WO2012066481A1

WO2012066481A1 - New ethiological agent

Info

Publication number: WO2012066481A1
Application number: PCT/IB2011/055103
Authority: WO
Inventors: Pål NILSEN; Marianne FRØYSTAD-SAUGEN; Karine Lindmo; Aase Beathe Mikalsen; Øystein EVENSEN; Marit Rode
Original assignee: Pharmaq As
Priority date: 2010-11-15
Filing date: 2011-11-15
Publication date: 2012-05-24
Also published as: EP2640832A1; CA2817933A1; CL2013001330A1; NO2640832T3; EP2640832A4; EP2640832B1

Abstract

The present invention relates to an isolated non-enveloped, positive stranded RNA virus. The invention further relates to an isolated nucleic acid sequence transcribed from the viral genome and to isolated or recombinant amino acid sequences corresponding to proteins encoded by a nucleic acid sequence within an open reading frame in the viral genome. The invention further provides antibodies, nucleic acid sequences, immunogenic compositions and methods of manufacturing such, methods of detecting the virus, and diagnostic kits. Finally, the invention also provides a virus of the invention for use in medicine and use of a virus of the invention in the manufacture of an immunological composition.

Description

New ethiological agent

Field of invention

The present invention pertains to a novel ethological agent, a virus identified in Atlantic salmon. The invention further relates to subject-matter which is useful for controlling viral infections, including the isolated virus, immunological

compositions and diagnostic tools.

Background of the invention

Caliciviridae are small, non-enveloped, positive-stranded RNA viruses. The

Caliciviridae are at present divided into five groups, tentatively designated distinct genera, on the basis of sequence relatedness and genomic organization (2). Four groups are known human pathogens, while the fifth group Lagovirus, where Rabbit Haemmoraghic Virus is a member, is not known to be a human pathogen. The only group of caliciviruses which can be grown in vitro, is the group of marine caliciviruses belonging to the genus Vesivirus, where the virus causing vesicular exanthema of swine (VES) is a member. The virus causing vesicular exanthema of swine (VES) has been known to have a reservoir in marine mammals, and can also infect swine (1). Many species of marine mammals are known to be susceptible to calicivirus infection. A calicivirus has also been found in a marine fish species, the opaleye perch (3), and this virus belonged to the same group, Vesivirus, as the VES-virus found in marine mammals.

Caliciviruses are believed to be involved in disease development in salmonids. The disease is systemic and can result in inflammation of the heart. The liver and kidney tissue can also be affected, as well as other tissues. While infection with calicivirus in salmonids may in many cases be asymptomatic, the presence of calicivirus in fish for human consumption is nevertheless highly undesirable.

Consequently, there is an urgent need to isolate and characterize the calicivirus which infect salmonids and to devise prophylactic and therapeutic approaches to the control of such infections in farmed fish.

Summary of the invention

An object of the present invention relates to an isolated non-enveloped, positive stranded RNA virus, wherein said virus is selected from the group consisting of: I) the viral isolate A2-G01 deposited under the Budapest Treaty with the European Collection of Cell culture (ECACC), Health Protection Agency, Porton Down, Salisbury, Wiltshire (UK), SP4 OJG UK on January 7 2010 under deposit number 10010701; and II) a virus which is related to the viral isolate in I) and which comprises in its genome a ribonucleic acid sequence which by reverse transcription and 2^nd strand synthesis provides a sequence which is at least 65 % identical to the sequence set forth in SEQ ID NO: 1, and/or is at least least 65 % identical to the sequence set forth in SEQ ID NO: 2.

Further objects of the invention relate to isolated nucleic acid sequences, isolated or recombinant proteins or amino acid sequences, antibodies, immunogenic compositions, diagnostic methods and kits and the virus, isolated nucleic acid sequences and isolated or recombinant amino acid sequences for use in medicine.

Description of the drawings

Figure 1 : Schematic representation of polyprotein RHDVgpl and parts of processed products: RHase-dependent RNA polymerase (RdRp) and coatl (major coat protein).

Figure 2: GF-1 cells infected with 33% cell culture medium from cells displaying cpe. 17 days after infection (A) and GF-1 control cells, not infected, 17 days after infection (B).

Figure 3. Amino acid sequence from open reading frame (ORF) in the genome of salmonid callicivirus isolate A2-G01 : Sequence marked in bold : RdRp (specific domain hit); underlined sequence: Coat (specific domain hit) comprising putative S-domain; underlined sequence marked in bold : Coat protein, putative P-domain.

Figure 4. Alignment of coat protein from different caliciviruses.

Figure 5. Phylogram obtained by Maximum likelihood (ML) analysis in the software package MEGA 5 of the conserved region in the putative capsid protein of selected Caiiciviruses. A model for amino acid substitution (rtREV+G+F) was selected using Model Selection. The tree was bootstrapped with 100 replicates under a ML criterion and midpoint rooted for presentation. The bootstrap consensus tree is shown.

Figure 6. Phylogram obtained by Maximum likelihood (ML) analysis in the software package MEGA 5 of the conserved region in the putative RNA dependent RNA polymerase of selected Caiiciviruses. A model for amino acid substitution (WAG+G+I) was selected using Model Selection. The tree was bootstrapped with 100 replicates under a ML criterion and midpoint rooted for presentation. The bootstrap consensus tree is shown.

Figure 7. Phylogram obtained by Maximum likelihood (ML) analysis in the software package MEGA 5 of the putative protease domain of selected Caiiciviruses. A model for amino acid substitution (WAG+G) was selected using Model Selection. The tree was bootstrapped with 100 replicates under a ML criterion and midpoint rooted for presentation. The bootstrap consensus tree is shown.

Figure 8. Phylogram obtained by Maximum likelihood (ML) analysis in the software package MEGA 5 of the putative RNA Helicase domain of selected Caiiciviruses. A model for amino acid substitution (WAG+G+I) was selected using Model Selection. The tree was bootstrapped with 100 replicates under a ML criterion and midpoint rooted for presentation. The bootstrap consensus tree is shown. Figure 9. Receipt for deposition, viral isolate A2-G01.

Detailed description of the invention

The present invention provides a new caiicivirus isolated from Atlantic salmon in Norway. The new caiicivirus shares only limited sequence homology with the other known caiiciviruses, and will probably constitute a new genus under the species caiicivirus. The present inventors propose the name salmonid caiicivirus. The virus was isolated by seeding of homogenate from diseased fish onto cell culture. The material was passaged several times through cell culture before a cytopathogenic effect was observed. The genome was cloned and sequenced using a subtraction cloning method. The isolated virus and the nucleic acid sequences and amino acid sequences according to the present invention allows preparation of vaccines and diagnostic tools for calicivirus infections in fish.

Definitions

The term "isolated" when applied in relation to a nucleic acid sequence or amino acid sequence, refers to the nucleic acid sequence or amino acid sequence in a preparation containing reduced amounts of the material with which the nucleic acid sequence or amino acid sequence is natively associated.

In particular, the term "isolated" may refer to a "substantially pure nucleic acid sequence" or a "substantially pure amino acid sequence" meaning a preparation of the nucleic acid sequence or the amino acid sequence which contains at most 5% by weight of other nucleic acid sequences and/or amino acid sequences with which it is natively associated (lower percentages of other nucleic acid sequences and/or amino acid sequences are preferred, e.g. at most 4%, at most 3%, at most 2%, at most 1%, and at most ¹/_%). It is preferred that the substantially pure nucleic acid sequence is at least 96% pure, i.e. that the nucleic acid sequence or a plasmid or vector comprising the nucleic acid sequence constitutes at least 96% by weight of the total nucleic acid sequences present in the preparation, and higher percentages are preferred, such as at least 97%, at least 98%, at least 99%, at least 99,25%, at least 99,5%, and at least 99,75%.

Likewise it is preferred that the amino acid sequence constitutes at least 96% by weight of the total amino acid sequences present in the preparation, and higher percentages are preferred, such as at least 97%, at least 98%, at least 99%, at least 99,25%, at least 99,5%, and at least 99,75%. This definition does not exclude the situation where a substantially pure amino acid sequence is combined with other substantially pure amino acid sequences, e.g. in a composition for therapeutic use.

It is especially preferred that the nucleic acid sequence or amino acid sequence is in "essentially pure form", i.e. that the nucleic acid sequence or amino acid sequence is free of any other nucleic acid sequences and/or amino acid sequences with which it is natively associated, e.g. free of any other other nucleic acid sequences and/or amino acid sequences natively found in cells from piscine species, in particular salmonid species. This can be accomplished by preparing the nucleic acid sequence or amino acid sequence by means of recombinant methods in a non-piscine host cell, such as a non-salmonid host cell, as will be described in detail below, or by synthesizing the amino acid sequence by the well-known methods of solid or liquid phase peptide synthesis.

When used in relation to the virus of the present invention, the term "isolated" refers to the virus when separated from its natural environment, such as the cells and tissues from its piscine host. In particular, the term "isolated" refers to a culture, such as a pure culture of the virus derived from a tissue sample from an infected host. As viruses cannot reproduce on their own and use host cell machinery to make both the viral genome and capsids, the term "isolated" may in particular refer to a culture of cells infected with the virus.

