Download The Atlantic salmon immune response to viruses, bacteria and

Marine Scotland, Aberdeen, UK
University of Tromsø, Tromsø, Norway
School of Veterinary Science, Oslo, Norway
The Atlantic salmon immune response to viruses,
bacteria and parasites
Atlantic salmon (Salmo salar) farming represents one of the most important
examples of commercially successful intensive aquaculture in the world. In
Europe the main producers are Norway and UK with a respective estimate of
845,000 and 143,000 tons produced in 2009. In spite of this success, viral,
bacterial and parasitic pathogens pose a serious threat to the European salmon
farming industry and cost millions of euros every year.
The aim
The outcome
What is next?
Animals have developed specialized immune responses to
viruses, bacteria or parasites.
Aeromonas salmonicida, Infectious Pancreatic Necrosis Virus
(IPNV) and Gyrodactylus salaris
belong to these three categories
of pathogens and seriously affect
the European Atlantic salmon
farming industry.
The IMAQUANIM Salmon group
has developed valuable tools to
monitor and characterize the
immune response to the three
types of pathogens. Experimental
infections were carried out using
salmon families showing contrasting levels of resistance to A.
salmonicida, animals vaccinated
against IPNV and salmon from
populations
known
to
be
sensitive or resistance to G. salaris.
Using molecular technologies such
as microarray analysis, Suppression
Subtractive
Hybridisation (SSH) and real time PCR a
collection of novel genes that
proved to be involved in the
response to parasites, viruses or
bacteria were established for
Atlantic salmon.
Molecules part of the interferon
pathway,
the
main
antiviral
immune mechanism, such as
STAT1 and STAT2 were isolated
and used to detect potential viral
suppression. Transcription factors
such as GATA3 were discovered
and can be used as a marker of the
Th2 adaptive response.
Finally, the precise analysis of
genes induced by IPNV in vaccinated fish shed some light on
some aspect of viral infection and
the importance of proteolysis as a
defense mechanism.
We still do not know how the
host survives or succumbs to
a
pathogen
infection.
Tradition-ally, an experimental
infection is monitored by
sacrification at regular intervals after infection of a
number of fish.
There is no way at present to
predict if a fish will die or
survive the infection without
developing methods for nonlethal sampling and immune
response monitoring.
The use of the tools developed during IMAQUANIM
should now be applied to
novel experimental infection
designs to answer to the very
basic question:
What kills the fish? Why do
some survive? How can we
predict this?
Infected CHSE cells: IPNV virus (red)
Mx virus (green)
Infectious Pancreatic Necrosis (IPN)
IPN-Expression profile: STAT2 in kidney
CM: Negative mock infected control.
Phylogenetic tree: Atlantic salmon
GATA-3 and other vertebrate GATA
amino acid sequences
Collet B, Ganne G, Bird S, Collins C. (2009). Isolation and expression profile of a gene encoding for the Signal Transducer
and Activator of Transcription STAT-2 in Atlantic salmon (Salmo salar). Dev Comp Immunol 33(7):821-829.
Kumari J, Bogwald J, Dalmo RA. (2009). Transcription factor GATA-3 in Atlantic salmon (Salmo salar): molecular
characterization, promoter activity and expression analysis. Molec Immunol 46(15): 3099-107.
Marjara IS, Thu BJ, Evensen Ø. (in press). Differentially expressed genes following persistent infection with infectious
pancreatic necrosis virus in vitro and in vivo. Fish & Shellfish Immunol.
IMPROVED IMMUNITY OF AQUACULTURED ANIMALS