Possesses antifungal activity and is active against a relatively broad spectrum of filamentous fungi (PubMed:8808632, PubMed:12872120). It inhibits spore germination at high concentrations and at low concentrations delays growth of hyphae which subsequently exhibit abnormal morphology (PubMed:7806546). Spz C-106 in the hemolymph controls expression of the antifungal peptide by acting as a ligand of Tl and inducing an intracellular signaling pathway (PubMed:8808632). Part of a psh-dependent Toll pathway, which may function in activating the systematic immune response in response to localized melanization of the tracheal system (PubMed:18854145). Hemolymph (at protein level) (PubMed:9736738). Synthesized in the fat body and is secreted into the blood (PubMed:9736738). In larvae, expressed in the visceral branches and posterior spiracles of the trachea (PubMed:22022271). By bacterial infection (at protein level) (PubMed:9736738). In hemolymph 6 hours after bacterial infection, levels of expression increase for first 24 hours and persist for the following three weeks (at protein level) (PubMed:9736738). Up-regulated by septic injury caused by the Gram-positive bacterium M.luteus and the fungus C.albicans, and by M.luteus or E.faecalis-derived peptidoglycans and by B.subtilis or A.oryzae proteases (PubMed:19590012). Up-regulated by Gram-negative bacteria in the respiratory epithelium (PubMed:22022271). Up-regulated in the trachea and fat body in response to tracheal melanization, either by spontaneous melanization or melanization resulting from infection by bacteria (E.coli and M.luteus) or the fungus B.bassiana (PubMed:18854145).