Epithelial cells from goat oviduct are highly permissive for productive infection with caprine arthritis–encephalitis virus (CAEV)

Abstract

Caprine oviduct epithelial cells (COEC) are commonly used in in vitro goat embryo production protocols to stimulate early embryonic development. These feeder cells are usually collected from slaughterhouses from unknown serological status animals for caprine arthritis–encephalitis virus (CAEV) infection which is frequent in many regions of the world. Tissues derived from this source may be contaminated with CAEV and the use of such material in in vitro fertilisation systems may contribute to transmission of this pathogen to the cultured embryos and dissemination via embryo transfer (ET). The aim of this study was to determine the permissiveness of COEC to CAEV replication in vitro. Cells were isolated from goats from certified CAEV-free herds and then were inoculated with two CAEV strains: the molecularly-cloned isolate of CAEV (CAEV-pBSCA) and the French field isolate (CAEV-3112). Cytopathic effects (CPE) were observed on cell culture monolayers inoculated with both CAEV strains. Expression of CAEV proteins was shown both by immunocytochemistry using anti-p24 gag specific antibodies and by immunoprecipitation using a hyperimmune serum. The CAEV proteins were correctly and properly processed by artificially-infected COEC and the titers of virus released into the supernatant reached 10 6 TCID 50/ml 6 days post-inoculation. Although the macrophage lineage cells are the main centre of infection in the virus-positive animal, these findings suggest that epithelial cells may be important in the viral life cycle probably as a reservoir allowing the viral persistence, dissemination and pathogenesis. These results suggest also that the use in in vitro fertilisation systems of co-culture feeder cells that support efficient replication of CAEV to high titers could represent a serious risk for permanent transmission of virus to the cultured embryos and to the surrogate dam involved.