Proteins encoded by polynucleic acids of porcine reproductive and respiratory syndrome virus (PRRSV)

Abstract

The present invention provides a purified preparation containing, for example, at least one polypeptide selected from the group consisting of proteins encoded by one or more open reading frames (ORF's) of an Iowa strain of porcine reproductive and respiratory syndrome virus (PRRSV), antigenic regions of such proteins which are at least 5 amino acids in length and which effectively protect a porcine host against a subsequent challenge with a PRRSV isolate, and combinations thereof in which amino acids non-essential for antigenicity may be conservatively substituted. The present invention also concerns a vaccine comprising an effective amount of such a protein; antibodies which specifically bind to such a protein; methods of producing the same; and methods of protecting a pig against a PRRSV, treating a pig infected by a PRRSV, and detecting PRRSV in a pig.

1 . A composition comprising at least one polypeptide selected from the group consisting of:
 proteins encoded by one or more open reading frames (ORF's) of an Iowa strain of porcine reproductive and respiratory syndrome virus (PRRSV);   proteins with at least 99% but less than 100% amino acid homology with proteins encoded by one or more of ORFs 2 of VR 2385 and VR 2474, ORF 3 of VR 2429, and ORFs 4 of VR 2429 and ISU 1894;   proteins with at least 98% but less than 100% amino acid homology with proteins encoded by one or more of ORF 2 of VR 2430 and ORF 5 of VR 2429;   proteins with at least 97% but less than 100% amino acid homology with proteins encoded by one or more of ORF 2 of ISU 1894, ORFs 3 of VR 2474 and ISU 1894, ORF 4 of VR 2474 and ORF 5 of ISU 1894;   proteins with at least 96% but less than 100% amino acid homology with the protein encoded by ORF 4 of VR 2430;   proteins with at least 95% but less than 100% amino acid homology with proteins encoded by one or more of ORF 3 of VR 2430, ORF 4 of VR 2385, and ORF 5 of VR 2474;   proteins with at least 94% but less than 100% amino acid homology with the protein encoded by ORF 2 of VR 2431;   proteins with at least 93% but less than 100% amino acid homology with the protein encoded by ORF 3 of VR 2431;   proteins with at least 92% but less than 100% amino acid homology with the proteins encoded by one or more of ORF 3 of VR 2385 and ORF 5 of VR 2431;   proteins with at least 90% but less than 100% amino acid homology with those encoded by one or more of ORFs 5 of VR 2385 and VR 2430;   proteins with at least 88% but less than 100% amino acid homology with the protein encoded by ORF 3 of VR 2431;   proteins with at least 97% but less than 100% amino acid homology with proteins encoded by one or both of ORF 6 and ORF 7 of an Iowa strain of PRRSV;   and combinations thereof.   
     
     
         2 . The composition of  claim 1 , wherein said polypeptide is encoded by a polynucleic acid sequence selected from the group consisting of the formulas (I), (II), (III) and (IV):
   5′-α-β-3′  (I)     5′-α-β-γ-3′  (II)     5′-α-β-γ-3′  (III)     -5′-α-β-δ-γ-3′  (IV)   
       wherein:
 α encodes at least one polypeptide, low-virulence mutant thereof, or antigenic or low-virulence fragment thereof encoded by a polynucleotide selected from the group consisting of ORFs 2, 3 and 4 of an Iowa strain of PRRSV; 
 β is at least one copy of an ORF 5 from an Iowa strain of PRRSV or one or more hypervariable regions thereof; 
 γ encodes at least one polypeptide encoded by a polynucleotide selected from the group consisting of ORF 6 and ORF 7 of an Iowa strain of PRRSV; and 
 δ is either a covalent bond or a linking polynucleic acid which does not materially affect transcription and/or translation of the polynucleic acid. 
 
     
     
         3 . The composition of  claim 1 , wherein said polypeptide comprises at least one hypervariable region of a protein encoded by an ORF 5 of an Iowa strain of PRRSV. 
     
