Growth characteristics of ASFV isolates E70, ΔUK, and UK-R in swine macrophage cell cultures. Porcine macrophage cell cultures were infected (MOI, 1) with E70, ΔUK, and UK-R viruses. At indicated times postinfection duplicate samples were collected and titrated for extracellular (A) and intracellular (B) virus yields. Data are the means and standard errors of results from two independent experiments.