FIGURE 7.

Graphical summary of the protective effect of PepN on allergic asthma. In allergic asthma, PepN inhibited the production of epithelium‐derived immature dendritic cell (DCs) chemokine CCL20, which reduced the recruitment of lung CD11b⁺ DCs. The decrease in lung CD11b⁺ DCs recruitment led to the decrease in the uptake of lung allergen OVA; therefore, the Th2 immune response (increased Th2 cytokines IL‐4, IL‐5, IL‐13, enhanced IgE level, eosinophilia and mucus hypersecretion) initiated by CD11b⁺ DCs was reduced. Besides, PepN also inhibited the production of epithelium‐derived IL‐33, which reduced the number of lung type 2 innate lymphoid cell (ILC2s). The reduced ILC2s may directly reduce the Th2 immune response by reducing the production of Th2 cytokines IL‐4, IL‐5 and IL‐13 (dashed line)