PROTEIN CELL RECEPTORS MEDIATE THE SATURABLE INTERACTION OF AFRICAN SWINE FEVER VIRUS ATTACHMENT PROTEIN P12 WITH THE SURFACE OF PERMISSIVECELLS

Previous studies have demonstrated that the entry of African swine fev er virus (ASFV) into Vero cells and swine macrophages is mediated by s aturable binding sites located on the plasma membrane. The ASFV protei n p12 has been implicated in virus attachment to the host cell, but th e cellular component responsible for the interaction with the virus is largely unknown. We have studied the binding of recombinant p12 and A SFV to different cell lines. Permissive cells were able to bind p12 in saturable and nonsaturable interactions, as reported for ASFV. Experi ments of binding recombinant p12 have been used for the initial charac terization of the specific receptors on Vero cells. The treatment of c ell surfaces with different enzymes and lectins resulted in the inhibi tion of the p12 binding activity by several proteases, but not by glyc osidases or lipase, suggesting that the receptor is composed of protei n, with no carbohydrates or lipids involved in the virus attachment to the cellular membrane. The recovery of receptor activity after pronas e treatment was completed in 6 h in culture medium containing tunicamy cin, and could not be restored in the presence of cycloheximide, confi rming that synthesis of new proteins, but not glycosylation, was requi red for the recovery of the receptor activity. These data support the idea that membrane protein(s) on the surface of permissive cells act a s receptors for ASFV and that this specific interaction is, at least, one necessary step in a productive virus infection. (C) 1997 Elsevier Science B.V.