What makes an allergen?

Abstract

SummaryAllergic diseases are an immune disorder reacting to certain type of allergen(s). Remarkably only a small number of proteins of the plant and animal proteome act as allergens. Therefore, allergens have been clustered according to their common structural, biochemical and functional features. Evidence has accumulated that some allergens possess intrinsic adjuvant properties to stimulate the innate immunity. The adjuvant properties appear to contribute to the allergenicity of the respective proteins, namely the ability to cause allergic sensitization in susceptible subjects or allergic reactions in sensitized individuals. Here, we discuss how allergens interact with the innate immune cells, in particular dendritic cells and epithelial cells, via binding to pattern recognition receptors, exhibiting proteolytic activities and/or inducting type 2 innate lymphoid cells (ILC2), thereby contributing to the sensitization and development of allergic diseases.

Glycation of the Major Milk Allergen β‐Lactoglobulin Changes Its Allergenicity by Alterations in Cellular Uptake and Degradation

“…To execute their role, BMDCs are equipped with a full array of specialized receptors, including pattern‐recognition receptors (PRRs) such as toll‐like receptors (TLRs), C‐type lectins (CTLs), and SRs. Literature suggests that some allergens interact with PRR and thereby stimulate innate and adaptive responses . Considering their role in recognizing glycated products, we selectively blocked SRs and RAGE and found that SRs were responsible for the uptake of both native and glycated BLG.…”

Air Pollution and Climate Change Effects on Allergies in the Anthropocene: Abundance, Interaction, and Modification of Allergens and Adjuvants

“…8,84,103,105−109 Prominent examples are major allergens of birch pollen (Bet v 1), timothy grass pollen (Phl p 1), ragweed ( Ambrosia , Amb a 1), molds ( Alternaria alternata , Alt a 1, Cladosporium herbarum , Cla h 1, Aspergillus fumigatus , Asp f 1), and dust mites (Der p 1). 4,139,140 Besides allergens, also adjuvants and their interaction with the immune system play a critical role in the development of allergies.…”

Investigation of inflammatory and allergic responses to common mold species: Results from in vitro experiments, from a mouse model of asthma, and from a group of asthmatic patients

“…Various signaling pathways, characterized by the secretion of IL‐25, IL‐33, and the activation of different innate immune cells, contribute to generate a pro‐T‐helper 2 environment in the lungs. This ultimately leads to the activation of nonprotective allergen‐specific cells predominantly secreting characteristic Th2 cytokines such as IL‐4, IL‐5, and IL‐13 . These cytokines induce IgE production, cause eosinophilia, stimulate mast cells, promote leukocytosis, and provoke airway hyper reactivity.…”

“…This ultimately leads to the activation of nonprotective allergen-specific cells predominantly secreting characteristic Th2 cytokines such as IL-4, IL-5, and IL-13. 10,11 These cytokines induce IgE production, cause eosinophilia, stimulate mast cells, promote leukocytosis, and provoke airway hyper reactivity. This immune activation in asthma patients leads to repeated attacks of breathlessness, cough, and wheeze occurring secondary to broncho-constriction in the setting of airway hyper-responsiveness, mucus hyper-secretion, and airway remodeling.…”