Fig. 3.

FFV Bet is undetectable in purified FFV particle preparations. FFV particles enriched from supernatants of FFV-infected CRFK cells by sedimentation through a sucrose cushion were digested with subtilisin for different time points as indicated below the blot and analyzed by immunoblotting. In parallel, antigen from FFV-infected CRFK cells and molecular mass markers were applied (lanes 1 and 2). The blot in A was reacted with a serum against FFV Bet, the blot in B was probed with an Elp antiserum. The positions of FFV Bet, the Env leader protein gp16^Elp, and the Env signal peptide p9^Env (26) are indicated at right, those of marker proteins are given at left.