Entry of African swine fever virus into Vero cells and uncoating

African swine fever virus (ASFV) enters Veto cells by adsorptive endocytosis [Valdeira, M.L, Geraldes, A., 1985. Morphological study on the entry of African swine fever virus into cells, Biol. Cell. 55, 35-40]. Electron microscopy of a lysosomotropic drug-controlled penetration indicated that this step takes place in the endosomes, after fusion between the viral envelope and the limiting membrane of the endosome. Inhibition studies with colcemid, cytochalasin B, sodium azide, dinitrophenol, lysosomotropic weak bases, and the ionophore monensin, showed that the virus uptake is largely independent of cytoskeletal and lysosomal function, but dependent on oxidative phosphorylation. Some protease inhibitors inhibited vital replication at an early step, indicating that the initiation of infection depends on a vital proteolytic cleavage.