The term "isolated" may further refer to a virus which is substantially free of other viral or microbial material. The term "substantially free of other viral or microbial material" as used herein refers to a preparation of a virus in which other viral or microbial material cannot be detected using conventional techniques like seeding on TSA or cystein heart agar spread plates, seeding in cell cultures known to support the growth of fish viruses like Pancreas Disease Virus, Infectious Salmon Anemia virus and Infectious pancreatic Necrosis virus and PCR with primers designed against known sequences from fish pathogens. Further, it is to be understood that when "substantially free of other viral or microbial material" the virus of the invention is in a form wherein it may be used for therapeutic purposes. This definition does not exclude applications in which a pure culture of the virus according to the invention is combined with other vaccine antigens, e.g. other bacterial or viral antigens in compositions, e.g. compositions intended for vaccination purposes. The term "sequence identity" indicates a quantitative measure of the degree of homology between two amino acid sequences or between two nucleic acid sequences. If the two sequences to be compared are not of equal length, they must be aligned to give the best possible fit, allowing the insertion of gaps or, alternatively, truncation at the ends of the polypeptide sequences or nucleotide

{N„f-N_dif)l00

sequences. The sequence identity can be calculated as ^N"^f , wherein Ndif is the total number of non-identical residues in the two sequences when aligned and wherein Nref is the number of residues in one of the sequences. Hence, the DNA sequence AGTCAGTC will have a sequence identity of 75% with the sequence AATCAATC (Ndif=2 and Nref=8). A gap is counted as non-identity of the specific residue(s), i.e. the DNA sequence AGTGTC will have a sequence identity of 75% with the DNA sequence AGTCAGTC (Ndif=2 and Nref=8).

With respect all embodiments of the invention relating to nucleotide sequences, the percentage of sequence identity between one or more sequences may also be based on alignments using the clustalW software

(http:/www.ebi.ac.uk/clustalW/index.html) with default settings. For nucleotide sequence alignments these settings are: Alignment=3Dfull, Gap Open 10.00, Gap Ext. 0.20, Gap separation Dist. 4, DNA weight matrix: identity (IUB). For amino acid sequence alignments the settings are as follows: Alignment=3Dfull, Gap Open 10.00, Gap Ext. 0.20, Gap separation Dist. 4, Protein weight matrix:

Gonnet.

Alternatively, nucleotide sequences may be analysed using programme DNASIS Max and the comparison of the sequences may be done at

http://www.paraliqn.org/. This service is based on the two comparison algorithms called Smith-Waterman (SW) and ParAlign. The first algorithm was published by Smith and Waterman (1981) and is a well established method that finds the optimal local alignment of two sequences. The other algorithm, ParAlign, is a heuristic method for sequence alignment; details on the method are published in Rognes (2001). Default settings for score matrix and Gap penalties as well as E- values were used.

The term "immunogenic" when used in relation to a polypeptide or protein or in relation to a subsequence of a polypeptide or protein implicates the ability of said polypeptide, protein or subsequence to elicit an immune response in a biological sample or in an individual currently or previously infected with a salmonid calicivirus, such as a salmonid calicivirus as defined hereinbelow.

The immune response to a polypeptide, a protein or a subsequence of a polypeptide or protein may in particular be a humoral response as determined by a specific antibody response in an immune or infected individual. The presence of antibodies in serum may be determined in vitro by the ELISA technique or in a Western blot where the polypeptide or protein or the subsequence of a

polypeptide or protein is absorbed to either a nitrocellulose membrane or a polystyrene surface. By the use of labeled secondary antibodies the presence of specific antibodies can be determined by measuring the optical density (O.D.) e.g. by Enzyme-linked immunosorbent assay (ELISA) where a positive response is a response of more than background plus two standard deviations or, alternatively, a visual response in a Western blot.

The serum may preferably be diluted in PBS from 1 : 10 to 1 : 100 and added to the absorbed polypeptide, protein or subsequence of polypeptide or protein. The serum is preferably incubated with the absorbed polypeptide, protein or subsequence of polypeptide or protein from 1 to 12 hours. Another relevant approach to determining an immune response to a polypeptide, a protein or a subsequence of a polypeptide or protein is measuring the protection in animal models induced after vaccination with the polypeptide, the protein or the subsequence of a polypeptide or protein in an adjuvant. A suitable animal model in this context is a salmonid. Read-out for induced protection could be decrease of the bacterial load in target organs compared to non-vaccinated animals, prolonged survival times compared to non-vaccinated animals and diminished weight loss compared to non-vaccinated animals.

The term "immunogenic" when used in relation to a polypeptide or protein or in relation to a subsequence of a polypeptide or protein may further imply the presence within said polypeptide, protein or said subsequence of a polypeptide or protein of one or more immunogenic potions, such one or more epitopes for B- cells and/or one or more epitopes for T-cells. B-cell epitopes, in particular, can be determined by analysing the B cell recognition to overlapping peptides covering the polypeptide of interest. As the skilled person will understand, "cytopathogenic effect" refers to visible morphologic changes in cells infected with viruses. It may in particular include shutdown of cellular RNA and protein synthesis, cell fusion, release of lysosomal enzymes, changes in cell membrane permeability, diffuse changes in intracellular structures, presence of viral inclusion bodies, and chromosomal aberrations.

"Cell culture" refers to cultures of cells, such as transformed cells, established in vitro. Specifically, as used herein, "cell line" refers to a population of cells capable of continuous or prolonged growth and division in vitro. Often, cell lines are clonal populations derived from a single progenitor cell. It is further known in the art that spontaneous or induced changes can occur in karyotype during storage or transfer of such clonal populations. Therefore, cells derived from the cell line referred to may not be precisely identical to the ancestral cells or cultures, and the cell line referred to includes such variants. The term "cell lines" also includes immortalized cells.

Finally, in the context of the present invention, a "polyvalent vaccine" (also referred to as a "multivalent vaccine") is used to define a combination of several antigens in one vaccine. Thus, a polyvalent vaccine may protect against more than one disease. As opposed to a polyvalent vaccine, a "monovalent vaccine" is a vaccine containing vaccine components directed at only one pathogen. In particular, a monovalent vaccine may contain only one antigen, protecting against one particular disease.

In a first aspect the invention provides an isolated non-enveloped, positive stranded RNA virus, wherein said virus is selected from the group consisting of:

I) the viral isolate A2-G01 deposited under the Budapest Treaty with the

European Collection of Cell culture (ECACC), Health Protection Agency, Porton Down, Salisbury, Wiltshire (UK), SP4 OJG UK on January 7 2010 under deposit number 10010701; and

II)a virus which is related to the viral isolate in I), such as a variant of said viral isolate in I), and which comprises in its genome a ribonucleic acid sequence which by reverse transcription and 2. strand synthesis provides a sequence which is at least 65% identical to the sequence set forth in SEQ ID NO : 1 and/or is at least 65% identical to the sequence set forth in SEQ ID NO : 2.

Alternatively phrased, the said virus, which is related to the viral isolate in I), comprises in its genome a ribonucleic acid sequence, which is at least 65% identical to the sequence set forth in SEQ ID NO: 3 and/or is at least 65% identical to the sequence set forth in SEQ ID NO: 4.

In further embodiments the virus comprises, in its genome, a nucleic acid sequence which by reverse transcription and 2. strand synthesis provides a 5 sequence which is at least 70% identical, such as at least, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.8% or 99.9% identical, to the sequence set forth in SEQ ID NO: 1 and/or to the sequence set forth in SEQ ID NO: 2.

According to these embodiments the virus comprises, in its genome, a nucleic acid sequence which is at least 70% identical, such as at least, 75%, 80%, 85%, 90%, 10 95%, 96%, 97%, 98%, 99%, 99.5%, 99.8% or 99.9% identical, to the sequence set forth in SEQ ID NO: 3 and/or to the sequence set forth in SEQ ID NO: 4.

According to specific embodiments of the invention, the virus comprises in its genome a ribonucleic acid sequence which is 100% identical to the sequence set forth in SEQ ID NO: 3 and/or is 100% identical to the sequences set forth in SEQ 15 ID NO: 4 so that said sequence by reverse transcription and 2. strand synthesis provides the DNA sequence set forth in SEQ ID NO: 1 and/or SEQ ID NO: 2.

In particular embodiments the virus may comprise a sequence which has been derived from the sequence set forth in SEQ ID NO: 3 and/or from the sequence set forth in SEQ ID NO: 4 by deletion, addition and/or modification of one or more

20 ribonucleic acid residues, such as from 1-10 ribonucleic acid residues, such as from 11-20 ribonucleic acid residues, from 21-30 ribonucleic acid residues or from 31-50 ribonucleic acid residues. In particular 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 ribonucleic acid residues may have been deleted, modified or added. According to these embodiments, reverse transcription and 2^nd

25 strand synthesis results in a sequence that differs from the sequence set forth in SEQ ID NO: 1 and/or from the sequence set forth in SEQ ID NO: 2 by deletion, addition and/or modification of one or more nucleic acid residues, such as from 1- 10 nucleic acid residues, such as from 11-20 nucleic acid residues, from 21-30 nucleic acid residues or from 31-50 nucleic acid residues. In particular the

30 sequence differs from the sequence set forth in SEQ ID NO: 1 and/or from the sequence set forth in SEQ ID NO: 2 by deletion, addition and/or modification of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 nucleic acid residues. Studies of the genomic sequence of a salmonid callicivirus according to the present invention has identified one open reading frame. The open read ing frame comprises nucleic acid residues 113-4438 in the sequence set forth in SEQ ID NO : 1. This ORF encodes a polyprotein, RHDVgp l, which is processed into at least an RNA-dependent RNA polymerase (Rd Rp) and coatl (major coat protein) . The polyprotein and the processed products are shown in Figure 1.

