Hormonal influence on antimicrobial peptide synthesis by fat body cells of a blowfly, Calliphora vicina R.-D. (Diptera, Calliphoridae)

The mechanism of septic induction of antimicrobial peptide synthesis in insects is well reported in current papers. On the contrary, there is little data on aseptic, particularly hormonal, regulation of immune defense. Insect neuroendocrinology traditionally considers hormones as regulators of development and reproduction, focusing less attention on their role in regulation of defense reactions. In the present study, the direct influence of ecdysones, adipokinetic hormone, and biogenic amines on antimicrobial peptide synthesis in isolated fat body cells of Calliphora vicina was studied. According to the results, low concentrations of α- and β-ecdysones and high doses of adipokinetic hormone and octopamine can stimulate the fat body activity in vitro. Thus, these hormones are key mediators of the adaptive syndrome, hormonal activation of endogenic antibiotic synthesis which probably takes place in response to extreme stimuli.