A naturally-processed universal T cell epitope is located within a conserved region of Der p 2: Implications for allergen sensitization and immunotherapy

Background: Major allergens could represent a 'port of entry' to allergen p olysensitization. The immunogenic properties of Der p 2 T cell epitopes wer e evaluated to test this hypothesis. Material and Methods: T cells were obt ained from regional lymph nodes of mice belonging to four different haploty pes and used in proliferation assays using Der p 2 or synthetic peptides. R esults: T cells from recombinant (r) Der p 2-immunized Balb/c mice (H-2(d)) proliferated to an immunodominant region encompassing residues 21-35, whic h also stimulates T cells of mice expressing three alternative haplotypes ( H-2(b), H-2(k) and H-2(S)), indicating the presence of a universal T cell e pitope. Epitope mapping identified Ile28 as a critical H-2-binding residue for all four different haplotypes. p21-35 presents a sequence homology with FIS, another universal T cell epitope. FIS priming boosts immune responses to distinct weak immunogens. Balb/c mice primed with p21-35 or FIS produce d stronger immune responses to transferrin upon administration of the latte r than unprimed mice. Besides, this procedure profoundly affected the overa ll B cell response to rDer p 2. Conclusion:An immunodominant T cell epitope of Der p 2 behaves as a universal epitope and enhances responses to relate d and unrelated coadministered antigens. These findings have implications f or the understanding of allergen polysensitization and for immunotherapy. C opyright (C) 2001 S. Karger AG, Basel.