Allergy to birch pollen is common in the Northern Europe, North America, and in Japan, mainly in Hokkaido Island. Previously, we have reported the positive association of birch
pollen allergy in
HLA-DR9 antigen. We also have identified the recognition sites in 17kDa
protein (Bet v1), known as the major
allergen of birch pollen, by using T cell proliferation assay against the
trypsin digested materials of the 17kDa
protein. In this study, overlapping synthetic
peptides correspond to the Bet v1 sequences were used to investigate the specificity of T cell responses in two
HLA-DR9 positive patients. Three of the
epitopes, residues 35-52, 75-92, and 102-119, were recognized by T cells from both patients. These three
epitopes include
HLA-DR9 binding motifs. Then we established T cell clone specific to p75-92 residue. 78-89
peptide was the core sequence of the
epitope for the T cell clone contained the anchor residues characteristic to
HLA-DR9. Within the core sequence, five residues were identified as critical for recognition on the basis of inhibition of the T cell proliferative response against singly substituted analogue
peptides.