The virus according to the invention may further be a virus wherein the genome of said virus comprises an open read ing frame encoding a sequence selected from the g roup consisting of:

I) An amino acid sequence as set forth in any one of SEQ ID NO : 5,

SEQ ID NO : 6, SEQ ID NO : 7, SEQ ID NO : 8 and/or SEQ ID NO : 9. II) An amino acid sequence which is at least 75% identical to any one of the seq uences in I), such as an amino acid seq uence which has been derived from any of said sequences in I) and/or II) by deletion, addition and/or mod ification of one or more amino acid residues.

Table 1 : Nucleotide and amino acid sequences according to the invention .

SEQ ID NO : 1 Nucleotide sequence from the genome of salmonid

calicivirus isolate A2-G01 (nucleic acid residues 1- 4759)

SEQ ID NO : 2 Nucleotide sequence of the full length genome of

salmonid calicivirus isolate A2-G01 (nucleic acid resid ues 1-7433)

SEQ ID NO : 3 Ribonucleotide seq uence from the genome of salmonid

calicivirus isolate A2-G01 (nucleic acid residues 1- 4759)

SEQ ID NO : 4 Ribonucleotide seq uence of the full length genome of

salmonid calicivirus isolate A2-G01 (nucleic acid resid ues 1-7433)

SEQ ID NO : 5 Amino acid seq uence from open reading frame (ORF) in

the genome of salmonid callicivirus isolate A2-G01

SEQ ID NO : 6 Partial amino acid sequence of the RNA-dependent RNA

polymerase ded uced from the open reading frame of salmonid callicivirus isolate A2-G01 (resid ues 485-755 of SEQ ID NO : 5) SEQ ID NO: 7 SEQ ID NO: 7. Amino acid sequence of coat protein

deduced from the open reading frame of salmonid

callicivirus isolate A2-G01, including putative S- and P- domains (residues 920-1441 of SEQ ID NO: 5)

SEQ ID NO: 8 Partial amino acid sequence of coat protein deduced from the open reading frame of salmonid calicivirus isolate A2- G01 (residues 911-1081 of SEQ ID NO: 5)

SEQ ID NO: 9 Sequence from the putative P-domain of salmonid

calicivirus isolate A2-G01 (residues 1081-1441 of SEQ ID NO: 5)

In particular, the genome of said virus may comprise an open reading frame encoding a sequence which is at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.8% or 99.9% identical to the amino acid sequence set forth in any of SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8 or SEQ ID NO: 9. In particular, the virus may comprise a sequence which has been derived from any of SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8 or SEQ ID NO: 9 by deletion, addition and/or modification of one or more amino acid residues, such as from 1-10 amino acid residues, such as from 11-20 amino acid residues, from 21-30 amino acid residues or from 31-50 amino acid residues. In particular 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 amino acid residues may have been deleted, modified or added.

In further embodiments the genome of said virus encodes an RNA-dependent RNA polymerase comprising an amino acid sequence selected from the group consisting of

I) The amino acid sequence set forth in SEQ ID NO: 6;

II) An amino acid sequence which is at least 75% identical, such as at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.8% or 99.9% identical, to the sequence in I), such as an amino acid sequence which has been derived from said sequence in I) by deletion, addition and/or modification of one or more amino acid residues, such as from 1-10 amino acid residues, such as from 11- 20 amino acid residues, from 21-30 amino acid residues or from 31- 50 amino acid residues. In particular 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 amino acid residues may have been deleted, modified or added.

In even further embodiments the genome of said virus encodes a coat protein comprising an amino acid sequence selected from the group consisting of

I) The amino acid sequence set forth in SEQ ID NO: 7, SEQ ID NO: 8 and/or SEQ ID NO: 9;

In particular, the virus according the invention is an attenuated or inactivated virus.

As the skilled person will realize, replication of RNA virus genomes is accompanied by very high mutation rates (Watson et al. 1987). This is due to the lack of proofreading activity of RNA virus polymerases, which leads to a constant generation of new genetic variants e.g. during virus propagation (Elena and Sanjuan (2005). The virus according to the invention may therefore, in certain embodiments, be a virus, which is obtainable by growing viral isolate A2-G01 on a cell culture, such as for one or more passages, such as from 2-20 passages, from 5-20 passages, from 10-20 passages, from 2-15 passages, from 2-10 passages, from 2-5 passages, from 5-20 passages, from 5-15 passages, from 5-10 passages or such as for 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 passages, and/or until a cytopathogenic effect is obtained. Preferably, such a cell culture is selected from the group consisting of: GF-1 cells (derived from the fin tissue of a grouper (Epinephelus coioides), CHH-1 cells (available from ATCC under deposit number CRL-1680), CHSE-214 cells (available from ATCC, deposit number CRL 1681 and from ECACC under deposit number 91041114). In each passage, viral infection of said cells may be obtained by infection with 1/3 of the culture medium from the previous passage + 2/3 of fresh medium.

Viral isolates, which are within the scope of the present invention, may be identified as being capable of binding to an antibody, which is raised against viral isolate A2-G01 as deposited under deposit number 10010701 and/or being capable of binding to an antibody, which is raised against an amino acid sequence as set forth in any of SEQ ID NOs: 5-9. The said antibody may be a polyclonal antibody (antiserum), such as an antiserum from a salmonid which has been infected with viral isolate A2-G01, or it may be a monoclonal antibody. It will be within the capacity of a person of skills in the art to produce such antibodies, using conventional technology available in the art.

According to other aspects the invention provides an isolated nucleic acid sequence encoding an amino acid sequence as defined above.

In particular embodiments the invention pertains to a nucleic acid sequence, which comprises or consists of a sequence selected from the group consisting of:

I) The nucleic acid sequence set forth in SEQ ID NO: 1, SEQ ID NO: 2,

SEQ ID NO: 3 or SEQ ID NO: 4;

Π) A subsequence of the nucleic acid sequence set forth in SEQ ID NO:

1, SEQ ID NO: 2, SEQ ID NO: 3 or SEQ ID NO: 4; and

III) A nucleic acid sequence which is at least 75 % identical, such as at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.8% or 99.9% identical, to any one of the sequences in I) or II), such as a sequence which has been derived from the sequence set forth in SEQ ID NO: 1, 2, 3 or 4 by deletion, addition and/or modification of one or more nucleic acid residues, such as from 1-10 nucleic acid residues, such as from 11-20 nucleic acid residues, from 21-30 nucleic acid residues or from 31-50 nucleic acid residues. In particular the sequence may differ from the sequence set forth in SEQ ID NO: 1 or 2 by deletion, addition and/or modification of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 nucleic acid residues, According to particular embodiments the said subsequence of the nucleic acid sequence set forth in SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3 or SEQ ID NO: 4 has a length of from 10-20, 10-50, 10-100, 10-150, 10-200, 20-50, 20-100, 20-150, 20-200, 30-50, 30-100, 30-150, 30-200, 40-100, 40-150, 40-200, 50- 5 100, 50-150, 50-200, 50 -300, 50-400, 50-500, 50-750, 50-1500, 50-2000, 50- 3000, 50-4000, 50-4500, 50-4700, 100-150, 100-200, 100-500, 100-1000, 100- 2000, 100-3000, 100-4000, 100-4500, 100-4700, 200-1000, 200-3000, 200- 4000, 200-4500, 200-4700, 500-1000, 500-2000, 500-3000, 500-4000, 500- 4500, 500-4700, 1000-2000, 1000-3000, 1000-4000, 1000-4500, 1000-4700,

10 2000-3000, 2000-4000, 2000-4500, 2000-4700, 2000-5000, 2000-6000, 2000- 7000, 2000-7400, 3000-3500, 3000-4000, 3000-4500, 3000-4700, 3000-4750, 3000-5000, 3000-6000, 3000-7000, 3000-7400, 3500-4000, 3500-4500, 3500- 4700, 3500-5000, 3500-6000, 3500-7000, 3500-7400, 4000-4500, 4000-4700, 4000-4750, 4000-5000, 4000-6000, 4000-7000, 4000-7400, 4000-4750, 4500-

15 4700, 4500-5000, 4500-6000, 4500-7000, 4500-7400, 5000-6000, 5000-7000, 5000-7400, 5500-6000, 5500-7000, 5500-7400, 6000-6500, 6000-7000, 6000- 7400, 6500-7000, 6500-7400 or from 7000-7400 consecutive nucleic acid residues.

20 In further embodiments the said nucleic acid sequence and/or subsequence is a sequence which encodes an amino acid sequence, which is immunogenic.

In further embodiments the said subsequence in II) is selected form the group consisting of:

25 i) a sequence comprising nucleic acid residues 1568-2377 of the

sequence set forth in SEQ ID NO: 1 or SEQ ID NO: 3; corresponding to nucleic acid residues 4241-5051 of the sequence set forth in SEQ ID NO: 2 or SEQ ID NO: 4 (sequence encoding SEQ ID NO: 6); and ii) a sequence comprising nucleic acid residues 2842-3355 of the

30 sequence set forth in SEQ ID NO: 1 or SEQ ID NO: 3; corresponding to nucleic acid residues 5517-6029 of the sequence set forth in SEQ ID NO: 2 or SEQ ID NO: 4 (sequence encoding SEQ ID NO: 8).

