Birch pollen allergen Bet v 1 binds to and is transported through conjunctival epithelium in allergic patients

Abstract

Background:  Previous work in type‐I pollen allergies has mainly focused on lymphocytes and immune responses. Here, we begin to analyse with a systems biology view the differences in conjunctival epithelium obtained from healthy and allergic subjects.Methods:  Transcriptomics analysis combined with light and electron microscopic analysis of birch pollen allergen Bet v 1 located within conjunctival epithelial cells and tissues from birch allergic subjects and healthy controls was carried out.Results:  Bet v 1 pollen allergen bound to conjunctival epithelial cells within minutes after the exposure even during the nonsymptomatic winter season only in allergic, but not in healthy individuals. Light‐ and electron microscopy showed that Bet v 1 was transported through the epithelium within lipid rafts/caveolae and reached mast cells only in allergic patients, but not in healthy individuals. Transcriptomics yielded 22 putative receptors expressed at higher levels in allergic epithelium compared with healthy specimens. A literature search indicated that out of these receptors, eight (i.e. 37%) were associated with lipid rafts/caveolae, which suggested again that Bet v 1 transport is lipid raft/caveola‐dependent.Conclusions:  We show a clear difference in the binding and uptake of Bet v 1 allergen by conjunctival epithelial cells in allergic vs healthy subjects and several putative lipid raft/caveolar receptors were identified, which could mediate or be co‐transported with this entry. The application of discovery driven methodologies on human conjunctival epithelial cells and tissues can provide new hypotheses worth a further analysis to the molecular mechanisms of a complex multifactorial disease such as type‐I birch pollen allergy.