OVINE AORTIC SMOOTH-MUSCLE CELLS ALLOW THE REPLICATION OF VISNA-MAEDIVIRUS IN-VITRO

Visna-maedi virus induces in sheep an interstitial lung disease charac terised by an accumulation of smooth muscle cells (SMC) or myomatosis. Infection by HIV-1 has been recently associated with disorders of the vessel-derived cells: primary pulmonary hypertension, coronary artery disease and smooth muscle tumors in humans. We hypothesized that, bes ides their regular targets (i.e. macrophages and lymphocytes), lentivi ruses could infect smooth muscle cells. Smooth muscle cell cultures de rived from ovine aorta were infected with visna-maedi virus strain K15 14. The cultured cells were smooth muscle cells as demonstrated by the ir antigenic expression of alpha-actin and vimentin. The lentiviral in fection of the smooth muscle cells was demonstrated by a typical cytop athic effect (syncytia), the expression of virus specific antigens, an d the presence of genomic RNA detected by Northern blot analysis and R T PCR. The detection of a reverse transcriptase activity, the presence of viral RNA in supernatants of infected smooth muscle cells detected by RT PCR and their ability to infect ovine permissive fibroblasts de monstrated a productive infection. The ability of smooth muscle cells to be infected by lentiviruses may participate in the pathogenesis of the tissue damage associated with the lentiviruses such as myomatosis in sheep and vascular disease in humans.