Nanogram quantities of a DNA vaccine protect rainbow trout fry against heterologous strains of infectious hematopoietic necrosis virus

The efficacy of a DNA Vaccine containing the glycoprotein gene of infectiou s hematopoietic necrosis virus (IHNV), a rhabdovirus affecting trout and sa lmon, was investigated. The minimal dose of vaccine required, the protectio n against heterologous strains, and the titers of neutralizing antibodies p roduced were used to evaluate the potential of the vaccine as a control pha rmaceutical, Results indicated that a single dose of as little as 1-10 ng o f Vaccine protected rainbow trout fry against waterborne challenge by IHNV. An optimal dose of 100 ng per fish was selected to assure strong protectio n under various conditions. Neutralizing antibody titers were detected in f ish vaccinated with concentrations of DNA ranging from 5 to 0.01 mu g. Furt hermore, the DNA vaccine protected fish against a broad range of viral stra ins from different geographic locations, including isolates from France and Japan, suggesting that the Vaccine could be used worldwide. A single dose of this DNA vaccine induced protection in fish at a lower dose than is usua lly reported in mammalian DNA vaccine studies. Published by Elsevier Scienc e Ltd.