Reovirus and human cancer cell lines. (A) Effect of reovirus on human cancer cell lines. Monocytic (U937, left panel) and myeloma (RPMI 8226, right panel) cells were infected with reovirus at an MOI of 40 PFU/cell. Cells were harvested at 0, 1, 2, 3, 4, and 7 days after infection, and intact cancer cells were enumerated with propidium iodide using flow cytometry. The values depicted are the means and standard deviations of 4 replicates. ♦ indicates no virus; ▪, live virus. (B) Reovirus protein synthesis in cancer cell lines. Human monocytic (U937, left panel) and myeloma (RPMI 8226, right panel) cells were infected with reovirus at a MOI of 40 PFUs and pulse labeled with [³⁵S]-methionine for various time points as indicated in the figures. Following labeling, the cells were harvested and lysed, and cellular proteins were subjected to SDS-PAGE. Reovirus proteins (λ, μ, and σ) are shown in lane 1. Reovirus infection and protein synthesis were found in both cell lines.