I have questions about a particular paper: Oncolytic Poxvirus Armed with Fas Ligand Leads to Induction of Cellular Fas Receptor and Selective Viral Replication in FasR Negative Cancer The authors explain that they're using an oncolytic virus to deliver membrane-bound Fas ligand to cells in a non-specific manner. Their hypothesis is that apoptosis will be induced in normal cells which are FasR+, thereby aborting viral replication, whereas in cancer cells that have knocked out FasR, the virus will replicate fully and lyse the cell. I'm confused as to how inducing apoptosis in this way will lead to abortive replication in normal cells. If FasL is membrane-bound, won't the virus-infected cell expressing it induce apoptosis in an adjacent, normal cell? That doesn't really seem efficacious. Am I incorrect in assuming that somewhere along the line, there will be a normal cell that allows for productive replication of the virus?