Analysis of human T cell responses to the group II allergen of Dermatophagoides species: localization of major antigenic sites.

Abstract

IgE antibodies reactive with the group II allergens of Dermatophagoides species (house dust mite [HDM]) are a major component of the allergic immune response in HDM-allergic atopic individuals. Here we demonstrate, with the use of overlapping synthetic peptides of the group II allergen of Dermatophagoides pteronyssinus (Der p II), that polyclonal T cells isolated from the majority of atopic HDM-allergic individuals and healthy nonatopic control subjects respond to Der p II and that T-cell epitopes are present in all regions of the protein. From comparison of peptide-specific T-cell proliferation in both groups of individuals, it appears that together peptides 61-86 and 78-104 are the most frequently recognized (16 of 18 individuals). We also observed that nine of the 18 individuals responded to T-cell epitopes in the region 11-50, and with Der p II-reactive T-cell clones, three distinct T-cell epitopes were mapped within the sequence 11-35. Also, with the use of T-cell clones, two additional epitopes were identified at residues 81-96 and 91-101. These results suggest that T-cell epitopes located in these regions (11-50 and 61-104) are immunodominant. The value of this information in the potential application of Der p II peptides to desensitize HDM allergic responses is discussed.