     
         4 . The composition of  claim 1 , wherein said polypeptide is selected from the group consisting of proteins with at least 97% amino acid homology with proteins encoded by ORF 6 of VR 2385, VR 2429 (ISU-22), ISU-79 and VR 2431 (ISU-3927); proteins with at least 90% amino acid homology with proteins encoded by ORFs 5 of VR 2385 and VR 2430; proteins with at least 94% amino acid homology with the protein encoded by ORF 2, at least 88% amino acid homology with the protein encoded by ORF 3, and at least 93% amino acid homology with the protein encoded by ORF 4 of VR 2431. 
     
     
         5 . The composition of  claim 1 , wherein said polypeptide is encoded by a polynucleic acid selected from the group consisting of ORF 2 of VR 2385, ORF 3 of VR 2385, ORF 4 of VR 2385, ORF 5 of VR 2385, ORF 6 of VR 2385, ORF 7 of VR 2385, ORF 2 of VR 2431, ORF 3 of VR 2431, ORF 4 of VR 2431, ORF 5 of VR 2431, ORF 6 of VR 2431, and ORF 7 of VR 2431. 
     
     
         6 . The purified preparation of  claim 1 , wherein said polypeptide is encoded by a polynucleic acid selected from the group consisting of ORFs 2, 3, 4, 5, 6 and 7 of VR 2385 and VR 2431. 
     
     
         7 . The purified preparation of  claim 1 , wherein said polypeptide is a homologous protein, and non-homologous residues in said homologous protein are conservatively substituted. 
     
     
         8 . A composition comprising a polypeptide encoded by a polynucleic acid having the formula (V):
   5′-ε-ζ-ι-κ-ξ-3′  (V)   
       where:
 κ is a polynucleotide comprising one or more polynucleotides selected from the group consisting of (a) polynucleotide encoding at least one polypeptide encoded by one or more of ORFs 2, 3 and 4 of an Iowa strain of PRRSV; (b) polynucleotide encoding at least one polypeptide encoded by an ORF 5 from an Iowa strain of PRRSV; (c) polynucleotide encoding at least one polypeptide encoded by an ORF 6 or ORF 7 of an Iowa strain of PRRSV; and (d) operationally linked combinations thereof; and wherein κ optionally further comprises a polynucleic acid encoding a conventional marker or a reporter gene; 
 ε, which is optionally present, is a 5′-terminal polynucleotide sequence which provides a means for operationally expressing the polynucleotide κ; 
 ζ is a polynucleotide of the formula KTVACC, where K is T, G or U, and V is A, G or C; 
 ι is a polynucleotide not more than 130 nucleotides in length; 
 and ξ, which is optionally present and when present may be operationally linked to ε, and is a 3′-terminal polynucleotide sequence which does not suppress the operational expression of the polynucleotide κ. 
 
     
     
         9 . An antibody to the polypeptide of  claim 1 . 
     
     
         10 . The antibody of  claim 9 , wherein said antibody is directed to the protein encoded by ORF 5. 
     
     
         11 . The antibody of  claim 10 , wherein said antibody is neutralizing. 
     
     
         12 . The antibody of  claim 11 , wherein said antibody is designated PP5 dB4. 
     
     
         13 . The antibody of  claim 9 , wherein said antibody is directed to the protein encoded by ORF 4. 
     
     
         14 . A method of treating a pig suffering from porcine reproductive and respiratory syndrome, comprising administering an effective amount of the antibody of  claim 12  to a pig in need thereof. 
     
     
         15 . A diagnostic kit for assaying a porcine reproductive and respiratory syndrome virus, comprising the antibody of  claim 12  and a diagnostic agent which indicates a positive immunological reaction with said antibody. 
     
     
         16 . A method of producing a polypeptide, comprising expressing a polynucleic acid encoding the polypeptide of  claim 1  in an operational expression system, and purifying said expressed polypeptide from said expression system.