A monoclonal antibody-based immunoperoxidase monolayer (micro-isolation) assay for detection of type 1 and type 2 bovine viral diarrhea viruses.

A monoclonal antibody (mAb)-based immunoperoxidase monolayer assay (IPMA) for detection of bovine viral diarrhea virus (BVDV) was developed and compared with an existing bovine polyclonal antibody (pAb)-based IPMA. A pool of 5 mAbs, 4 mAbs produced to a type 1 BVDV and 1 mAb produced to a type 2 BVDV, was utilized in the mAb-IPMA. The mAbs were chosen for inclusion in the pool because of their broad cross-reactivities with type 1 and/or type 2 BVDV, their apparent avidities for antigen, their reactivity to different BVDV proteins, and their lack of competition for binding sites or their binding to unusual BVDV isolates. The mAb-IPMA outperformed the pAb-IPMA in staining, ease of reading test results, and relative sensitivity with a panel of known BVDV positive and negative sera. The relative sensitivities of the mAb-IPMA and pAb-IPMA were 100% and 93.5%, respectively, for 62 positive samples including several that were known to contain type 2 BVDV. With retesting, the pAb-IPMA gave a similar level of sensitivity as that of the mAb-IPMA. Both tests gave a specificity of 100% for 40 negative serum samples obtained from a BVDV-free herd.