Effect of Cecropin B and a Synthetic Analogue on Propagation of Fish Viruses In Vitro

Abstract

Cecropins and other natural antimicrobial peptides are widely distributed in animals from insects to mammals. These proteins have been shown to be major constituents of the innate immune systems of animals for nonspecific defense of the host against various bacteria and parasites. Therefore, exploitation of this natural innate defense system may lead to the development of effective methods for protecting fish from invasion by microbial pathogens. Recently, we have demonstrated that the introduction of cecropin transgenes into Japanese medaka (Oryzias latipes) conferred resistance to infection by fish bacterial pathogens. Aside from a few reports documenting the antiviral effect of antimicrobial peptides including cecropins against mammalian viruses, there is no evidence for the effect of these peptides against fish viruses. In this article we present results of in vitro characterization of native cecropin B and a synthetic analogue, CF17, against several important fish viral pathogens--namely, infectious hematopoietic necrosis virus (IHNV), viral hemorrhagic septicemia virus (VHSV), snakehead rhabdovirus (SHRV), and infectious pancreatic necrosis virus (IPNV). Upon coincubation of these peptides and viruses, the viral titers yielded in fish cells were reduced from several fold to 104-fold. Direct disruption of the viral envelope and disintegration of the viral capsids may be involved in the inhibition of viral replication by the peptides. Results of our studies demonstrate the potential of manipulating antimicrobial peptide genes by transgenesis to combat viral infection in fish.

Antimicrobial peptides (AMP) with antiviral activity against fish nodavirus

“…The reported antiviral mechanisms of other AMPs are diversified. For example, cecropin B is demonstrated to inhibit IHNV, VHSV, SHRV and IPNV by direct disruption of viral envelope and disintegration of viral capsids [24]; human a-defensins HD5 inhibits BK virus, by agglutinating its virions and forming aggregates [39]; some defensins are shown to act like lectins, binding to both HIV glycoprotein gp120 and cell surface receptor CD4, resulting in the inhibition of infection [40]; however, a member of a-defensins, human neutrophil peptide 1 (HNP1), is proved to up-regulate type I interferon response gene of trout head kidney leukocytes [41].…”

“…Studies against NNV were focused on the development of vaccine, immuno-stimulants and other means [22,23]. However, ever since the first report on the antiviral activities of cecropin B against infectious hematopoietic necrosis virus (IHNV), viral hemorrhagic septicemia virus (VHSV), snakehead rhabdovirus (SHRV), and infectious pancreatic necrosis virus (IPNV) [24], more emerging studies are highlighting the benefits of AMP application on disease control, for example, not eliciting resistance in bacteria, compared with conventional antibiotic therapeutics. In this study, we examined the antiviral activities of three AMPs against NNV in fish cells, and elucidated their anti-NNV mechanisms in vitro.…”

Application of antimicrobial peptides in agriculture and food industry

“…Some fungi, such as Candida albicans and Microsporosis sanis, were also sensitive to this synthetic peptide (Yin et al 2006). Antiviral effects of cecropin B and its synthetic analog, C17, against several important pathogens of fish such as infectious hematopoietic virus, viral hemorrhagic septicemia virus, snakehead rhabdovirus and infectious pancreatic necrosis virus were proved in another report (Chiou et al 2002). Probably the peptide acts via inhibition of viral replication by viral envelope disruption and viral capsid disintegration.…”

“…To attain this goal a plant transformation vector was constructed with transcriptional Antibacterial effect in transgenic rice, antiviral effect against important viral pathogens of fish Sharma et al (2000) and Chiou et al (2002) Lactoferricin Cow (Bos taurus) Mastitis control in goat Zhang et al (2007) alfAFP Plant Alfalfa (Medicago sativa) Antifungal effect in transgenic potato Gao et al (2000) Pn-AMP2 Morning glory (Pharbitis nil) Antifungal effect in transgenic tobacco Koo et al (2002) CEMA Synthetic Chimera (cecropin-melittin) Antifungal effect in transgenic tobacco, antibacterial effect against bacterial pathogen in fish Yevtushenko et al (2005) and Jia et al (2000) MSI-99 Magainin analog Antifungal and antibacterial effect in transgenic tobacco, tomato, grapevine, banana Chakrabarti et al (2003), Vidal et al (2003) and Alan et al (2004) Polyoxins Microbial Streptomyces cacaoi Fungicide, insecticide Reuveni et al (2000) and Arakawa (2003) fusion between the pathogen responsive win3.12T promoter from poplar and the gene encoding the novel hybrid peptide, CEMA. Expression level of the peptide as regulated by the win3.12T promoter was sufficient to confer resistance against highly virulent fungus Fusarium solani in transgenic tobacco (Yevtushenko et al 2005).…”

Inactivation of nervous necrosis virus infecting grouper (Epinephelus coioides) by epinecidin-1 and hepcidin 1–5 antimicrobial peptides, and downregulation of Mx2 and Mx3 gene expressions

“…In vitro characterization of native cecropin B and a synthetic analogue, CF17, against several important fish viral pathogens by the methods of co-incubation of these peptides and viruses caused reductions in viral titers yielded in fish cells from several fold to 104-fold. These results suggested inhibition of viral replication by the peptides by direct disruption of the viral envelope and disintegration of the viral capsids [16,17]. Fish nodaviruses are icosahedral, naked, nonenveloped, single-stranded RNA viruses of 25-30 nm which cause up to 100% mortality in fry and fingerling stages of grouper.…”