Infection of choroid plexus cells by human T cell leukaemia virus type I

Very little is known about the factors that determine the outcome of infection by human T cell leukaemia virus type I (HTLV-I) and the neurotropism of this virus is still a controversial point, In transgenic mice, the HTLV-I LTR is active mainly in the central nervous system (CNS), in parenchyma as well as in ependymal and choroid plexus cells. The latter are of particular interest and could represent the way of entry of the virus into the CNS. In this study we show that primary cultures of sheep choroid plexus can be infected with HTLV-I, leading to characteristic multinucleated syncytial cells containing virus RNA and proteins. HTLV-I p24 Gag protein was detected in the culture medium and the presence of virus particles was observed by electron microscopy 40 days after infection. At this time post-infection HTLV-I could be transmitted to human cord blood cells.