In particularly preferred embodiments the said subsequence in II) is selected form the group consisting of: i) A sequence comprising nucleic acid residues 2872-4435 of the sequence set forth in SEQ ID NO : 1 or SEQ ID NO: 3; corresponding to nucleic acid residues 4546-7109 of the sequence set forth in SEQ ID NO : 2 or SEQ ID NO: 4 (sequence encoding SEQ ID NO: 7);

ii) A sequence comprising nucleic acid residues 3356-4435 of the

sequence set forth in SEQ ID NO : 1 or SEQ ID NO: 3; corresponding to nucleic acid residues 5547-7109 of the sequence set forth in SEQ ID NO: 2 or SEQ ID NO : 4 (sequence encoding SEQ ID NO: 9);

iii) a sequence comprising nucleic acid residues 3356-3862 of the sequence set forth in SEQ ID NO : 1 or SEQ ID NO: 3; corresponding to nucleic acid residues 5547-6536 of the sequence set forth in SEQ ID NO: 2 or SEQ ID NO : 4 (sequence encoding amino acid residues 1081-1250 of SEQ ID NO: 5); and

iv) a sequence comprising nucleic acid residues 3637-4435 of the sequence set forth in SEQ ID NO : 1 or SEQ ID NO: 3; corresponding to nucleic acid residues 6311-7109 of the sequence set forth in SEQ ID NO: 2 or SEQ ID NO : 4 (sequence encoding amino acid residues 1175-1441 of SEQ ID NO: 5).

A further aspect of the invention provides a plasmid or vector comprising a nucleic acid sequence as defined above.

Yet a further aspect of the invention relates to a host cell comprising the isolated nucleic acid sequence defined above; and/or the plasmid or vector defined above.

Other aspects of the invention provide an isolated or recombinant amino acid sequence or an isolated or recombinant protein comprising or consisting of one or more amino acid sequences selected from the group consisting of

I) The amino acid sequence set forth in SEQ ID NO: 5 and/or an amino acid sequence contained within SEQ ID NO: 5, selected from the group consisting of the amino acid sequences set forth in any of SEQ ID NOs: 6-9;

II) A subsequence of any one of the amino acid sequences in i);

III) An amino acid sequence which is at least 75% identical, such as at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.8% or 99.9% identical, to any of the sequences in I) or II), such as an amino acid sequence which has been derived from any of said sequences in I) or II) by deletion, addition and/or modification of one or more amino acid residues, such as from 1-10 amino acid residues, such as from 11-20 amino acid residues, from 21-30 amino acid residues or from 31-50 amino acid residues. In particular

1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 amino acid residues may have been deleted, modified or added .

The skilled person will expect that considerable alterations may be introduced into the amino acid sequences defined in SEQ ID NOs: 5-9 and subsequences thereof without significantly altering their overall structure, function and immunological properties. In particular the skilled person will expect that an amino acid sequence will have the same immunological properties as a sequence defined in SEQ ID NO : 5, 6, 7, 8 or 9 or a subsequence thereof, as long as it is at least 75% identical to the defined sequence. This is supported for instance by Cothia et a\. EMBO j., vol 5, 4, pp. 823-826, 1986, who investiagated the relationship between the divergence of sequence and structure in proteins. Cothia concluded : "A protein structure will provide a close general model for other proteins with which its sequence homology is >50%. If the homology drops to 20% there will be large structural differences that are at present impossible to predict." The said subsequence of the amino acid sequence set forth in SEQ ID NO: 5 may have a length of from 10-20, 10-50, 10-100, 10-150, 10-200, 20-50, 20-100, 20- 150, 20-200, 30-50, 30-100, 30-150, 30-200, 40-100, 40-150, 40-200, 50-100, 50-150, 50-200, 100-150, 100-200, 100-400, 100-600, 100-800, 100-1000, 100- 1200 or 100-1400 consecutive amino acid residues. The said subsequences of the amino acid sequence set forth in SEQ ID NO : 6 may have a length of from 10-20, 10-50, 10-100, 10-150, 10-200, 20-50, 20-100, 20-150, 20-200, 30-50, 30-100, 30-150, 30-200, 40-100, 40-150, 40-200, 50-100, 50-150, 50-200, 50-250, 100- 150, 100-200, 100-250, 100-260 or 100-265 consecutive amino acid residues. Likewise the said subsequence of the amino acid sequence set forth in SEQ ID NO : 7 may have a length of from 10-20, 10-50, 10-100, 10-150, 10-160, 10-170, 20-50, 20-100, 20-150, 20-160, 20-170, 30-50, 30-100, 30-150, 30-160, 30- 170, 40-100, 40-150, 40-160, 40-170, 50-100, 50-150, 50-160, 50-170, 100- 150, 100-160 100-170, 100-180, 100-200, 150-250, 150-300, 150-350, 150- 400, 150-450, 150-500, 200-250, 200-300, 200-350, 200-400, 200-450, 200- 500, 250-300, 250-350, 250-400, 250-450, 250-500, 300-350, 300-400, 300- 450, 300-500, 350-400, 350-450, 350-500, 400-450, 400-500 or 450-500 consecutive amino acid residues. Further, the said subsequence of the amino acid sequence set forth in SEQ ID NO: 8 may have a length of from 10-20, 10-50, 10- 100, 10-150, 10-160, 10-170, 20-50, 20-100, 20-150, 20-160, 20-170, 30-50, 30-100, 30-150, 30-160, 30-170, 40-100, 40-150, 40-160, 40-170, 50-100, 50- 150, 50-160, 50-170, 100-125, 100-150 or 100-160 consecutive amino acid residues. Finally, the said subsequence of the amino acid sequence set forth in SEQ ID NO: 9 may have a length of from 10-20, 10-50, 10-100, 10-150, 10-160, 10-170, 20-50, 20-100, 20-150, 20-160, 20-170, 30-50, 30-100, 30-150, 30- 160, 30-170, 40-100, 40-150, 40-160, 40-170, 50-100, 50-150, 50-160, 50-170, 100-125, 100-150 or 100-160 consecutive amino acid residues.

The isolated or recombinant amino acid sequence or isolated or recombinant protein in I) comprising the sequence set forth in SEQ ID NO: 7 may preferably comprise a total of from 521-670 consequtive amino acid residues, such as from 521-651, from 521-631, from 521-611, from 521-591, from 521-571, from 521- 551 or from 521-531 consecutive amino acid residues. In particular, the isolated or recombinant amino acid sequence or isolated or recombinant protein in I) may in addition to the sequence set forth in SEQ ID NO: 7 comprise amino acid residues 900-920 of SEQ ID NO: 5, such as amino acid residues 880-920, amino acid residues 860-920, amino acid residues 840-920, amino acid residues 820- 920, amino acid residues 800-920, amino acid residues 780-920 or amino acid residues 760-920 of SEQ ID NO: 5.

By analogy, the isolated or recombinant amino acid sequence or isolated or recombinant protein in I) comprising the sequence set forth in SEQ ID NO: 8 may preferably comprise a total of from 170-650 consequtive amino acid residues, such as from 170-600, from 170-550, from 170-500, from 170-450, from 170- 400, from 170-350, from 170-330, from 170-310, from 170-290, from 170-270, from 170-250, from 170-230, from 170-210 or from 170-190 consecutive amino acid residues. In particular, it may further comprise amino acid residues 900-909 of SEQ ID NO: 5, such as amino acid residues 880-909, amino acid residues 860- 909, amino acid residues 840-909, amino acid residues 820-909, amino acid residues 800-909, amino acid residues 780-909 or amino acid residues 760-909 of SEQ ID NO: 5. The isolated or recombinant amino acid sequence or isolated or recombinant protein in I) comprising the sequence set forth in SEQ ID NO: 8 may further comprise amino acid residues 1081-1090 of SEQ ID NO: 5, such as amino acid residues 1081-1110, amino acid residues 1081-1130, amino acid residues 1081- 5 1150, amino acid residues 1081-1170, amino acid residues 1081-1190, amino acid residues 1081-1210, amino acid residues 1081-1230, amino acid residues 1081-1250, amino acid residues 1081-1270, amino acid residues 1081-1290, amino acid residues 1081-1310, amino acid residues 1081-1350, amino acid residues 1081-1370, amino acid residues 1081-1390, amino acid residues 1081- 10 1410, or amino acid residues 1081-1430 of SEQ ID NO: 5.

Similarly, the isolated or recombinant amino acid sequence or isolated or recombinant protein comprising the sequence set forth in SEQ ID NO: 9 may preferably comprise a total of from 360-520 consequtive amino acid residues, such as from 360-480, from 360-460, from 360-440, from 360-420, from 360- 15 400, or from 360-480 consecutive amino acid residues. In particular, it may

further comprise amino acid residues 1060-1080 of SEQ ID NO: 5, such as amino acid residues 1040-1080, amino acid residues 1020-1080, amino acid residues 1000-1080, amino acid residues 980-1080, amino acid residues 960-1080, amino acid residues 940-1080 or amino acid residues 920-1080 of SEQ ID NO: 5.

20 In particular embodiments the said isolated or recombinant amino acid sequence and/or the said isolated or recombinant protein and/or the said subsequences are immunogenic. The invention in particular relates to a subsequence of the amino acid sequences set forth in any one of SEQ ID NOs: 5-9, wherein said

subsequence is immunogenic.

