Efficient gene delivery into Epstein-Barr virus (EBV)-transformed human B cells mediated by replication-defective herpes simplex virus-1 (HSV-1): A gene therapy model for EBV-related B cell malignancy

Subgroups of the B cell malignancies are known to be associated with Epstei n-Barr virus (EBV) infection, especially in immunocompromised patients. The se are fatal and refractory to conventional antineoplastic therapy. B cells are usually post-mitotic cells and even mitogen activated or transformed B cells have shown relative resistance against viral mediated gene transfer. To address this issue, we employed a replication-defective herpes simplex virus-1 (HSV-1) to mediate gene transfer into EBV-transformed B cells. The virus expresses the herpes simplex virus thymidine kinase (HSV-TK) and the E. coil lacZ reporter genes and is designated T0Z.1. We used the lymphoblas toid cell line SWEIG as a model for human EBV-related B cell malignancy. Th is cell line was established by in vitro EBV infection of primary human per ipheral blood mononuclear cells. When SWEIG cells were infected with T0Z.1, X-gal staining revealed lacZ expression in more than 20% cells even at mul tiplicity of infection (MOI) as low as 1 and the expression persisted for a t least one week. Ganciclovir (GCV) administration after T0Z.1 infection ef fectively decreased the number of the infected tumor cells in a dose-respon sive manner. Viral toxicity aas analyzed by cell proliferation assay (MTS a ssay) and found to be Little even at 10 MOI infection. Three MOI of the vir us yielded maximum antineoplastic effect and more than 50% tumor cells were killed by HSV-TK/GCV. These results suggest the potential utility of repli cation-defective HSV-1 for the treatment of EBV-related B cell malignancies , (C) 1998 Academic Press.