Novel DAF-displaying Ads minimize Ad-mediated complement activation in vitro. (A) Activation of complement alternative pathway mediated by control and DAF-displaying Ads was performed. Residual complement activity was normalized to NHS incubated with media (no_virus control). Data from a representative experiment are shown. The error bars represent ± SD. Statistical analysis was completed using 1-way analysis of variance with a Student-Newman-Keuls post hoc test. ## indicates statistically different values from Ad5-IX-dGFP and Ad5-GFP, P < .001. (B) Complement activation mediated by control and DAF-displaying Ads was determined by C3a-desArg–specific enzyme-linked immunoabsorbent assay (ELISA). Negative control was incubated with NHS and with PBS before ELISA. Data from a representative experiment are shown. The error bars represent ± SD. Statistical analysis was completed using 1-way analysis of variance with a Student-Newman-Keuls post hoc test. Complement activation by DAF-displaying Ads was compared with corresponding controls. Values statistically different from negative control, **P < .001; statistically different values from Ad5-IX-dGFP and Ad5-GFP, ##P < .001, respectively. Note that Ad5-GFP-IX-dDAF_REO virus did not significantly activate complement. AP50 indicates alternative pathway 50.