Infection of primary cultures of mammary epithelial cells by small ruminant lentiviruses

The caprine arthritis-encephalitis virus (CAEV) and Visna Maedi virus cause persistent infections with long latent periods and induce degenerative and chronic inflammatory lesions of the central nervous system, joints, lungs and udder. Monocyte/macrophage lineage is the main target cell for CAEV and Visna Maedi virus but we speculate that mammary epithelial cells may also be infected. Primary cultures of milk cells, mammary tissues of experimenta lly and naturally infected goats and ewes were used. Primary cultures of ma mmary tissue from ewes and goats were infected with the CAEV Cork strain. T he lentiviral infection of the primary culture was demonstrated by a typica l cytopathic effect in mammary epithelial cells and the presence of an infe ctious virus in coculture with permissive fibroblasts. To identify the epit helial cells in explants and demonstrate the antigenic expression of CAEV, primary cultures were immunostained with polyclonal anti-keratin and monocl onal anti-CAEV p30. Colocalisation studies under a UV fluorescence microsco pe and by epifluorescence microscopy showed the expression of specific vira l antigens in mammary epithelial cells from the eight animals used. Infecte d mammary epithelial cells may act as a reservoir for the virus which may p lay an important role in the virus dissemination and in the pathogenesis of the mammary lentiviral disease. (C) Inra/Elsevier, Paris.