Fig 2.

Antibody responses to BV injection. (A) Anti-BV total IgG titers. (B) Anti-BV IgG1 and IgG2a titers. (C) BV-specific neutralizing antibody (NAb) titers. (D) Transducing titer of Bac-CE in the presence of mouse serum (20× dilution). (E) Effects of gp64-specific antibody on Bac-CE-mediated expression. BALB/c mice (n = 7) were injected i.m. with Bac-luc/w (3 × 10⁹ PFU/mouse) twice, at days 0 and 14, and sera were collected at different time points for analyses. For NAb titer determination, serum samples taken at days 0, 14, and 28 were diluted and incubated with Bac-CE. HeLa cells were transduced with the neutralized Bac-CE, followed by total fluorescence measurement and calculation of NAb titers. For transducing titer measurement, Bac-CE was incubated with diluted sera (20× dilution), followed by determination of transducing titers. To evaluate the effect of anti-gp64 antibody on transduction, serum samples taken at day 28 were diluted 100-fold and mixed with increasing amounts of purified gp64 and Bac-CE. HeLa cells were transduced with the neutralized Bac-CE, and the relative total fluorescence was measured by flow cytometry. Statistical comparisons were performed by one-way ANOVA.