25 Particularly preferred subsequences according to the present invention include a subsequence of the putative P-domain of coat protein comprising amino acid residues 1081-1250 of SEQ ID NO: 5, and a subsequence of the putative P- domain of coat protein comprising amino acid residues 1175-1441 of SEQ ID NO: 5.

30 The invention also provides an antibody, which is raised against an amino acid sequence as defined above. It is to be understood that the antibody may be a monoclonal or polyclonal antibody. The invention also relates to an isolated nucleic acid sequence which is

complementary to and/or hybridizes under high stringency cond itions to a nucleic acid sequence as defined above. In particular the sequence may be

complementary to and/or hybrid izes under hig h stringency conditions to a nucleic acid sequence being selected from the group consisting of:

I) The nucleic acid sequence set forth in SEQ ID NO : 1 or SEQ ID NO :

2;

II) A subsequence of the nucleic acid sequence set forth in SEQ ID NO :

1 or SEQ ID NO : 2; and

III) A nucleic acid sequence which is at least 75 % identical, such as at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.8% or 99.9% identical, to any one of the seq uences in I) or II)

As the skilled person will appreciate, high stringency conditions may comprise hybrid ization in a buffer consisting of 6 X SSC, 50 mM Tris-HCL (pH =7.5), 1 mM EDTA, 0.02% PVP, 0.02% Ficoll, 0.02% BSA and 100 Mg/ml denatured salmon sperm DNA, for 48 hours at 65°C, washing in a buffer consisting of 2 X SSC, 0.01% PVP, 0.01% Ficoll, 0.01% BSA for 45 minutes at 37°C, and washing in a buffer consisting of 0. 1 X SSC, for 45 minutes at 50°C.

According to the invention is also provided an immunogenic composition/vaccine comprising :

I) An isolated virus as defined above;

II) An isolated or recombinant amino acid sequence/an isolated or

recombinant protein as defined above;

III) An isolated nucleic acid sequence as defined above; or

IV) A plasmid or vector according to the invention.

The immunogenic composition/vaccine preferably comprises a virus as defined above, and a pharmaceutically acceptable carrier and/or excipient.

The skilled person will acknowledge that, when contemplated for the purpose of eliciting a protective immune response, the composition accord ing to the invention may further comprise an organic adjuvant and/or an inorganic adjuvant. The organic adjuvant is preferably selected from the g roup consisting of: mineral oil, sq ualene (2,6, 10, 15, 19,23-hexamethyl-2,6, 10, 14, 18,22-tetracosahexaene), virosomes, CpG oligodeoxynucleotides and adjuvants based on pharmaceutical oils and purified surfactants, such as the adjuvants sold under the trade name Montanide™. Other examples of adjuvants frequently used in fish and shellfish farming are muramyldipeptides, lipopolysaccharides, several glucans and glycans, mineral oil and Carbopol®. Also adjuvants such as interleukin and glycoproteins may be used . An extensive overview of adjuvants suitable for fish and shellfish vaccines is g iven in the review paper by Jan Raa ( 1996), the content of which is incorporated herein by reference in its entirety.

Useful inorganic adjuvants will be known to the skilled artisan and are described in JC Aguilar and EG Rod rig uez, 2007, Vaccine 25, 3752 - 3762, the content of which is incorporated herein by reference in its entirety.

In particular, the inorganic adjuvant which is optionally included in the

composition according to the invention is selected from the group consisting of AI(OH)₃ (Aluminium hydroxide), Ca₃(P04)₂ (Calcium phosphate), and water un- soluble salts of aluminium, calcium, iron or zirconium .

The vaccine may also comprise a so-called "vehicle". A vehicle is a device to which the antigen adheres, without being covalently bound to it. Such vehicles are i.a. biodegradable nano/micro-particles or -capsules of PLGA (poly-lactide-co-glycolic acid), alginate or chitosan, liposomes, niosomes, micelles, multiple emulsions and macrosols, all known in the art. A special form of such a vehicle, in which the antigen is partially embedded in the vehicle, is the so-called ISCOM (European patents EP 109.942, EP 180.564 and EP 242.380, the content of which is incorporated herein by reference in its entirety) .

In addition, the composition may comprise one or more suitable surface-active compounds, detergents and/or emulsifiers.

In particular, the detergent is selected from the group consisting of non-ionic detergents, cationic detergents and anionic detergents. As the skilled person will realize esters of non-PEG-ylated or PEG-ylated sorbitan with fatty acids are examples of useful emulsifiers. The emulsifier may in particular be polysorbate or sorbitan oleate. More specifically, the said detergent and/or emulsifier may be selected from the group consisting of polyoxyethylene (20) sorbitan monooleate (Tween®80), Sorbitane monooleate (Span®80),

Cremophore, Tween® and Span® . Preferably, the immunogenic composition/vaccine contains a virus according to the invention wherein said virus is either attenuated or inactivated .

As the skilled person will know the virus may be inactivated using several proced ures known in the art, such as by chemical or physical means. Chemical inactivation may for instance be carried out by treatment of the virus with enzymes, with formaldehyde, β-propiolactone or ethyleneimine or a derivative thereof, with organic solvent (e.g . 30 halogenated hydrocarbon) and/or detergent, e.g . Triton® or Tween®. Physiolog ical inactivation can advantageously be carried out by subjecting the viruses to energy-rich radiation, such as UV light, gamma irradiation or X-rays. For the present purpose, the immunogenic

composition/vaccine preferably contains virus according to the invention, wherein said virus has been inactivated by treatment with formalin .

Preferably, the immunogenic composition/vaccine contains virus, wherein said virus is formulated in a water-in-oil emulsion.

In preferred embod iments the immunogenic composition is a recombinant vaccine comprising one or more amino acid seq uences according to the invention.

In particular preferred embodiments the recombinant vaccine comprises one or moren amino acid sequence selected from the group consisting of:

I) The amino acid sequence set forth in SEQ ID NO : 5 and/or an amino acid sequence contained within SEQ ID NO : 5, selected from the group consisting of the amino acid sequences set forth in any of SEQ ID NOs : 6-9;

Π) A subsequence of any of the amino acid sequences in I) ;

III) An amino acid sequence which is at least 75% identical to any one of the sequences in I) or II), such as an amino acid seq uence which has been derived from any of said seq uences in I) or II) by deletion, add ition and/or mod ification of one or more amino acid residues. In particular embodiments the said isolated or recombinant amino acid sequence and/or the said isolated or recombinant protein and/or the said subsequences are immunogenic. The invention in particular relates to vaccine wherein the

subsequence of the amino acid sequences set forth in any of SEQ ID NOs: 5-9 is immunogenic.

Particularly preferred vaccines according to the present invention comprise a subsequence of the putative P-domain of the coat protein comprising amino acid residues 1081-1250 of SEQ ID NO: 5, and/or a subsequence of the putative P- domain of the coat protein (comprising amino acid residues 1175-1441 of SEQ ID NO: 5).

According to further embodiments, the vaccine comprises a subsequences of the amino acid in I) in combination with an amino acid sequences as defined in III).

In still further embodiments, the vaccine comprises multiple subsequences of the amino acid in I) and/or multiple amino acid sequences as defined in III). Such recombinant vaccines may be prepared using standard procedures known in the art.

According to certain embodiments the immunogenic composition/vaccine comprises virus or one or more isolated or recombinant amino acid sequences or proteins according to the invention wherein said virus or said isolated or recombinant amino acid sequence(s) or proteins is/are combined with other immunologic agents. The skilled person will realize the potential advantage of such polyvalent vaccines.

The invention further provides a method of detecting a virus as described above in a sample, comprising contacting said sample with a nucleic acid sequence; or with an antibody as described above.

A further aspect of the invention provides a diagnostic kit comprising a nucleic acid sequence as described above; or an antibody according to the invention.

The invention also relates to a method of manufacturing an immunogenic composition or vaccine as described above, said method comprising : I) Growing a virus as defined above in a cell culture, such as until a cytopathogenic effect is observed

II) Harvesting the virus; and

III) Optionally inactivating the virus. According to further aspects the invention provide a virus as defined above, an isolated nucleic acid sequence, or an isolated or recombinant amino acid

sequence/an isolated or recombinant protein as defined above for use in medicine. In particular, said virus, said isolated nucleic acid sequence, and said isolated or recombinant amino acid sequence/isolated or recombinant protein may be for use in preventing infections with salmonid caiicivirus or reducing the incidence of such infections, or for treatment of such infections.

Further aspects of the invention provide the use of a virus, an isolated nucleic acid sequence, or an isolated or recombinant amino acid sequence/an isolated or recombinant protein as defined above for the manufacture of an immunological composition for preventing infections with salmonid caiicivirus or reducing the incidence of such infections, or for treatment of such infections.

Even further aspects of the invention pertain to a method for preventing, treating or reducing the incidence of infections with salmonid caiicivirus comprising identifying an individual which is infected or is at risk of becoming infected with said virus; and administering to said individual virus, an isolated nucleic acid sequence, or an isolated or recombinant amino acid sequence/an isolated or recombinant protein as defined above.

It should be noted that embodiments and features described in the context of one of the aspects of the present invention also apply to the other aspects of the invention.

All patent and non-patent references cited in the present application, are hereby incorporated by reference in their entirety.

