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. © 2011 British Association of Dermatologists.