Identification of an immunodominant region of the major house dust mite allergen Der p 2 presented by common human leucocyte antigen alleles.

BACKGROUND: Better understanding of the relevance of the immune response to common environmental allergens, such as the major house dust mite (HDM) allergen Der p 2, requires characterization of constituent T-cell epitopes. AIM: To identify CD4(+) T-cell epitopes within Der p 2 recognized by commonly expressed human leucocyte antigen (HLA) alleles. METHODS: HLA-blocking antibodies, peptide pools and truncations were used in ELISpot assays to establish restricted T-cell epitopes. RESULTS: People with and without atopic dermatitis have detectable Der p 2-specific T cells in the peripheral blood, which can proliferate in response to Der p 2 peptides. Interleukin-4-specific responses, both ex vivo and cultured to Der p 2 peptides, had a significant positive correlation with HDM-specific serum IgE. Within one pool of Der p 2 peptides, the 20mer D11 was found to induce multiple responses restricted through several alleles, including HLA-DPB1*0401 and HLA-DRB1*01. CONCLUSIONS: We have identified an immunogenic region of Der p 2 presented by common HLA class II alleles, including the most commonly expressed HLA allele DPB1*0401. Identification of such epitopes may be of future value in peptide immunotherapeutic approaches.