PRODUCTIVE INFECTION OF PRIMARY CULTURES OF ENDOTHELIAL-CELLS FROM THE CAT LIVER SINUSOID WITH THE FELINE IMMUNODEFICIENCY VIRUS

Given the similarities between the two viruses, the feline immunodefic iency virus (FIV) is becoming an interesting animal model for human im munodeficiency virus (HIV) studies. To explore the still controversial role of the liver in the development of HIV infection, sinusoidal end othelial cells (SEC) were isolated, and primary cultures were infected with the FIV Villefranche IFFA strain. The isolated cells were charac terized by their typical fenestrations, the presence of von Willebrand factor (vWf), and their ability to take up acetylated low-density lip oproteins and denatured collagen. Two weeks after infection, significa nt amounts of FIV p24 antigen were detected by immunofluorescence in b oth multinucleated giant and single cells and by enzyme-linked immunos orbent assay in the culture medium. High amounts of viral particles we re observed together with different steps of budding at the plasma mem brane or at the membrane of intracytoplasmic vacuoles. The released vi ral particles were shown to be infectious for a permissive cell line. During the first 3 weeks of infection, the only cytopathic effect of F IV was syncytia formation. No noticeable impairment of the pattern of fenestrations and the modulation of their number by a cytoskeleton-med iated process occurred, The productive infection of SEC may contribute to the progression of the infection.