Inactivation of frog virus 3 and channel catfish virus by esculentin-2P and ranatuerin-2P, two antimicrobial peptides isolated from frog skin

While it is clear that some amphibian populations have recently experienced precipitous declines, the causes of those die-offs are complex and likely involve multiple variables. One theory suggests that environmental factors may trigger events that result in depressed immune function and increased s usceptibility to infectious disease. Here we examine one aspect of innate i mmunity in amphibians and show that esculentin-2P (E2P) and ranatuerin-2P ( R2P), two antimicrobial peptides isolated from Rana pipiens, inactivate fro g virus 3, a potentially pathogenic iridovirus infecting anurans, and chann el catfish herpesvirus. In contrast to mammalian antimicrobial peptides, E2 P and R2P act within minutes, at temperatures as low as 0 degreesC, to inhi bit viral infectivity. Moreover, these compounds appear to inactivate the v irus directly and do not act by inhibiting replication in infected cells. T his is the first report linking amphibian antimicrobial peptides with prote ction from an amphibian viral pathogen and suggests that these compounds ma y play a role in maintaining amphibian health. (C) 2001 Academic Press.