Fig. 3 | Mucosal Immunology

Fig. 3

From: Antigen-specific regulatory T-cell responses against aeroantigens and their role in allergy

Fig. 3

Stable and metastable states of tolerance against aeroantigens. a Particle-associated antigens generate a robust Treg response. This is a stable state of tolerance since Tregs actively prevent generation of Th2 responses. Soluble allergens are typically ignored by the immune system, due to their low antigen concentration in solution. Therefore, allergen-reactive cells remain in a naive state (ignorance). This represents a metastable state of tolerance, since naive T cells may still deviate into Th2 cells. Once primed, Th2 differentiation also represents a stable status. Whether established Th2 cells also prevent activation/expansion of naive Tregs is unclear. b SIT can delete pathogenic Th2 cells without de novo induction of Tregs. Depending on the availability of allergen-specific naive T cells, e.g., by thymic generation, this post-SIT status is also metastable. Thus, to achieve stable induction of tolerance in healthy or post-SIT allergics the generation of specific Treg responses against allergenic proteins should be a therapeutic target