Adenosine facilitates the angiogenic switch by macrophages. Upon bacterial infection, macrophages respond by the secretion of leukocyte recruiting mediators. Macrophages also secrete cytokines that will initiate a Type 1 response by the adaptive immune system. This inflammatory response leads to increased tissue damage and hypoxia as the bacterial infection is resolved (green). Extracellular adenosine concentrations increase as a result of cellular damage and hypoxia (grey). Adenosine facilitates the angiogenic switch by inhibiting IL-12 and enhancing VEGF and IL-10 production by macrophages (dark pink).