Tissue‐specific antigen‐presenting cells contribute to distinct phenotypes of allergy

Abstract

Antigen presenting cells (APCs) are critical cells bridging innate and adaptive immune responses by taking up, processing, and presenting antigens to naïve T cells. At steady state, APCs thus control both tissue homeostasis and the induction of tolerance immune responses. In allergies however, APCs drive a Th2‐biased immune response that is directed against otherwise harmless antigens from the environment. The main types of APCs involved in the induction of allergy are dendritic cells, monocytes and macrophages. However, these cell types can be further divided into local, tissue‐specific populations that differ in their phenotype, migratory capacity, T cell activating potential, and production of effector molecules. Understanding if distinct populations of APCs contribute to either tissue‐specific immune tolerance, allergen sensitization, or allergic inflammation will allow us to better understand disease pathology and develop targeted treatment options for different stages of disease. Therefore, this review describes the main characteristics, phenotypes, and effector molecules of the APCs involved in the induction of allergen‐specific Th2 responses in important barrier sites, such as the skin, nose, lung, and gastrointestinal tract. Furthermore, we highlight open questions that remain to be addressed to fully understand the contribution of different APCs to allergic disease.This article is protected by copyright. All rights reserved

Circulating immunome fingerprint in eosinophilic esophagitis is associated with clinical response to proton pump inhibitor treatment

“…When we studied these two groups PrePPI intake, non-responding patients had lower levels of pDCs, classical monocytes and an unknown myeloid APC cluster, but higher levels of non-memory B cells, mature NK cells and central memory CD4 + T-cells. These results might indicate an increased antigen presentation activity, since they have decreased numbers of circulating APC populations, which are key in homeostasis and allergy response (38). Indeed, latest results from our group (39) reinforce this hypothesis showing that nonresponding patients' esophageal proteomic profile when compared to responding patients (both PrePPI), have increased levels of proteins associated with antigen presentation.…”

Circulating immunome fingerprint in eosinophilic esophagitis is associated with clinical response to proton pump inhibitor treatment

“…When we studied these two groups PrePPI intake, non-responding patients had lower levels of pDCs, classical monocytes and an unknown myeloid APC cluster, but higher levels of non-memory B cells, mature NK cells and central memory CD4 + T-cells. These results might indicate an increased antigen presentation activity, since they have decreased numbers of circulating APC populations, which are key in homeostasis and allergy response 34 . Indeed, latest results from our group 35 reinforce this hypothesis showing that non-responding patients’ esophageal proteomic profile when compared to responding patients (both PrePPI), have increased levels of proteins associated with antigen presentation.…”

A randomized, double‐blind, placebo‐controlled trial with mannan‐conjugated birch pollen allergoids

“…11 Among these, the polymannose backbone (mannan) from Saccharomyces cerevisiae was suggested as strategy to increase capture/presentation of allergens by dendritic cells (DCs). 12,13 DC subtypes play essential roles during sensitization and effector phases of allergic inflammations, 14,15 and changed levels of DC subtypes upon AIT have been reported. 16 With glutaraldehyde as a cross-linker, allergoids coupled to nonoxidized mannan target DCs through C-type lectin receptors.…”