Efficient replication of caprine arthritis-encephalitis virus in goat granulosa cells

Recent reports demonstrated the susceptibility of epithelial cells from dif ferent organs to caprine arthritis-encephalitis virus (CAEV) both in vitro and in vivo. Since granulosa cells (GC) are of epithelial origin and curren tly used for in vitro oocyte maturation, we addressed the question whether these cells are susceptible or resistant to CAEV infection. GC were isolate d from goats from certified CAEV-free herds. PCR analysis on GC DNA using C AEV specific primers confirmed the absence of CAEV infection and immunocyto chemistry using specific K813 anti-cytokeratin monoclonal antibodies confir med the epithelial nature of GC. These cells were then inoculated with CAEV using two strains: the CAEV-pBSCA molecular clone and the CAEV-3112 French field isolate. Cytopathic effects (CPE) were observed on cell culture mono layers inoculated with both CAEV strains. Expression of CAEV proteins was s hown both by immunocytochemistry using anti-p24 gag specific antibodies and by immunoprecipitation using an hyperimmune serum. Supernatant of infected cells were shown to contain high titers (ranging 10(5) tissue culture infe ctious doses 50 per ml: TCID50 per ml) of infectious cytopathic viruses whe n assayed onto the indicator goat synovial membrane (GSM) cells. Our findin gs demonstrate the large cell tropism of CAEV and suggest that GC could ser ve as a reservoir for the virus during the sub-clinical phase of infection. Furthermore, given the high seroprevalence of CAEV in the all industrialis ed countries and the large number of ovaries derived from unknown serologic al status animals used for in vitro goat embryo production, one can conclud e that these feeder cell cultures might be a potential source of early tran smission of CAEV to goat embryos. (C) 2001 Elsevier Science B.V. All rights reserved.