Double-immunolabeling systems for phenotyping of immune cells harboring bovine viral diarrhea virus

Optimal staining conditions were defined for simultaneous detection of bovine viral diarrhea virus (BVDV) and mononuclear leukocyte surface antigens in tissue sections and cytospins. Because of the extreme lability of the virus antigens and the variable stability of the epitopes on the cell differentiation antigens, cryopreservation had to be used. This method gives slightly sub-optimal preservation of morphology. However, the specificity and sensitivity of the immunolabeling ensured reliable identification of the double-labeled cells, i.e., the phenotypic identification of virus-infected cells within the immune system.