Context matters: TH2 polarization resulting from pollen composition and not from protein-intrinsic allergenicity

[Swissallergy]

“Birch (Betula verrucosa) pollen is the main cause of spring pollinosis in the temperate climate zone of the Northern Hemisphere. Approximately 95% of birch pollen–allergic patients are sensitized to Bet v 1, the major birch pollen allergen.1

However, it is not known whether sensitization toward Bet v 1 results from its own intrinsic properties or from immunomodulatory pollen compounds codelivered with the allergen. Therefore, we investigated whether Bet v 1 or the pollen matrix is responsible for the activation of antigen-presenting cells and the subsequent TH2 polarization, relevant in the process of allergic sensitization. Because dendritic cells (DCs) are the most potent activators of adaptive immune responses, we sought to investigate their role in the process of allergic sensitization toward Bet v 1. For this purpose, the activation of murine bone marrow–derived dendritic cells (mBMDCs) as well as the maturation of human monocyte–derived dendritic cells was monitored in vitro.

Concerning the latter, PBMCs were isolated either from healthy, nonatopic donors or from atopic patients. Cells were stimulated either with recombinant Bet v 1.0101 (rBet v 1) produced in E coli or with an aqueous birch pollen extract (BPE). We analyzed whether DC activation is triggered by the costimulation of Toll-like receptor (TLR) 4 by LPS contaminations found in BPE, termed nLPS. Furthermore, we investigated the capacity of rBet v 1 and BPE to induce TH2 polarization using an in vivo sensitization model.
Full article: https://pubmed.ncbi.nlm.nih.gov/29782896/

[Auteur]

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