title: Non-integrating lentiviral vectors for specific killing of Epstein-Barr virus nuclear antigen 1-positive B cell lymphoma cells.
abstract: BACKGROUND
  Epstein-Barr virus (EBV) causes a range of life-threatening B-lymphocyte malignancies but, despite the use of various strategies, treatment remains problematic.
  
  
  METHODS
  In the present study, we developed a non-integrating lentiviral vector (NILV) that mediates specific killing of EBV nuclear antigen 1 (EBNA1)-expressing cells with minimal toxicity to EBNA1-negative cells. The EBV family of repeats (FR) was cloned intok the NILV genome upstream of various transgenes.
  
  
  RESULTS
  The presence of the FR in the NILV genome induced transcriptional up-regulation and prolonged the expression of a transgene specifically in EBNA1-positive B cells. Transgene expression from an FR-containing NILV was also prolonged in EBV-transformed cells compared to an FR-negative NILV. We found that the delivery of an FR-containing NILV encoding herpes simplex virus 1 thymidine kinase (TK) lead to the killing of more than 99% of EBNA1-positive B cells with minimal toxicity to EBNA1-negative cells in the presence of gancyclovir. EBNA1-positive cells were not killed by an FR-negative vector containing the TK gene. An FR-TK-containing NILV also specifically killed EBNA1-containing cells in a mixed population of EBNA1-positive and EBNA1-negative cells, thus confirming that NILV-FR-TK-mediated killing is specific for EBNA1-expressing cells.
  
  
  CONCLUSIONS
  Transgene expression from our NILVs is both EBNA1-specific and dependent upon the presence of the FR. The results obtained in the present study indicate that NILVs have potential use in the treatment of EBV-associated B cell malignancies.
authors.affiliation: Division of Rheumatic and Autoimmune Diseases, Department of Medicine, Institute of Human Genetics, Masonic Cancer Center, University of Minnesota Medical School, Minneapolis, MN, USA.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Flynn
authors.forename: Jeana
authors.initials: J
authors.lastname: Zacharias
authors.forename: Xianzheng
authors.initials: X
authors.lastname: Zhou
authors.forename: Mark L
authors.initials: ML
authors.lastname: Cannon
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Philpott
mesh_terms: D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D019309:Epstein-Barr Virus Nuclear Antigens / Q000378:metabolism*; D015774:Ganciclovir / Q000494:pharmacology; D005786:Gene Expression Regulation; D023061:Gene Order; D018014:Gene Transfer Techniques; D041722:Genes, Transgenic, Suicide; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000235:genetics*; D057809:HEK293 Cells; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D016393:Lymphoma, B-Cell / Q000628:therapy* / Q000821:virology; D013937:Thymidine Kinase / Q000235:genetics; D014158:Transcription, Genetic; D014161:Transduction, Genetic; D015854:Up-Regulation / Q000235:genetics
chemical_list: D019309:Epstein-Barr Virus Nuclear Antigens; D013937:Thymidine Kinase; C417029:EBV-encoded nuclear antigen 1; D015774:Ganciclovir