Abstract

Molecular allergology research has provided valuable information on the structure and function of single allergenic molecules. There are several allergens in food and inhalant allergen sources that are able to interact with lipid ligands via different structural features: hydrophobic pockets, hydrophobic cavities, or specialized domains. For only a few of these allergens information on their associated ligands is already available. Several of the allergens are clinically relevant, so that it is highly probable that the individual structural features with which they interact with lipids have a direct effect on their allergenic potential, and thus on allergy development. There is some evidence for a protective effect of lipids delaying the enzymatic digestion of the peanut (Arachis hypogaea) allergen Ara h 8 (hydrophobic pocket), probably allowing this molecule to get to the intestinal immune system intact (sensitization). Oleosins from different food allergen sources are part of lipid storage organelles and potential marker allergens for the severity of the allergic reaction. House dust mite (HDM), is more often associated with allergic asthma than other sources of inhalant allergens. In particular, lipid-associated allergens from Dermatophagoides pteronyssinus which are Der p 2, Der p 5, Der p 7, Der p 13, Der p 14, and Der p 21 have been reported to be associated with severe allergic reactions and respiratory symptoms such as asthma. The exact mechanism of interaction of these allergens with lipids still has to be elucidated. Apart from single allergens glycolipids have been shown to directly induce allergic inflammation. Several—in parts conflicting—data exist on the lipid (and allergen) and toll-like receptor interactions. For only few single allergens mechanistic studies were performed on their interaction with the air-liquid interface of the lungs, in particular with the surfactant components SP-A and SP-D. The increasing knowledge on protein-lipid-interaction for lipophilic and hydrophobic food and inhalant allergens on the basis of their particular structure, of their capacity to be integral part of membranes (like the oleosins), and their ability to interact with membranes, surfactant components, and transport lipids (like the lipid transfer proteins) are essential to eventually clarify allergy and asthma development.

Highlights

  • In recent decades, allergies have become the number one chronic disease in many parts of the world affecting up to 30% of the population in each country [1]

  • The association with lipids has been described for the allergen families Bet v 1-superfamily, lipid transfer proteins, 2S albumins, 7 and 11S globulins, oleosins, lipocalins, apolipophorins, and the mite allergen groups 2, 5, and 7

  • Some lipids change the tertiary structure of proteins so that allergenic epitopes are exposed to IgE antibodies

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Summary

INTRODUCTION

Allergies have become the number one chronic disease in many parts of the world affecting up to 30% of the population in each country [1]. Over the last years the view on lipid-associated allergens has changed, in particular by the discovery of the oleosins, a unique group of water-insoluble membrane proteins They are absent from diagnostic extracts but have been shown to be potential marker allergens for the severity of the allergic reaction to food [2, 3, 13]. These findings have directed our research to the question of the effect of lipids and their association with lipophilic allergens in the context of allergic diseases (see Figure 1). The association with lipids has been described for the allergen families Bet v 1-superfamily, lipid transfer proteins, 2S albumins, 7 and 11S globulins, oleosins, lipocalins, apolipophorins, and the mite allergen groups 2, 5, and 7

Resulting effects
Binds fatty acids in inner hydrophobic cavity
Delayed enzymatic digestion
Potentially binds lipids from house dust mite
FOOD ALLERGEN SOURCES
MAMMALIAN ALLERGENS
Findings
ARTHROPOD ALLERGENS
Full Text
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