FIG. 8.

K1L's ability to antagonize hIFN-β in Huh7 cells correlates with its host range function in HeLa cells. Huh7 cells were left untreated (−) or were treated (+) with 200 U/ml of hIFN-β for 24 h and infected with a panel of K1L mutant VACV strains at an MOI of 5. Viral yields at 24 hpi were determined by plaque assay. The mutants were all derived from vK1L⁻C7L⁻ and encode a K1 protein with specific amino acid substitutions at its ankyrin repeats (19). The previously reported replication capacities of the mutants in HeLa cells are summarized below the name of the mutant virus. +, WT level of replication; −, no viral replication; ±, partial defect in viral replication.