Enhanced Cysteinyl-Leukotriene Type 1 Receptor Expression in T Cells from House Dust Mite-Allergic Individuals following Stimulation with Der p

In order to determine the potential for allergen to modulate T cell expression of the CysLT(1) receptor and responsiveness to leukotrienes, peripheral blood mononuclear cells from house dust mite-allergic or nonallergic individuals were incubated with D. pteronyssinus allergen (Der p). Baseline CysLT(1) expression was similar in both groups of donors, but Der p significantly enhanced CysLT(1) expression in CD4(+) and CD8(+) T cells of only allergic individuals and induced enhanced responsiveness of CD4(+) T cells to LTD(4) in terms of calcium mobilisation. This effect was prevented by the CysLT(1) antagonist MK571. Der p also induced IL-4 and IL-10 production, and neutralizing antibody to IL-4 prevented both the enhanced CysLT(1) expression and the enhanced responsiveness of T cells to LTD(4) induced by Der p. In allergic individuals, Der p also induced T cell proliferation and a Th2-biased phenotype. Our data suggest that, in allergen-sensitized individuals, exposure to allergen can enhance T cell expression of CysLT(1) receptors through a mechanism involving IL-4 production. This, in turn, would induce CD4(+) T cell responsiveness to cysteinyl-leukotrienes and Th2 cell activation.