Hatchery-reared salmonid fish routinely encounter stress due to
handling, barging, tagging, and overcrowding. It has been demonstrated that
there exists a direct correlation between stress and transient immune
suppression which can last for many days in fish. Epizootic viral infections
routinely appear in hatcheries and can have a devastating effect on the fish
population. The major viral pathogens in salmon and trout are the fish
rhabdovirus, infectious hematopoietic necrosis virus (IHNV), and the fish
birnavirus, infectious pancreatic necrosis virus (IPNV). Vaccines for these
viral pathogens are under investigation; however, the fish immune system
becomes virtually nonresponsive during episodes of immune suppression. It
was necessary to develop a nonantibody mediated, nonimmune method for
preventing viral infections.
An interferon-like substance has been described for fish which
possesses antiviral activity against both IHNV and IPNV. Since interferon
administered to cattle has been very effective against vesicular stomatitis
virus, a cattle rhabdovirus, an examination of interferon-like activity in fish was
initiated. We report here the establishment of in vitro interferon assays. In
addition, the salmonid genome contains a multigene family of p-interferon-like
genes, much like those in the bovine, equine and porcine genome. The
rainbow trout interferon-like genes were found to be inducible in a manner
which parallels those seen with bovine and human interferons.
In addition to the multigene interferon-like family, it was found that
rainbow trout also contain a retroposon multigene family. Retroposons are
repetitive elements which appear to have arisen by a reverse transcription
event. Two Ll like repetitive elements have been cloned, one of which
contains a Drosophila retroposon polymerase sequences never before
described for salmonid fish. A number of retroviruses have been described in
fish including the walleye dermal sarcoma virus and the Atlantic salmon
swimbladder sarcoma virus. Interferon shows prophylactic promise both in
vivo and in vitro, against the human retrovirus, HIV. Therefore, research into
fish interferon may be even more important if it demonstrates not only anti-
IHNV and anti-IPNV, but also anti-fish retrovirus properties. / Graduation date: 1993
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/36125 |
| Date | 11 August 1992 |
| Creators | Tengelsen, Leslie A. |
| Contributors | Leong, Jo-Ann C. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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