Fig. 5
The role of DCs in type 2 inflammation and tolerance and tissue homeostasis. DCs are antigen-presenting cells that are able to process and integrate signals from the microenvironment. Upon exposure to proinflammatory stimuli, immature DCs develop into stimulatory DCs and promote an effector immune response by stimulating T-cell proliferation and shaping T-cell responses toward Th2 phenotypes via the indicated signals. DCs play a crucial role in antigen presentation to CD4 + T cells, shaping the subsequent immune response. The interaction between DCs and T cells can lead to different outcomes depending on the antigen dose and environmental signals. For example, a low allergen dose typically primes Th2 cells, promoting the allergic response. A high allergen dose, combined with tolerogenic signals such as vitamin D3 and RA, can induce tolerance. In a tolerogenic environment, DCs acquire regulatory functions that suppress T-cell activation and proliferation and provide signals for Treg differentiation and expansion. Treg and Breg cells support each other’s regulatory functions. These regulatory functions of DCs are key for maintaining immune tolerance and tissue homeostasis. Various factors contribute to this tolerogenic environment, including TSLP, RA, flavonoids, and SCFAs. Bas basophil, Breg regulatory B cells, DC dendritic cells, RA retinoic acid, SCFA short-chain fatty acid, Th2 T helper 2 cells, Treg regulatory T cells, TSLP thymic stromal lymphopoietin
