Protective immunity and lack of histopathological damage two years after DNA vaccination against infectious hematopoietic necrosis virus in trout.
The DNA vaccine pIHNw-G encodes the glycoprotein of the fish rhabdovirus infectious hematopoietic necrosis virus (IHNV). Vaccine performance in rainbow trout was measured 3, 6, 13, 24, and 25 months after vaccination. At three months all fish vaccinated with 0.1 microg pIHNw-G had detectable neutralizing antibody (NAb) and they were completely protected from lethal IHNV challenge with a relative percent survival (RPS) of 100% compared to control fish. Viral challenges at 6, 13, 24, and 25 months post-vaccination showed protection with RPS values of 47-69%, while NAb seroprevalence declined to undetectable levels. Passive transfer experiments with sera from fish after two years post-vaccination were inconsistent but significant protection was observed in some cases. The long-term duration of protection observed here defined a third temporal phase in the immune response to IHNV DNA vaccination, characterized by reduced but significant levels of protection, and decline or absence of detectable NAb titers. Examination of multiple tissues showed an absence of detectable long-term histopathological damage due to DNA vaccination.
Kurath
Gael
G
U.S.G.S. Western Fisheries Research Center, 6505 NE 65th St., Seattle, WA 98115, USA. gael.kurath@usgs.gov
Garver
Kyle A
KA
Corbeil
Serge
S
Elliott
Diane G
DG
Anderson
Eric D
ED
LaPatra
Scott E
SE
D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis / Q000096:biosynthesis; D005393:Fish Diseases / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control*; D007116:Immunization, Passive; D029142:Infectious hematopoietic necrosis virus / Q000276:immunology*; D009500:Neutralization Tests; D017686:Oncorhynchus mykiss / Q000276:immunology* / Q000821:virology*; D018353:Rhabdoviridae Infections / Q000276:immunology* / Q000473:pathology / Q000662:veterinary*; D014611:Vaccination; D019444:Vaccines, DNA / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology*
D000914:Antibodies, Viral; D019444:Vaccines, DNA; D014765:Viral Vaccines