PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS (PRRSV) - MONOCLONAL-ANTIBODIES DETECT COMMON EPITOPES ON 2 VIRAL-PROTEINS OF EUROPEAN AND US ISOLATES

Sixteen hybridoma cell lines secreting monoclonal antibodies (mAbs) di rected against two dutch isolates of the causative virus of Porcine Re productive and Respiratory Syndrome (PRRSV) were produced. The hybrido ma cells resulted from fusions of SP2/0 myeloma cells with splenocytes of STU mice immunized with purified PRRSV after induction of immunoto lerance against host cell constituents. Screening of supernatant fluid s was performed by an indirect immunofluorescence assay on PRRSV-infec ted porcine alveolar macrophages. Immunoblotting studies revealed that the mAbs had different protein specificities. One mAb reacted with a viral 15 kD protein, eleven were directed against a 40-50 kD protein, and four against a 30-40 kD protein. The mAb against the 15 kD putativ e nucleocapsid protein is well as five mAbs against the 40-50 kD prote in recognized epitopes on these proteins which are conserved in variou s European and U.S. isolates of PRRSV.