Characterization of the allergic T-cell response to Pru p 3, the nonspecific lipid transfer protein in peach

BackgroundPru p 3, the nonspecific lipid transfer protein from peach, is an important plant food allergen that frequently induces systemic reactions.ObjectiveWe sought to analyze the allergic T-cell response to Pru p 3.MethodsPBMCs from Italian and Spanish patients with peach allergy were stimulated with purified natural Pru p 3. Allergen-specific T-cell lines were used to identify T-cell epitopes of Pru p 3. Pru p 3–specific T-cell clones (TCCs) were analyzed for allergen-induced secretion of IL-4, IFN-γ, and IL-10 and expression of the integrin β7, a receptor critical for gut homing.ResultsNo difference in T-cell responses of Italian and Spanish patients was found. Among several T cell–activating regions, Pru p 313-27, Pru p 334-48, Pru p 343-57, and Pru p 361-75 were most frequently recognized in 18 Pru p 3–specific T-cell lines. The majority of 32 Pru p 3–specific TCCs belonged to the TH2 subset. In contrast to TCCs specific for other plant food and pollen allergens, only a limited number of Pru p 3–specific TCCs produced significant amounts of IL-10. The expression of integrin β7 on Pru p 3–specific TCCs was comparable with that observed on peanut-specific TCCs and higher compared with that seen in different pollen-specific TCCs.ConclusionThe T-cell response to Pru p 3 is dominated by TH2 cells presumably primed in the gut. The identification of relevant T cell–activating regions provides a basis for engineering hypoallergenic variants of Pru p 3 with less IgE binding and retained T-cell stimulatory capacity for safe immunotherapy of peach allergy.