A diagram illustrating the design and activation of Chimeric Allergen Receptors (CAlleR) and their effects in sensitized mice. The design process of CAlleR involves isolating anti-Bet v1 antibodies from a birch allergic donor, and creating anti-Bet v1 CAlleR. CAlleR activation mechanisms through allergen cross-presentation include soluble allergen presentation through non-competitive antibodies, leading to immune complex stabilization by Fc gamma receptor (FcγR) on antigen-presenting cells (APC). Adoptive transfer of CAlleR Tregs in sensitized mice shows preferential migration to allergen-exposed organs like the lung and mediastinal lymph node, and downmodulating allergic airway inflammation (AAI) compared to control CAR Tregs.