This family consists of the metchnikowin family of antimicrobial peptides from Drosophila. Metchnikowin is a proline-rich peptide whose expression is immune-inducible. Induction of the metchnikowin gene expression can be mediated either by the TOLL pathway or by the imd gene product. The metchnikowin peptide is unique among the Drosophila antimicrobial peptides in that it is active against both bacteria and fungi [PMID: 9600835].