Amphibian innate immune mediators protect against human Influenza strains

Abstract Frogs and toads are incredible reservoirs of biologically active peptides. Amphibians secrete host defense peptides from their skin as part of their innate immune response. This ancient response acts to protect the amphibians against microbes. The quantity and scope of these secreted peptides dwarfs mammalian analogues, accounting for a substantial portion of all known host defense peptides. The non-invasive and non-harmful methods for frog peptide collection, in tandem with the abundance and breadth of these peptides, makes them excellent choices for novel peptide drug therapies. Studies have shown that these peptides can effectively neutralize enveloped viruses, mycobacteria, gram-negative and gram-positive bacteria, fungi, and even cancerous or transformed cells. Because of the nature of antimicrobial peptides, often targeting the most critical, conserved aspects of a micro-organism, they may prove a vital alternative to conventional drugs plagued by pathogen resistance. Given this untapped potential for anti-viral therapies, we assessed novel host defense peptides from the skin of the Indian fungoid frog, Hylarana malabarica. During our analysis, we isolated several peptides from H. malabarica that show anti-viral activity against human influenza viruses. Our studies indicate that peptides from H. malabarica demonstrate anti-influenza activity in vitro, and also show potential as an anti-viral therapy in vivo.