CD4+ T cells from allergic individuals recognize epitopes from the common household allergens Der p 1 and Alt a 1 and secrete Th2 cytokines (36.8)

Abstract

Abstract Allergy is initiated by adaptive Th2-mediated responses; however, little is known about CD4+ T cell epitopes within many common allergens. The objectives of this study were to utilize MHC class II tetramers to identify CD4+ T cell epitopes within household allergens and to isolate allergen reactive T cells for further phenotypic analysis. PBMCs were isolated from the blood of subjects with dust mite and mold (Alternaria) allergies and from non-allergic control subjects, and CD4+ T cells were assayed for responses to sets of allergen-derived peptides. Dust mite allergen epitopes within the Der p 1 protein were mapped for DRB1*0301, *0401, *0701, and *1501 individuals; Alternaria allergen epitopes within the Alt a 1 protein were mapped for DRB1*0301, *0401, *0701, and *1101 individuals. Tetramer-positive responses to allergen epitopes were frequently seen in CD4+ T cells from allergic subjects. A high proportion of tetramer-positive cells from allergic individuals secreted IL-5 while TNF-α, IL-10 and IFN-γ secretion occurred less frequently, indicating that the cytokine response to these allergens is predominantly Th2 polarized. Identification of CD4+ T cell epitopes and characterization of T cell responses to allergens will further our understanding of allergic disease and may prove helpful to improve specific immunotherapy.