphocyte stimulation test (ALST). These results suggest that combinations of the three peptides may be used as antigenic epitopes, which could provide a safe and effective form of immunotherapy to treat white birch pollinosis.