scholarly journals The Nucleoprotein and Phosphoprotein Are Major Determinants of the Virulence of Viral Hemorrhagic Septicemia Virus in Rainbow Trout

2019 ◽  
Vol 93 (18) ◽  
Author(s):  
Vikram N. Vakharia ◽  
Jie Li ◽  
Douglas G. McKenney ◽  
Gael Kurath
Keyword(s):  
Rainbow Trout ◽  
Matrix Protein ◽  
Virulent Strain ◽  
N Gene ◽  
Viral Hemorrhagic Septicemia Virus ◽  
Avirulent Strain ◽  
Viral Hemorrhagic Septicemia ◽  
High Virulence ◽  
Specific Virulence ◽  
Host Component

ABSTRACTViral hemorrhagic septicemia virus (VHSV), a fish rhabdovirus, infects several marine and freshwater fish species. There are many strains of VHSV that affect different fish, but some strains of one genetic subgroup have gained high virulence in rainbow trout (Oncorhynchus mykiss). To define the genetic basis of high virulence in trout, we used reverse genetics to create chimeric VHSVs in which viral nucleoprotein (N), P (phosphoprotein), or M (matrix protein) genes, or the N and P genes, were exchanged between a trout-virulent European VHSV strain (DK-3592B) and a trout-avirulent North American VHSV strain (MI03). Testing of the chimeric recombinant VHSV (rVHSV) by intraperitoneal injection in juvenile rainbow trout showed that exchanges of the viral P or M genes had no effect on the trout virulence phenotype of either parental strain. However, reciprocal exchanges of the viral N gene resulted in a partial gain of function in the chimeric trout-avirulent strain (22% mortality) and complete loss of virulence for the chimeric trout-virulent strain (2% mortality). Reciprocal exchanges of both the N and P genes together resulted in complete gain of function in the chimeric avirulent strain (82% mortality), again with complete loss of virulence in the chimeric trout-virulent strain (0% mortality). Thus, the VHSV N gene contains an essential determinant of trout virulence that is strongly enhanced by the viral P gene. We hypothesize that the host-specific virulence mechanism may involve increased efficiency of the viral polymerase complex when the N and P proteins have adapted to more efficient interaction with a host component from rainbow trout.IMPORTANCERainbow trout farming is a major food source industry worldwide that has suffered great economic losses due to host jumps of fish rhabdovirus pathogens, followed by evolution of dramatic increases in trout-specific virulence. However, the genetic determinants of host jumps and increased virulence in rainbow trout are unknown for any fish rhabdovirus. Previous attempts to identify the viral genes containing trout virulence determinants of viral hemorrhagic septicemia virus (VHSV) have not been successful. We show here that, somewhat surprisingly, the viral nucleocapsid (N) and phosphoprotein (P) genes together contain the determinants responsible for trout virulence in VHSV. This suggests a novel host-specific virulence mechanism involving the viral polymerase and a host component. This differs from the known virulence mechanisms of mammalian rhabdoviruses based on the viral P or M (matrix) protein.

scholarly journals The Viral Hemorrhagic Septicemia Virus (VHSV) Markers of Virulence in Rainbow Trout (Oncorhynchus mykiss)

2020 ◽  
Vol 11 ◽  
Author(s):  
Laury Baillon ◽  
Emilie Mérour ◽  
Joëlle Cabon ◽  
Lénaïg Louboutin ◽  
Estelle Vigouroux ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Viral Hemorrhagic Septicemia Virus ◽  
Viral Hemorrhagic Septicemia ◽  
Rainbow Trout Oncorhynchus Mykiss

scholarly journals Survey of Transcript Expression in Rainbow Trout Leukocytes Reveals a Major Contribution of Interferon-Responsive Genes in the Early Response to a Rhabdovirus Infection

2002 ◽  
Vol 76 (16) ◽  
pp. 8040-8049 ◽  
Author(s):  
Caroline O'Farrell ◽  
Nikta Vaghefi ◽  
Monique Cantonnet ◽  
Bénédicte Buteau ◽  
Pierre Boudinot ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Host Cell ◽  
Natural Infection ◽  
Viral Hemorrhagic Septicemia Virus ◽  
Nucleic Acid Binding ◽  
Global Knowledge ◽  
Viral Hemorrhagic Septicemia ◽  
Predominant Component ◽  
Induced Genes

