MULTIPLE T-CELL SPECIFICITIES FOR BET V-I, THE MAJOR BIRCH POLLEN ALLERGEN, WITHIN SINGLE INDIVIDUALS - STUDIES USING SPECIFIC T-CELL CLONES AND OVERLAPPING PEPTIDES

Twenty-five T cell clones specific for Bet v I were established from t he peripheral blood of two birch pollen-allergic patients. The T cell epitopes of these clones were mapped using dodecapeptides overlapping for 2 amino acids (neighbors share 10 residues) spanning the whole ami no acid sequence of the protein (159 amino acids). In total, 7 epitope s could be detected. One donor displayed 6 distinct T cell specificiti es for the Bet v I molecule in 14 T cell clones; for the other donor, 4 stimulating peptides for 11 clones could be identified. Two T cell e pitopes were recognized by both subjects. One of these might represent an immunodominant epitope located at amino acid position 77-92 of the Bet v I molecule, as in 13/25 T cell clones activation could be induc ed by this amino acid sequence. One T cell clone reacted with purified pollen-derived Bet v I, but neither with any peptide synthesized acco rding to a Bet v I-encoding cDNA nor with the respective recombinant p rotein. Upon stimulation with allergen, the majority of the clones (21 /24) revealed the TH0 or TH2 type of cytokine production (interleukin- 4 production), indicating their importance in the pathogenesis of the allergic disease.