FELINE IMMUNODEFICIENCY VIRUS CAN PRODUCTIVELY INFECT CULTURED ENDOTHELIAL-CELLS FROM CAT BRAIN MICROVESSELS

Feline immunodeficiency virus (FIV) provokes a disease in cats charact erized by histopathological lesions similar to those observed in AIDS patients. In order to determine whether endothelial cells from brain m icrovessels are involved in the central nervous system disease to the same extent as macrophages and microglia, cells were isolated from hea lthy cat brains, cultured and infected in vitro with the FIV Villefran che IFFA 1/88 strain. The isolated cells displayed typical endothelial cell ultrastructural features and were characterized further by von W illebrand factor-labelling and the binding of specific lectins such as Ulex europaeus lectin on their membrane. They were also able to take up acetylated low density lipoproteins. Two weeks after infection, sig nificant amounts of FIV p24 antigen were detected by indirect immunofl uorescence in syncytia and single cells. Concomitantly, the same antig en could be detected in the culture medium of the infected cells by an ELISA technique. Numerous viral particles as well as different steps in the process of viral budding were observed under transmission elect ron microscopy. The synthesis of FIV p24 antigens still occurred in ce lls in which replication was blocked in the G(2) phase with taxol. Our results suggest the possibility of a productive infection of brain mi crovascular endothelial cells by FIV in vivo, which could lead to impo rtant perturbations in the functions of the blood-brain barrier.