Production and characterisation of monoclonal antibodies to salmon pancreas disease virus

Six mouse monoclonal antibodies (mAbs) specific to salmon pancreas disease virus (SPDV) were produced following immunisation with purified virus prepa rations. These mAbs and 2 mAbs resulting from an earlier investigation were characterised. None of the mAbs possessed virus neutralising activity but all reacted with 4 geographically different SPDV isolates as determined by indirect immunofluorescence. Three mAbs produced positive immunostaining wi th Western blots of SPDV proteins, The 4H1 mAb reacted with the 53 kDa stru ctural E1 glycoprotein present in virus-infected cells and in gradient-puri fied virus. Two mAbs, 5A5 and 7B2, which exhibited unusual immunofluorescen ce staining of the nuclear margin, reacted with a 35 kDa protein, which is present in gradient-purified virus and which is considered to be the capsid protein. A sandwich ELISA, based on the use of mAb 2D9 for capture and a b iotinylated conjugate of mAb 7A2 for detection, detected SPDV antigen in vi rus-infected Chinook salmon embryo-214 cells and gradient-purified virus. T hese mAbs may be of use in pathogenesis studies and in diagnostic test deve lopment.