Fig. 8. The tissue damage response (TDR).

Schematic model depicting the TDR. Tissues damaged by tumors or wounding trigger an immune response in blood cells. The TDR involves at least two aspects. First, the damaged tissue elevates JNK activity and secretes JAK/STAT-activating cytokines (Upd, Upd2, and Upd3). JAK/STAT cytokines released from the damaged tissue activate JAK/STAT signaling in hemocytes and the fat body, which in turn activates more cytokine expression, thus amplifying the response and inducing hemocyte proliferation. Second, hemocytes adhere to the damaged region as a consequence of BM disruption. The TDR restricts tumor growth and could aid defense against infection following wounding.