Bovine Viral Diarrhea Virus Replication in Bovine Follicular Epithelial Cells Derived from Persistently Infected Heifers

Abstract

Bovine follicle fluid and oocytes surrounded by follicular epithelial (FE) cells were collected from ovaries of two heifers persistently infected with bovine viral diarrhea virus (BVDV). BVDV was present in the follicle fluid at a higher titer than in serum. The oocytes were matured in vitro under culture conditions of 39°C in humidified air containing 5% CO₂. In vitro fertilization was performed after 24 hr in culture (the day of insemination was defined as day l), and culture was continued through day 10. BVDV was present in the culture medium at titers of 10^2.25 to 10^3.25 TC _ID₅₀/0.l ml. The virus was also detected in FE cells collected on day 10. Viral antigen was demonstrated in the cytoplasm of FE cells by the indirect immunofluorescence technique. However, no BVDV was detected in the embryos on day 10. These findings suggested that the oocytes or embryos were unlikely to be infected with BVDV, but that the FE cells were infected with BVDV and supported virus replication in cattle persistently infected with BVDV.