The invention will now be described in further details in the following non-limiting examples. Examples

Example 1 : Isolation of salmonid calicivirus

GF-1 cell cultures were grown in L-15 (Sigma) with 10% foetal bovine serum (FBS, Gibco), 1% glutamine (Sigma) and 0,1% gentamicin (Sigma). GF-1 cells were seeded at a desity of 3,5E4 GF-1 cells per cm² and infected with heart homogenates from farmed Atlantic salmon in Norway experiencing undiagnosed disease with heart pathology.

The homogenate was prepared by homogenizing heart tissue with ca 5 ml cell culture medium and quartz sand with a pistil in a mortar. The homogenate was centrifuged at 1000 x g for 5 minutes in a centrifuge, the supernatant removed and passed through a 0.45 Mm filter. 0.1 ml filtered supernatant was added to a 75 cm² cell culture flask. After 28 days of incubation at 15°C, a mild

cytopathogenic effect was observed with the cell layer displaying reduced growth and some rounding up of cells. 0.5 ml supernatant from this culture was transferred to a new 75cm² cell flask with GF-1 cells, and the same type of cpe was observed 28 days after inoculation. New naive GF-1 cells were infected with 1/3 inoculate from these flasks + 2/3 of fresh medium, and a stronger cpe of the same type was observed.

Images of GF-1 cells infected with 33% cell culture medium from cells displaying cpe. 17 days after infection and GF-1 control cells, not infected, are shown in figure 2(A) and (B), respectively.

Example 2: Cloning and sequencing of a nucleotide sequence from the genome of salmonid calicivirus isolate A2-G01 Total RNA was isolated from calicivirus-infected GF-1 cells showing CPE or PD- infected GF-1 cells using Trizol LS according to manufacturers protocol. _AII RNAs were DNase treated using Turbo DNA-free™ kit (Ambion), followed by routine DNase treatment using 10 Mg RNA in a 50 μΙ reaction. RNA integrity of all RNA isolations (no degradation products) were verified by Bioanalyzer analysis. _AII measurements of RNA concentrations were made by Picodrop spectrophotometry (Picodrop Limited, Saffron Walden, UK).

96 different hexamer primers that had been shown to rarely prime rRNA but did prime all known mammalian viruses (D. Endoh, et.al., 2005, Nucleic Acid

5 Research, Vol 33, No.6) were ordered and mixed to a concentration of 0.36 ug/ul.

Double-stranded (ds) cDNA was synthesized using "Superscript double-stranded cDNA synthesis kit" from Invitrogen, applying lul of 0.36 ug/ul "non-ribosomal" random hexamer primers for first strand synthesis. 1 Mg of totalRNA was used in first strand synthesis.

10 Representational difference analysis (RDA)

RDA was performed according to a modified protocol by Pastorian, K. et.al.

(Analytical Biochemistry 283, 89-98 (2000)). Both forward and reverse RDA were performed, one of which PD-infected GF-1 cells served as the driver, and one of which the calicivirus infected GF-1 cells served as the driver.

15 Driver cDNA was made accordingly:

Concentrations of dsCDNAs were measured before the dscDNAs were digested by DPN II and purified. Purified restriction cut dscDNA were subsequently ligated to 24mer I, and amplified by PCR. An optimal number of amplification cycles were identified for each cDNA to avoid "over-amplification", and thus that just a few 20 cDNAs "take over" the PCR reactions. Amplified cDNAs were subsequently

purified, digested, and purified again before concentrations were measured.

Tester cDNA for hybridization round I was made by ligation of 0.2 ug of driver cDNA to RDA 24mer II.

Hybridization round I was performed according to Pastorian, K. et.al., at a ratio of 25 1 : 500 tester: driver. After hybridization, two optimalized rounds of PCR were

performed according to Pastorian, K. et.al., before purification, DPN II digestion, and purification again. Subtracted, purified, restriction cut amplified tester from Hybridization I was then subjected to two more rounds of hybridization at the ratios 1 : 5000 (hyb II), and 1 : 50000 (hyb III), by ligation to adapters/primers 30 24mer III and 24mer IV. All PCR reactions were visualized by gel electrophoresis. Resulting cDNAs (after three rounds of hybridizations) were transformed into Topo TA vectors from Invitrogen and sequenced.

Several clones were obtained from the RDA experiment. The sequences were BLASTed and primers were designed for unknown sequences. The primers were used to screen the clones for sequences that were present in cells having been infected with the virus, but not in uninfected cells. The primers that were found to produce a PCR product from virus cultures (primers for clones A2, A8, C3, E12 and G01, see figure 1) were then combined to find the chronology of the sequences. Primers E12-forward together with C3-forward (E12fC3f) produced a band of about 1.5 kb. Likewise, A2f-E12r produced a band of 2,5-3 kb, and GOlf- C3r produced a product of 600 bp. No match was found for the A8 clone. The obtained PCR-products were all cloned and sequenced. The sequences of the A2, E12, C3 and G01 clones were retrieved in the products of these primer

combinations, serving as a good control for the specificity of the PCR (i.e the A2 clone sequence was found in the 5'-end and the E12 sequence was found in the 3'end of the A2fE12r PCR products and so forth). The PCR analysis and the sequencing suggested that the clones were in the order A2, E12, C3, G01. To test the robustness of this approach a PCR reaction with relevant primer combinations (G01fA2f, GOlf, E12f, G01fC3r, A2fE12r and A2fC3f) that would amplify long products were set up. The longest band produced was E12fG01f. The lack of a A2- G01 band was most likely due to technical problems. The E12fG01f PCR product was cloned and sequenced and found to contain the C3 clone and confirmed that the E12-C3-G01 sequence was correct. Now, a continuous sequence of 4472 bp (SEQ ID NO: 1) had been identified. By DNA analysis software (pDRAW,

Acaclone), one long open reading frame was found. By running BLAST on the sequence, putative regions were identified, such as a domain with Peptidase homology, a domain with calicivirus RdRp homology and a domain with virus coat homology. On the basis of this sequence, one primer pair in the RdRp region, and two primer pairs in the coat region were constructed. These primer pairs were used to screen field samples for the presence of this virus. The virus sequences were indeed found in field samples. To indentify the remaining sequences of the virus, 3'RACE and 5'RACE was performed. The 3' RACE ready cDNA was produced using a oligo(dT)-primer with a 22 bp tag. The 3'RACE PCR product was produced using the GOlr primer and a primer recognizing the tag. A product of about 400 bp was obtained, cloned and sequenced. The sequence contained the G01 clone sequence followed by new 3' sequence and a poly(A) tail. The final virus sequence after 3'RACE is 4759 bp (SEQ ID NO: 2).

Table 2: Primer sequences

Example 3 : Detection of salmonid calicivirus in Atlantic salmon by Real Time PCR

Tissue samples from heart were collected from a clinical trial and from cages in a commercial salmon farm.

1. Clinical trial : In the clinical trial, fish were injected with salmonid calicivirus grown as described in example 1. The fish were held in salt water, 12°C. Sampling was done before challenge, and 1,4,8 and 11 weeks after challenge of the fish. The tip of the heart ventricle and mid kidney was removed aseptically, and transferred to RNAIater (Ambion). Following RNA isolation with standard

procedures, total RNA (800ng) was reverse transcribed into cDNA and real-time PCR was performed, both using Superscript™ III Platinum® Two-Step qRT-PCR Kit with SYBR® Green (Invitrogen) according to the manufacturer's instructions. The reaction conditions were UDG-incubation at 50°C for 2 minutes, activation of the hot-start polymerase at 95°C for 2 minutes, followed by 40-45 cycles of 95°C for 15 seconds, primer annealing for 15 seconds and extension for 1 min at 60 °C. Melting curve analysis was performed to confirm formation of expected PCR products, and results are presented as Ct-values. PCR primers were A2 forward : GTACACCACCCTGGTTGAGG and A2 reverse: CAGCGACAGCCTTCTGAACT. weeks

post

Fish nr challenge Challenge Organ Heart Kidney

1 0 Injected Heart Negative Negative

2 Negative Negative

3 Negative Negative

4 Negative Negative

25 1 Injected Heart 30,92 29,31

26 28,2 28,22

27 29,52 30,15

28 39,01 28,65

49 4 Injected Heart 29,11 28,82

50 28,05 27,65

51 30,74 28,79

52 28,74 28,76

73 8 Injected Heart 32,58 28,15

74 31,65 28,35

75 30,94 27,97

76 32,18 29,32

121 11 Injected Heart Negative 29,37

122 32,69 27,81

123 30,31 25,77

124 33,69 28,72

These result show that Real Time RT-PCR is a suitable method for detection of salmonid calicivirus in tissue samples from fish. 2. Field samples: Heart samples were collected on RNAIater from 20 farms experiencing disease problems related to unspecific clinical signs and heart pathology. Following RNA isolation with standard procedures, total RNA (800ng) was reverse transcribed into cDNA and real-time PCR was performed, both using Superscript™ III Platinum® Two-Step q RT-PCR Kit with SYBR® Green

(Invitrogen) according to the manufacturer's instructions. The reaction conditions were UDG-incubation at 50°C for 2 minutes, activation of the hot-start polymerase at 95°C for 2 minutes, followed by 40-45 cycles of 95°C for 15 seconds, primer annealing for 15 seconds and extension for 1 min at 60°C. Melting curve analysis was performed to confirm formation of expected PCR products, and results are presented as Ct-values. PCR primers were forward: GTTCCTGGTGGCCTACTTCC (SEQ ID NO: 19) and A2 reverse: ACATTGCCACTGTTGCCAGCC (SEQ ID NO: 20). Of the 20 farms tested, 5 were positive for salmon calicivirus.

