FIG. 2.

Effect of incubation of PAM with heparin before infection. PAM were incubated for 1 h at 37°C with heparin, washed extensively, and incubated with PRRSV (solid bars), PrV (shaded bars), and PrV gC⁻ (open bars). The cells were washed after 2 h of incubation to remove unbound virus, and the cells were fixed after 10 h. The data represent the means ± standard deviations (error bars) of triplicate assays. No significant differences were observed in comparison to the control (no heparin added).