Figure 1. Wound healing macrophage activation.

(a) Injury by cuts, chemicals (CCl₄ and bleomycin), helminths or burn injury causes a breach in barrier. (b) The wound healing response is initiated by dying cells which release cytokines (TSLP, IL-25, and IL-33) that activate Th2 cytokine (IL-4/IL-13) producing cells (blue). Innate cells such as neutrophils (orange) are also recruited to kill invading pathogens, and apoptose once the challenge is resolved. (c) M2 macrophages (left) are activated by the Th2 cytokines. Equally important is the activation of resolving macrophages (right) which are activated by phagocytosis of the apoptotic cells resulting from the inflammation. Rather than distinct subsets, both M2 and resolving macrophages represent a continuum of macrophage activation that are influenced by both Th2 cytokines and apoptotic cells.