Figure 7.

SV5 spreads farther than T3wt due to its reduced binding to cells

(A) Diffusion of T3wt and SV5 in 0.5% agar (same agar concentration that was used for plaque assays) in the absence of cells (n = 7). Each point represents an independent experiment. Colored lines were calculated using a local polynomial regression fitting formula (LOESS). (B) Consecutive-binding experiment showing the infectivity of unbound T3wt and SV5 virus particles to L929 cells over 10 consecutive binding opportunities (n = 4). Percentage of infected cells was evaluated by flow cytometry and the percentage of cells infected by T3wt was normalized to 1. p values were calculated with a Student’s t test. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001; ns, not significant. (C) Plaque assays to evaluate plaque size of T3wt and SV5 in the presence of different concentrations of neuraminidase (0, 0.6, 1.2, 2.4, and 9.6 U/mL) to reduce virus binding (n = 3–4). T3wt and SV5 without neuraminidase were normalized to 1 in each of the plates. p values were calculated with a one-sample t test with multiple comparison adjustments. ∗p < 0.05, ∗∗p < 0.01; ns, not significant, relative to T3wt or SV5 without neuraminidase treatment.