Example 4. Phylogenetic analysis

The nucleotide sequence of salmonid calicivirus was subjected to bioinformatic analysis to infer its relationship to other caliciviruses. First, the amino acid sequence of the polyprotein was translated from the identified ORF using the Expasy translate tool. Conserved domains showing significant identity to RNA helicase, protease, RNA dependent RNA polymerase and calicivirus capsid proteins were identified in the polyprotein by Blast analysis.

Phylogenetic analysis was performed on the individual domains that were identified in the polyprotein by Blast analysis, the RNA helicase, the protease, the RNA dependent RNA polymerase and the capsid. In these analyses, the alignment was cropped to contain only the conserved domains identified by the initial Blast analysis. The model of substitution was chosen independently for each analysis using Model Selection with the Bayes Information Criterion in MEGA. In the phylogenetic analysis, the salmon calicivirus is named PHARMAQ calicivirus.

The phylogenetic trees are shown in figures 5-9.

Example 5: Vaccination with an inactivated virus from isolate A2-G01.

Preparation of vaccine: Salmonid calicivirus was grown as described in example 1 in a 632 cm² flask with 30000 GF-1 cells/cm², 155 ml medium and 25 ml inoculate prepared as described in example 1. Supernatant was harvested 28 days after inoculation, formalin added to 2% and incubated at 15°C for 72 hours. Inactivated virus was pelleted by centrifugation at 100,000 xg for 4 hours, and resuspended in 6 ml PBS. 5ml of this was formulated in a total of 50 ml water-in-oil emulsion.

Fish were vaccinated with a 0.1 ml dose of vaccine. 500 degree days after vaccination, the fish were challenged intraperitoneally with virus grown as described in example 1. Sampling was done before challenge, and 1,8 and 11 weeks after challenge of the fish. The tip of the heart ventricle and mid kidney was removed aseptically, and transferred to RNAIater (Ambion). Following RNA isolation with standard procedures, total RNA (800ng) was reverse transcribed into cDNA and real-time PCR was performed, both using Superscript™ III Platinum® Two-Step qRT-PCR Kit with SYBR® Green (Invitrogen) according to the manufacturer's instructions. The reaction conditions were UDG-incubation at 50°C for 2 minutes, activation of the hot-start polymerase at 95°C for 2 minutes, followed by 40-45 cycles of 95°C for 15 seconds, primer annealing for 15 seconds and extension for 1 min at 60°C. Melting curve analysis was performed to confirm formation of expected PCR products, and results are presented as Ct-values. PCR primers were A2 forward : GTACACCACCCTGGTTGAGG and A2 reverse:

CAGCGACAGCCTTCTGAACT

Fish nr WPC Heart Kidney Average

1 0 Unvaccinated Negative Negative

2 Negative Negative

3 Negative Negative

4 Negative Negative

73 8 Unvaccinated 32,58 28, 15 28,4

74 31,65 28,35

75 30,94 27,97

76 32, 18 29,32

121 11 Unvaccinated Negative 29,37 27,9

122 32,69 27,81

123 30,31 25,77

124 33,69 28,72

97 8 Vaccinated Negative 32,54 32,3

98 Negative Negative

99 Negative 31,03

100 Negative 33,22

145 11 Vaccinated Negative 32,42 32,0

146 Negative 31,99

147 Negative 31,87

148 Negative 31,8 In the non-vaccinated controls, salmonid calicivirus was detected in both heart and kidney at all sampling time points. In the vaccinated g roup, virus was only detected in the kidney, and with higher Ct values than in the control group. The detected virus in the kid ney may be orig inating from the vaccine, or may be a low amount of virus having replicated in the kidney. This experiment shows that the vaccine with inactivate virus has protected the fish against a challenge with salmonid calicivirus. Example 6 : Vaccination with an inactivated variant of viral isolate A2-G01.

Virus from isolate A2-G01 are cultured in serial passages on GF- 1 cells, in a total of 12 passages.

For preparation of the vaccine the virus is grown, harvested, inactivated and formulated in a water-in-oil emulsion as described in example 4. Fish are vaccinated, subsequently challenged intraperitoneally with virus.

Detection of virus infection is performed essentially as described in example 4

Example 7 : Identification of immunogenic reg ions within the amino acid sequence of the coat protein of salmonid callicivirus :

The amino acid of the coat domain from salmon calicivirus isolate A2-G01 was aligned with coat domains from other calici viruses, including Southampton virus, Norwalk virus, Feline calicivirus, Rabbit hemorrhagic disease virus, Porcine enteric sapovirus, Calicivirus NB, Newbury agent 1, Sapporo virus, European brown hare synd rome virus, San Miguel sea lion virus, Human calicivirus, Murine norovirus 1, Tulane virus and Feline calicivirus. By the alig nment several conserved residues were identified . The conserved residues are expected to be important features of the coat protein, and are found within part of the S-domain which is the best conserved part of the coat protein . Identification of the conserved resid ues in the S-domain by alignment is shown in Figure 4. A review of the literature on calicivirus has revealed that, generally, the majority of the neutralizing epitopes are located in the P-domain, Hence, the P-domain is expected to be the best choice for a recombinant protein vaccine. The putative P- domain of salmon calicivirus is set forth in SEQ ID NO : 9.

Example 8 : Preparation of antibodies/antisera

Preparation of monoclonal antibod ies

BALBc mice are immunized with purified salmon calicivirus. Using Indirect

Fluorescent Antibody test (IFA) with calicivirus-infected GF- 1 cells, antiviral antibodies are evaluated in sera collected 15 days after the second immunization . Seropositive mice, which show a high titre of antibodies against salmon calicivirus, are inoculated with the purified salmon calicivirus by the intravenous route as the third immunization . Subsq uently, spleen cells of the mice are taken out and fused with myeloma cells. Hybridomas secreting antibodies against calicivirus are detected by IFA and a neutralization test against calicivirus. Cultures producing virus-specific antibodies are subcloned by limiting d ilution, followed by recloning and preparation of ascetic fluid . Preparation of antisera against coat protein

A nucleic acid sequence encod ing the putative coat protein is cloned into an expression vector and is subsequently expressed in a protein expression system. The polypeptide is purified and injected into mice or rabbits. Sera obtained from the animals are inactivated and stored at -20°C until used . Example 9 : Preparation of salmon calicivirus recombinant vaccines

For the purpose of vaccination the following recombinant polypeptides are provided :

1) Coat protein, comprising amino acid residues residues 920- 1441 of SEQ ID NO : 5

2) Sequence from the putative P-domain of coat protein (comprising amino acid residues 1081- 1441 of SEQ ID NO : 5)

3) Sequence from the putative S-domain of coat protein (comprising amino acid residues 911 - 1081 of SEQ ID NO : 5)

4) Subsequence of the putative P-domain of coat protein (comprising amino acid residues 1081- 1250 of SEQ ID NO : 5) 5) Subsequence of the putative P-domain of coat protein (comprising amino acid residues 1175-1441 of SEQ ID NO: 5)

6) Subsequence of the coat protein (comprising amino acid residues residues 990-1375 of SEQ ID NO: 5)

The polypeptides are cloned into expression vectors and expressed in a protein expression system. Each polypeptide is purified, and formulated as a water-in-oil emulsion.

Example 10: Vaccination and challenge of Atlantic salmon with salmon calicivirus

The aim of this study is to assess the effect of vaccines based on recombinant coat proteins from salmon calicivirus.

Atlantic salmon are vaccinated by intraperitoneal vaccination with the vaccines described in example 4. Vaccine efficacy is tested through i.p. challenge of vaccinated and unvaccinated Atlantic salmon. Tissue samples from vaccinated and unvaccinated fish will be collected for histopathological evaluation and PCR- screening.

Mortality is registered daily and tissue samples are collected at different time points from the vaccinated and unvaccinated group for histopathological evaluation and PCR-screening.

References

1. Smith AW, Boyt PM J Zoo Wildlife Med 1990;21 : 3-23

2. Berke et al., J Med Viroll997 Aug 52(4) 419-424

3. Smith et al. Diseases of Aquatic organisms 1986;2: 73-80

4. Rognes T (2001), ParAlign : a parallel sequence alignment algorithm for rapid and sensitive database searches, Nucleic Acids Research, 29, 1647-1652 2001.

5. Smith TF and Waterman MS (1981) Journal of Molecular Biology, 147, 195-197.

6. Watson JD, Hopkins NH, Roberts JW, Steitz JA, Weiner AM (1987)

Molecular biology of the gene, Chapter 24 The extraordinary diversity of eucaryotic viruses (898-961).

7. Elena, SF and Sanjuan, R et al. (2005), Journal of Virology, 79, 11555-11558.

8. Pastorian, K. et al. (2000) Analytical Biochemistry 283, 89-98.

9. Endoh, D. et al., (2005), Nucleic Acid Research, Vol 33, No.6.

10. Raa, J. (1996), Reviews in Fisheries Science 4(3) : 229-228. 11. Aguilar, JC and Rodriguez, EG, (2007), Vaccine 25, 3752 - 3762. 12. Cothia et al. (1986) EMBO j., vol 5, 4, pp. 823-826.

