Figure 1.

KM100 displays limited oncolytic activity in IFN-responsive NOP32 cells and HER-2/neu primary tumor explants cells. (a) HER-2/neu tumor explant cells and the neu^OT-I/OT-II transgenic cell line NOP32 were infected at varying multiplicities of infection (MOIs) for 3 days with wild-type Herpes simplex virus strain KOS, the infected cell protein 0-null HSV n212, or the oncolytic KM100, and cytopathic effects were visualized by Giemsa staining. (b) Parallel cultures of HER-2/neu and NOP32 cells were infected at a MOI of 2.5 and harvested for quantification of total infectious virus by plaque assay. Data are expressed as means ± SD. Limit of detection of plaque assay, log₁₀ = 2.3 (c) Interferon (IFN) responsiveness assays were performed as in Materials and Methods. Shown are the average, log-transformed green fluorescent protein (GFP) fluorescence ratios of tumor cell cultures pretreated with regular growth medium (-IFN) or with varying doses of IFN (+IFN) from three experiments performed in triplicate. Low ratio values denote cellular IFN unresponsiveness. Data are representative of three independent experiments.