FIG. 6.

Analysis of PFV SU cysteine point mutants. (A) Schematic outline of the PFV Env domain organization and the PFV Env SU immunoadhesin AD3.1 with annotated positions of the individual cysteine residues. For abbreviations, see legend to Fig. 2. (B) Western blot analysis of 293T supernatant (50 μl) containing different PFV Env immunoadhesins or purified immunoadhesins (marked by asterisks) and controls, as indicated, using polyclonal anti-mouse IgG-Fcγ or monoclonal anti-PFV SU-specific antibodies. The identities of the individual proteins are given on the right. (C) Mean fluorescences and corresponding standard deviations (n = 1 to 3) of different immunoadhesins and controls on HT1080 target cells. Due to the poor secretion, some mutants could be analyzed for binding activity only once (ΔC6, ΔC11) or twice (ΔC5, ΔC8, ΔC16). Staining was done using 100 ng immunoadhesin or control in a volume of 435 μl.