Peripheral blood mononuclear cells from field cattle immune to bovine viral diarrhea virus (BVDV) are permissive in vitro to BVDV

Abstract

The aim of this study was to determine the in vitro permissivity of peripheral blood mononuclear cells (PBMCs) from bovine viral diarrhea virus (BVDV)-immune field cattle to homologous and heterologous BVDVs. PBMCs from seventeen BVDV-naive and sixteen BVDV-immune animals were infected with noncytopathic BVDV-1 or BVDV-2. The immune status of cattle was indicated by the presence of virus neutralizing antibodies, while viral load of PBMCs was determined by real-time RT-PCR. The results revealed that the PBMCs from naive or immune animals were permissive to either BVDV-1 or BVDV-2, but the viral load was significantly higher for the naive than for the immune animals. Furthermore, the load of homologous virus in PBMCs from immune animals was lower than that of heterologous virus. Our results provide evidence that the PBMCs from BVDV-immune cattle in field are susceptible to reinfection with homologous or heterologous BVDV, albeit to a lower extent in the former case.