Differential immunoassay for prrs vaccine antibody

Abstract

The present invention relates to immunoassays for serologically differentiating animals naturally infected with PRRS virus from animals vaccinated against PRRS. The immunoassays provide detection of at least a portion of the N terminal region of the 2b portion of PRRSV. The immunoassay is preferably an enzyme-linked immunosorbent assay (ELISA).

1 . A method of detecting wild-type PRRSV comprising: obtaining a biological sample from an individual; contacting the biological sample with an antibody that binds at least a portion of the N terminal region of 2b portion of PRRSV to form a complex, said portion including position 9; and assaying said complex. 
     
     
         2 . The method of  claim 1  wherein the PRRSV is free or bound to a carrier molecule or solid support. 
     
     
         3 . The method of  claim 1  wherein the antibody is selected from the group consisting of a polyclonal antibody and a monoclonal antibody. 
     
     
         4 . The method of  claim 1  wherein the biological sample is selected from the group consisting urine, whole blood, plasma, serum, saliva, semen, stool, sputum, cerebral spinal fluid, tears, mucus, tissue, and tissue extract. 
     
     
         5 . The method of  claim 1  wherein the detecting step further includes the substep of linking or incorporating a label into the antibody. 
     
     
         6 . The method of  claim 1  wherein the assaying step uses an immunoassay capable of detecting the antibody to at least a portion of the N terminal region of 2b portion of PRRSV. 
     
     
         7 . The method of  claim 7  wherein the assaying step uses an immunoassay selected from the group consisting of EMIT, radio immunoassay, fluorescent immunoassay, enzyme channeling techniques, and ELISA. 
     
     
         8 . The method of  claim 1  wherein the assaying step uses ELISA-based immunoenzymatic detection. 
     
     
         9 . The method of  claim 6  whereby the portion of the region is a marker at amino acid 9 of the N terminal region of the 2b protein. 
     
     
         10 . The method of  claim 9  whereby the marker is aspartic acid at the 9 th  position of the N terminal region. 
     
     
         11 . An isolated antibody or fragment thereof that specifically binds to at least a portion of the N terminal region of PRRSV protein, said portion including position 9 of the N terminal region. 
     
     
         12 . The isolated antibody or fragment thereof of  claim 10  that binds at least seven amino acids in the N terminal region of PRRSV protein. 
     
     
         13 . The antibody or fragment thereof of  claim 11  that is selected from the group consisting of a polyclonal antibody and a monoclonal antibody. 
     
     
         14 . The antibody or fragment thereof of  claim 11  that is labeled. 
     
     
         15 . The labeled antibody or fragment thereof of  claim 14  wherein the labeled is selected from the group consisting of (a) an enzyme; (b) a fluorescent label; (c) a luminescent label; and (d) a bioluminescent label. 
     
     
         16 . The antibody or fragment thereof of  claim 11  wherein said antibody or fragment thereof specifically binds to said protein in a Western blot. 
     
     
         17 . The antibody or fragment thereof of  claim 11  wherein said antibody or fragment thereof specifically binds to said protein in an ELISA. 
     
     
         18 . The antibody or fragment there of  claim 11  that binds at least the 9th position of the N terminal region. 
     
     
         19 . An isolated cell that produces the antibody or fragment thereof of  claim 11 . 
     
     
         20 . A hybridoma that produces the antibody of  claim 11 . 
     
     
         21 . A method of detecting wild-type PRRSV in a biological sample comprising: (a) contacting the biological sample with the antibody or fragment thereof of  claim 11 ; and (b) detecting the protein in the biological sample. 
     
     
         22 . The method of  claim 21  wherein the antibody or fragment thereof is a polyclonal antibody. 
     
     
         23 . A kit for quantitatively measuring the presence of wild-type PRRSV in a biological sample comprising: a) a biological sample suspected of containing wild-type PRRSV; b) an ELISA plate, said ELISA plate being coated with a carrier protein conjugate; c) antigen-bound antibody, whereby the antigen is specific to at least a portion of the N terminal region of PRRSV 2b protein, said portion including position 9; d) means for labeling the conjugate bound to the antibody; and e) means for measuring the optical signal of the conjugate. 
     
     
         22 . The kit of  claim 21  whereby the biological sample is selected from the group consisting of urine, whole blood, plasma, serum, saliva, semen, stool, sputum, cerebral spinal fluid, tears, mucus, tissue, and tissue extract.