Strong and frequent T-cell responses to the minor allergen Phl p 12 in Spanish patients IgE-sensitized to Profilins

Background Profilins are dominant pan-allergens known to cause cross-sensitization, leading to clinical symptoms such as the pollen food syndrome. This study aims to determine the T-cell response to Phl p 12 in profilin-sensitized patients, by measuring the prevalence, strength and cross-reactivity to clinically relevant profilins. Methods The release of Phl p allergens from pollen was determined by mass spectrometry and immunochemistry. T-cell responses, epitope mapping and cross-reactivity to profilins (Phl p 12, Ole e 2, Bet v 2, and Mal d 4) were measured in-vitro using PBMCs from 26 Spanish grass allergic donors IgE-sensitized to profilin. Cross-reactivity was addressed in-vivo using two different mouse strains (BALB/c and C3H). Results Phl p 12 and Phl p 1 are released from pollen simultaneously and in similar amounts. Both T cell response frequency (17/26 donors) and strength were comparable between Phl p 12 and Phl p 1. T-cell cross-reactivity to other profilins correlated with overall sequence homology, and two immunodominant epitope regions of Phl p 12 were identified. Data from mice immunized with Phl p 12 showed that cross-reactivity to Bet v 2 was mediated by conserved epitopes, and further influenced by additional genetic factors, likely to be MHC II. Conclusion The strength, prevalence and cross reactivity of T-cell responses towards Phl p 12 is comparable to the major allergen Phl p 1, which supports the hypothesis that T-cells to Phl p 12 can play an important role in development of allergic symptoms, such as those associated with the pollen-food syndrome. This article is protected by copyright. All rights reserved.