Claims

An isolated non-enveloped, positive stranded RNA virus, wherein said virus is selected from the group consisting of:

III) the viral isolate A2-G01 deposited under the Budapest Treaty with the European Collection of Cell culture (ECACC), Health Protection Agency, Porton Down, Salisbury, Wiltshire (UK), SP4 OJG UK on January 7 2010 under deposit number 10010701; and

IV) a virus which is related to the viral isolate in I) and which comprises in its genome a ribonucleic acid sequence which by reverse transcription and 2^nd strand synthesis provides a sequence which is at least 65 % identical to the sequence set forth in SEQ ID NO: 1, and/or is at least least 65 % identical to the sequence set forth in SEQ ID NO: 2.

An isolated non-enveloped, positive stranded RNA virus, wherein the genome of said virus comprises an open reading frame encoding a sequence selected from the group consisting of

I) The amino acid sequence set forth in any of SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8 and/or SEQ ID NO: 9

II) An amino acid sequence which is at least 75% identical, to any of the sequence in I), such as an amino acid sequence which has been derived from said sequence in I) by deletion, addition and/or modification of one or more amino acid residues.

The virus according to claim 1 or 2, wherein the genome of said virus encodes an RNA-dependent RNA polymerase comprising an amino acid sequence selected from the group consisting of

I) The amino acid sequence set forth in SEQ ID NO: 6;

II) An amino acid sequence which is at least 75% identical, identical, to the sequence in I) , such as an amino acid sequence which has been derived from said sequence in I) by deletion, addition and/or modification of one or more amino acid residues. The virus according to claim 1 or 2, wherein the genome of said virus encodes a coat protein having an amino acid sequence selected from the group consisting of

I) The amino acid sequence set forth in SEQ ID NO: 5, SEQ ID NO: 7 and/or SEQ ID NO: 9;

II) An amino acid sequence which is at least 75% identicalto the

sequence in I), such as an amino acid sequence which has been derived from said sequence in I) by deletion, addition and/or modification of one or more amino acid residues.

The virus according to any of the preceding claims, said virus being an attenuated or inactivated virus.

The virus according to any of the preceding claims, wherein said virus is obtainable by growing viral isolate A2-G01 as deposited under deposit number 10010701 on a cell culture, such as for one or more passages and/or until a cytopathogenic effect is obtained.

The virus according to any of the preceding claims, said virus being capable of binding to an antibody which is raised against viral isolate A2-G01 as deposited under deposit number 10010701 and/or is raised against an amino acid sequence as defined in claim 2, 3 or 4.

An isolated nucleic acid sequence encoding an amino acid sequence as defined in any of claims 2 to 4.

The isolated nucleic acid sequence according to claim 8, said nucleic acid sequence comprising or consisting of a sequence selected from the group consisting of:

I) The nucleic acid sequence set forth in SEQ ID NO: 1 and/or SEQ ID NO: 2;

II) A subsequence of the nucleic acid sequence set forth in SEQ ID NO:

1 or in SEQ ID NO: 2; and

III) A nucleic acid sequence which is at least 75% identical, to any one of the sequences in I) or II). The isolated nucleic acid sequence according to claim 9 in which said subsequence in II) is selected form the group consisting of:

i) a sequence comprising nucleic acid residues 1568-2377 of the

sequence set forth in SEQ ID NO : 1 or SEQ ID NO: 3; corresponding to nucleic acid residues 4241-5051 of the sequence set forth in SEQ ID NO: 2 or SEQ ID NO : 4 (sequence encoding SEQ ID NO : 6); and ii) a sequence comprising nucleic acid residues 2842-3355 of the

sequence set forth in SEQ ID NO: 1 or SEQ ID NO: 3; corresponding to nucleic acid residues 5517-6029 of the sequence set forth in SEQ ID NO: 2 or SEQ ID NO : 4 (sequence encoding SEQ ID NO : 8);

iii) a sequence comprising nucleic acid residues 2872-4435 of the

sequence set forth in SEQ ID NO: 1 or SEQ ID NO : 3; corresponding to nucleic acid residues of the sequence set forth in SEQ ID NO: 2 or SEQ ID NO : 4 (sequence encoding SEQ ID NO : 7); iv) a sequence comprising nucleic acid residues 3356-4435 of the

sequence set forth in SEQ ID NO: 1 or SEQ ID NO : 3; corresponding to nucleic acid residues 5547-7109 of the sequence set forth in SEQ ID NO: 2 or SEQ ID NO : 4 (sequence encoding SEQ ID NO : 9);

v) a sequence comprising nucleic acid residues 3356-3862 of the sequence set forth in SEQ ID NO: 1 or SEQ ID NO: 3; corresponding to nucleic acid residues 5547-6536 of the sequence set forth in SEQ ID NO: 2 or SEQ ID NO : 4 (sequence encoding amino acid residues 1081-1250 of SEQ ID NO : 5); and

vi) a sequence comprising nucleic acid residues 3637-4435 of the sequence set forth in SEQ ID NO : 1 or SEQ ID NO: 3; corresponding to nucleic acid residues 6311-7109 of the sequence set forth in SEQ ID NO: 2 or SEQ ID NO : 4 (sequence encoding amino acid residues 1175-1441 of SEQ ID NO: 5).

11. Vector comprising a nucleic acid sequence according to any of claims 8 to 10.

12. A host cell comprising the isolated nucleic acid sequence according to any of claims 8 to 10; and/or the vector according to claim 11.

13. An isolated or recombinant amino acid sequence/an isolated or recombinant protein comprising or consisting of one or more sequences selected from the group consisting of

I) The amino acid sequence set forth in SEQ ID NO: 5, and an amino acid sequence contained within SEQ ID NO: 5, selected from the group consisting of the amino acid sequences set forth in any of SEQ ID NOs: 6-9;

II) A subsequence of any one of the amino acid sequences in I);

III) An amino acid sequence which is at least 75% identical to the

sequences in I) or II), such as an amino acid sequence which has been derived from any of said sequences in I) or II) by deletion, addition and/or modification of one or more amino acid residues.

14. An antibody, which is raised against an amino acid sequence as defined in claim 2, 3 or 4.

An isolated nucleic acid sequence which is complementary to and/or hybridizes under high stringency conditions to a sequence defined in any of claims 8 to 10.

16. The isolated nucleic acid sequence according to claim 15, wherein said high stringency conditions comprise hybridization in a buffer consisting of 6 X SSC, 50 mM Tris-HCL (pH = 7.5), 1 mM EDTA, 0.02% PVP, 0.02% Ficoll, 0.02% BSA and 100 g/ml denatured salmon sperm DNA, for 48 hours at 65°C, washing in a buffer consisting of 2 X SSC, 0.01% PVP, 0.01% Ficoll, 0.01% BSA for 45 minutes at 37°C, and washing in a buffer consisting of 0.1 X SSC, for 45 minutes at 50°C.

An immunogenic composition/vaccine comprising :

I) An isolated virus as defined in any of claims 1 to 7;

II) An isolated or recombinant amino acid sequence/an isolated or

recombinant protein as defined in claim 13; III) An isolated nucleic acid sequence as defined in any of claims 8 to 10; or

IV) A vector as defined in claim 11.

5 18. The immunogenic composition/vaccine according to claim 17 comprising a virus as defined in any of claims 1 to 7, and a pharmaceutically acceptable carrier.

19. The immunogenic composition/vaccine according to claim 17 or 18, wherein 10 said virus is either attenuated or inactivated.

20. The immunogenic composition/vaccine according to claim 19, wherein said virus has been inactivated by formalin.

15 21. The immunogenic composition/vaccine according to any of claims 18 to 20, wherein said virus is formulated in a water-in-oil emulsion.

22. The immunogenic composition/vaccine according to any of claims 17 to 21, wherein said virus or said isolated or recombinant amino acid sequence or

20 protein is combined with other immunologic agents.

23. A method of detecting a virus according to any of claims 1 to 7 in a sample, comprising contacting said sample with a nucleic acid sequence as described in any of claims 8-10, 15, and 16; or with an antibody as described in claim

25 14.

24. Diagnostic kit comprising a nucleic acid sequence as described in any of

claims 8-10, 15, and 16; or an antibody as described in claim 14.

30 25. A method of manufacturing a vaccine as described in any of claims 18 to 21, said method comprising :

I) Growing a virus as defined in any of claims 1-7 in a cell culture, such as until a cytopathogenic effect is observed

II) Harvesting the virus; and

35 III) Optionally inactivating the virus.

26. A virus as defined in any of claims 1 to 7, an isolated nucleic acid sequence according to any of claims 8-10, or an isolated or recombinant amino acid sequence/an isolated or recombinant protein as defined in claim 13 for use in medicine.

27. Use of a virus as defined in any of claims 1 to 7, an isolated nucleic acid

sequence according to any of claims 8-10, or an isolated or recombinant amino acid sequence/an isolated or recombinant protein as defined in claim 13 for the manufacture of a immunological composition for preventing infections with salmonid callicivirus or reducing the incidence of such infections, or for treatment of such infections.

28. A method for preventing, treating or reducing the incidence of infections with salmonid callicivirus comprising identifying an individual which is infected or is at risk of becoming infected with said virus; and administering to said individual virus as defined in any of claims 1 to 7, an isolated nucleic acid sequence according to any of claims 810, or an isolated or recombinant amino acid sequence/an isolated or recombinant protein as defined in claim 13.