FIG. 3.

(A) Growth characteristics of CSFV BICv, CSICv, and chimeric viruses 138.8v, 312.1v, and 319.1v in swine macrophage cell cultures. Primary swine macrophage cell cultures were infected (MOI = 0.1) with CSFV BICv, CSICv, 138.8v, 319.1v, 312.1v, 337.14v, 343.8v, or 137.1v. At times postinfection, samples were collected and titrated for virus yield. Data are means and standard errors from three independent experiments. (B) Plaque formation of CSFV BICv, CSICv, and chimeric viruses on SK6 cell cultures. Cell cultures were infected with 50 to 100 TCID₅₀, overlaid with 0.5% agarose, and incubated at 37°C for 3 days. Plates were fixed with 50% (vol/vol) ethanol-acetone and stained by immunohistochemistry as described in Materials and Methods.