RESTRICTIVE TYPE OF REPLICATION OF OVINE CAPRINE LENTIVIRUSES IN OVINE FIBROBLAST CELL-CULTURES/

Caprine arthritis-encephalitis virus (CAEV) is a natural lentivirus pa thogen of goats. CAEV, like all members of the ovine/caprine lentiviru s family, has an in vivo tropism for cells of the monocyte/macrophage cell lineage and activation of viral gene expression is observed only following differentiation of monocytes to macrophages. In addition to cells of the monocyte/macrophage lineage, CAEV and the closely related maedi visna virus of sheep (MVV) can also replicate productively in f ibroepithelial cells derived from synovial membrane of goats (GSM). Ho wever, these viruses varied greatly in their ability to replicate in f ibroblasts. We studied the biological and biochemical properties of CA EV and maedi-visna virus (MVV) of sheep following inoculation into the three ovine/caprine cell types. Our data showed no substantial differ ences in virus titers, viral protein biosynthesis, or processing of th e viral proteins between CAEV and MVV following inoculation into prima ry macrophages and GSM cells. However, unlike MW, CAEV failed to repli cate productively in ovine fibroblasts (sheep choroid plexus cells). T his correlated with a specific but abnormal proteolytic cleavage of th e envelope glycoprotein of the virus. This abnormal proteolytic cleava ge represents a novel type of host cell restriction of lentivirus repl ication. (C) 1996 Academic Press, Inc.