6 research outputs found
The house dust mite allergen Der p 5 binds lipid ligands and stimulates airway epithelial cells through a TLR2âdependent pathway
Background:
Protein crystallographic studies suggest that the house dust mite (HDM) allergen Der p 5 potentially interacts with hydrophobic ligands. Der p 5, in association with its ligand(s), might therefore trigger innate immune signalling pathways in the airway epithelium and influence the initiation of the HDMâallergic response.
Objective:
We investigated the lipid binding propensities of recombinant (r)Der p 5 and characterized the signalling pathways triggered by the allergen in airway epithelial cells.
Methods:
rDer p 5 was produced in Pichia pastoris and characterized by mass spectrometry, multiâangle light scattering and circular dichroism. Its interactions with hydrophobic ligands were investigated in fluorescenceâbased lipid binding assays and inâsilico docking simulations. Innate immune signalling pathways triggered by rDer p 5 were investigated in airway epithelial cell activation assays in vitro.
Results:
Biophysical analysis showed that rDer p 5 was monomeric and adopted a similar αâhelixârich fold at both physiological and acidic pH. Spectrofluorimetry experiments showed that rDer p 5 is able to selectively bind lipid ligands, but only under mild acidic pH conditions. Computerâbased docking simulations identified potential binding sites for these ligands. This allergen, with putatively associated lipid(s), triggered the production of ILâ8 in respiratory epithelial cells through a TLR2â, NFâkBâ and MAPKâdependent signalling pathway.
Conclusions and Clinical Relevance:
Despite the fact that Der p 5 represents a HDM allergen of intermediate prevalence, our findings regarding its lipid binding and activation of TLR2 indicate that it could participate in the initiation of the HDMâallergic state