title: Thymidine kinase (TK) gene-transduced human lymphocytes can be highly purified, remain fully functional, and are killed efficiently with ganciclovir.
abstract: A graft-versus-leukemia (GVL) effect has been considered a major factor responsible for cures in patients with hematologic malignancies undergoing allogeneic bone marrow transplantation; however, associated graft-versus-host disease (GVHD) results in significant morbidity and mortality. T-cell depletion reduces the incidence and severity of GVHD but eliminates, at least partially, the GVL effect. Reinfusion of donor T lymphocytes at relapse posttransplantation can induce a potent antitumor response, but GVHD still occurs in the majority of patients. Prior transduction of T lymphocytes with the suicide gene, the viral thymidine kinase (TK), permits specific cell kill on administration of ganciclovir (GCV). Therefore, infusion of TK-transduced T lymphocytes may induce GVL effect and allow for their subsequent selective elimination in case GVHD develops. To evaluate the efficacy and feasibility of this promising approach, anti-CD3-stimulated primary human lymphocytes cultured in interleukin-2 were TK-transduced by a retroviral vector carrying both TK and neomycin-resistance genes. After selection in G418, more than 90% of the cells contained the TK gene as shown by a semiquantitative polymerase chain reaction. In addition, 1 to 5 days of GCV exposure, at clinically achievable concentrations of 20 to 50 micromol/L, induced > or = 90% killing of G418-selected cells without affecting nontransduced cells. Correlation of the extent of T-cell kill and the proportion of TK-gene-transduced cells is consistent with the absence of a bystander effect. Transduced cells were CD3+ and either CD8+ or CD4+ and retained functional properties of untransduced cells. In vivo administration of GCV prevented tumor development after subcutaneous injection of TK-transduced murine myeloma cells (MOPC-11), whereas such an effect was not observed on injection of untransduced cells into the opposite flank. Our studies provide critical information that (1) adequate numbers of TK-transduced lymphocytes can be selected efficiently with > or = 90% purity, (2) selected cells remain functional, (3) 24 hours of exposure to GCV at clinically achievable concentration effects > or = 90% killing of selected cells, and (4) GCV is effective in vivo in killing TK-transduced cells. Based on these data, a clinical study has been initiated in patients with multiple myeloma with persistent or relapsing disease after T-cell-depleted allogeneic transplants.
authors.affiliation: University of Arkansas for Medical Sciences, Little Rock 72205, USA.
authors.forename: N C
authors.initials: NC
authors.lastname: Munshi
authors.forename: R
authors.initials: R
authors.lastname: Govindarajan
authors.forename: R
authors.initials: R
authors.lastname: Drake
authors.forename: L M
authors.initials: LM
authors.lastname: Ding
authors.forename: R
authors.initials: R
authors.lastname: Iyer
authors.forename: R
authors.initials: R
authors.lastname: Saylors
authors.forename: J
authors.initials: J
authors.lastname: Kornbluth
authors.forename: S
authors.initials: S
authors.lastname: Marcus
authors.forename: Y
authors.initials: Y
authors.lastname: Chiang
authors.forename: D
authors.initials: D
authors.lastname: Ennist
authors.forename: L
authors.initials: L
authors.lastname: Kwak
authors.forename: C
authors.initials: C
authors.lastname: Reynolds
authors.forename: G
authors.initials: G
authors.lastname: Tricot
authors.forename: B
authors.initials: B
authors.lastname: Barlogie
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002469:Cell Separation; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D015774:Ganciclovir / Q000494:pharmacology*; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D016219:Immunotherapy, Adoptive; D008214:Lymphocytes / Q000187:drug effects* / Q000201:enzymology; D051379:Mice; D008807:Mice, Inbred BALB C; D008979:Moloney murine leukemia virus / Q000235:genetics; D009101:Multiple Myeloma / Q000473:pathology; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000201:enzymology; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors; D018139:Simplexvirus / Q000201:enzymology / Q000235:genetics; D013937:Thymidine Kinase / Q000037:antagonists & inhibitors / Q000235:genetics*; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D011994:Recombinant Proteins; D013937:Thymidine Kinase; D015774:Ganciclovir