Aryl hydrocarbon receptor activation affects the dendritic cell phenotype and function during allergic sensitization

Area of Science:

• Immunology
• Toxicology
• Allergy Research

Background:

• Aryl hydrocarbon receptor (AhR) activation by dioxin (TCDD) is known to suppress peanut sensitization via T cell modulation.
• The specific impact of AhR activation on dendritic cells (DCs) in allergic responses remains uninvestigated.

Purpose of the Study:

• To investigate the effects of AhR activation on dendritic cell phenotype and function in vivo.
• To assess the capacity of AhR-modulated DCs to stimulate allergen-specific T cells and induce regulatory T cells (Tregs).

Main Methods:

• C3H/HeOuJ mice were treated with TCDD and sensitized to peanut extract (PE).
• Splenic and mesenteric lymph node (MLN) DCs were analyzed for phenotype and activation markers.
• PE-pulsed DCs were co-cultured with PE-specific CD4+ T cells to assess cytokine production and Treg induction.

Main Results:

• TCDD treatment significantly increased CD11c+CD103+ DCs in the spleen but decreased total and CD103+ DCs in MLNs.
• DC activation markers remained largely unaffected in both spleen and MLN.
• PE-pulsed splenic DCs from TCDD-treated mice suppressed key allergic cytokine production (IL-5, IL-13) by T cells, without inducing Tregs.

Conclusions:

• AhR activation influences DC populations and function, contributing to the suppression of food allergy initiation.
• The observed suppression of allergic responses is linked to altered DC-T cell interactions, rather than Treg induction.