ABSTRACT Virus infections induce changes in the expression of host cell genes. A global knowledge of these modifications should help to better understand the virus/host cell interactions. To obtain a more comprehensive view of the rainbow trout response to a viral infection, we used the subtractive suppressive hybridization methodology in the viral hemorrhagic septicemia model of infection. We infected rainbow trout leukocytes with viral hemorrhagic septicemia virus (VHSV), and total RNA from infected and mock-infected cells was compared at 40 h postinfection. Twenty-four virus-induced genes were ultimately retrieved from the subtracted cDNA library, and their differential expression was further confirmed by semiquantitative reverse transcription-PCR and Northern blot analysis. Among these sequences, three were already described as VHSV-induced genes. Eight sequences with known homologs were extended to full-length cDNA using 5′ and 3′ rapid amplification of cDNA ends, and they were subsequently divided into three functional subsets. Four genes were homologous to mammalian interferon responsive genes, three were similar to chemo-attractant molecules (CXC chemokine, galectin), and two had nucleic acid binding domains. All of the virus-induced genes were also induced by rainbow trout interferon, indicating that the interferon pathway is the predominant component of the anti-VHSV response. They were also expressed in vivo in experimentally infected fish, indicating their biological relevance in natural infection.

A Leukocytolytic Factor Isolated from Cultures of Aeromonas salmonicida

1977 ◽  
Vol 34 (8) ◽  
pp. 1118-1125 ◽  
Author(s):  
D. W. Fuller ◽  
K. S. Pilcher ◽  
J. L. Fryer
Keyword(s):  
Rainbow Trout ◽  
Virulence Factors ◽  
Coho Salmon ◽  
Virulent Strain ◽  
Deae Cellulose ◽  
Aeromonas Salmonicida ◽  
Salmo Gairdneri ◽  
Amino Sugars ◽  
Avirulent Strain

A substance characterized as a glycoprotein, isolated from the supernatant fluids of broth cultures of Aeromonas salmonicida by a combination of ammonium sulfate and ethanol precipitations followed by chromatography on DEAE-cellulose, was cytolytic for rainbow trout (Salmo gairdneri) leukocytes, and antigenic when injected into rabbits. The ratio of protein to hexose determined by analysis of the purified fraction was between 0.35 and 0.45, and small amounts of amino sugars were detected. A virulent strain of A. salmonicida produced much more of this factor than an avirulent strain. This factor was cytolytic for leukocytes in vitro and also produced a pronounced leukopenia when injected intravenously in adult rainbow trout. When injected in small coho salmon (Oncorhyncus kisutch) 8–13 cm long together with about one LD50 of live A. salmonicida 36 of 40 fish succumbed to the combination, whereas only 14 of 40 died from an injection of the bacterium alone. Thus, the pathogenicity of the organism was enhanced, presumably by increasing the susceptibility of the host. Hence, this glycoprotein apparently is one of the virulence factors of this bacterium. Key words: leukocytolytic factor, Aeromonas salmonicida, glycoprotein, virulence factor

scholarly journals Fish Rhabdovirus Cell Entry Is Mediated by Fibronectin

1999 ◽  
Vol 73 (9) ◽  
pp. 7703-7709 ◽  
Author(s):  
Monique Bearzotti ◽  
Bernard Delmas ◽  
Annie Lamoureux ◽  
Anne-Marie Loustau ◽  
Stefan Chilmonczyk ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Cell Entry ◽  
Viral Hemorrhagic Septicemia Virus ◽  
Cell Plasma Membrane ◽  
Viral Hemorrhagic Septicemia ◽  
Cell Plasma ◽  
Lower Vertebrates ◽  
Blocking Activity ◽  
Molecular Masses ◽  
Heterodimeric Complex

ABSTRACT Three monoclonal antibodies (MAbs) generated against rainbow trout gonad cells (RTG-2) have been selected for their ability to protect cells from the viral hemorrhagic septicemia virus (VHSV) infection, a salmonid rhabdovirus. Protection from infection was restricted to the salmonid-derived cell lines indicating species specificity of the blocking MAbs. Surprisingly, the blocking activity of these MAbs was also effective against other nonantigenically related fish rhabdoviruses. Indirect immunofluorescence and immunoelectron microscopy observations demonstrated that the three MAbs were all directed against an abundant cell plasma membrane component, and immunoprecipitation studies indicated that the target consisted of a heterodimeric complex with molecular masses of 200 and 44 kDa. Biochemical data provided the following evidence that fibronectin is part of this complex and that it could represent the main receptor for fish rhabdoviruses. (i) An antiserum generated against the 200-kDa protein reacted against the recombinant rainbow trout fibronectin expressed in Escherichia coli. (ii) The purified rainbow trout fibronectin was able to bind specifically to VHSV. To our knowledge, this is the first identification of a cellular component acting as a primary receptor for a virus replicating in lower vertebrates and, more interestingly, for viruses belonging to theRhabdoviridae family.

Sign in / Sign up

Export Citation Format

Share Document