Peanut allergen Ara h 2-specific T cells are activated via Ras-Erk MAP kinase pathway signalling and identified by CD154 expression.

Background. Peanut allergy is driven by peanut-specific Th2 cells. Ara h 2, a peanut 2S albumin, is one of the major peanut allergens. Methods. An Ara h 2-specific T cell line was generated from peanut sensitised C3H/HeJ mice and used to analyse allergen-induced cytokine secretion and activation of signalling molecules. Results. Peanut stimulated splenocytes from peanut sensitised mice had strong proliferation responses and highly elevated IL-4 secretion. The Ara h 2-specific T cells generated from sensitised mice were mainly CD4+ T helper cells with a Th2 cytokine profile. The expression of CD154 on the surface of these T cell clones was detected following Ara h 2 stimulation. Ara h 2 stimulation induced phosphorylation of ZAP-70 and Erk1/2 in the T cells. Conclusions. CD154 is a useful marker for identifying activated, allergen-specific T cells. The Ras-Erk mitogen-activated protein kinase pathway is involved in the activation of Ara h 2-specific Th2 cells. [ABSTRACT FROM AUTHOR]