Abstract
Septic injury induces in Drosophila the rapid and transient transcription of several genes encoding potent antimicrobial peptides. Significant structural and functional similarities exist between the injury-induced signalling cascades leading to antimicrobial peptide gene expression in Drosophila and cytokine-induced expression of mammalian acute-phase proteins. Here, the authors discuss their understanding of these pathways and their relationships to those found in mammalian cells. They also analyse non-self recognition and the role of blood cells in Drosophila host defence.