title: Retroviral vectors for high-level transgene expression in T lymphocytes.
abstract: Efficient expression of genes transferred by retroviral vectors is a prerequisite for gene therapy, especially when the biological effect depends on the amount of transgene product. High-level gene expression is desirable for several gene therapy approaches involving T lymphocytes. We evaluated standard retroviral vectors with cis-regulatory control elements of the Moloney murine leukemia virus (Mo-MLV) with or without the human T cell-specific CD2 enhancer. For comparison, vectors containing the long terminal repeat (LTR) of myeloproliferative sarcoma virus (MPSV) and an improved 5' untranslated region were used (MP71 vectors), with or without the woodchuck hepatitis virus posttranscriptional regulatory element (PRE). All vectors expressed the enhanced green fluorescent protein (GFP) to measure transgene expression. In mouse T cells MP71 vectors with and without the PRE yielded an up to 10-fold higher expression level compared with the Mo-MLV-based vectors currently used for gene transfer into T lymphocytes. A high multiplicity of infection (MOI) of standard Mo-MLV vectors could not reach expression levels obtained with a low MOI of MP71 vector. Ex vivo-transduced mouse T lymphocytes maintained the vector-dependent differences in level of transgene expression in Rag-1-deficient mice when adoptively transferred. In four human T cell lines and human primary T lymphocytes MP71 vectors yielded an up to 75-fold higher GFP expression level in comparison with the standard Mo-MLV vector. In contrast to mouse T cells, the integration of the PRE into MP71 vectors induced in human T cells a further significant increase in transgene expression level. Southern blot analysis of CEM T cells revealed that the superior performance of MP71 vectors was not due to a higher rate of viral integration. In summary, MP71 vectors are useful tools for stable, high-level gene expression in T lymphocytes, for example, in the expression of T cell receptor genes.
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Rossle-Strasse 10, 13092 Berlin, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Engels
authors.forename: Hakan
authors.initials: H
authors.lastname: Cam
authors.forename: Thomas
authors.initials: T
authors.lastname: Schüler
authors.forename: Stefano
authors.initials: S
authors.lastname: Indraccolo
authors.forename: Monika
authors.initials: M
authors.lastname: Gladow
authors.forename: Christopher
authors.initials: C
authors.lastname: Baum
authors.forename: Thomas
authors.initials: T
authors.lastname: Blankenstein
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Uckert
mesh_terms: D016475:3T3 Cells; D000818:Animals; D018801:CD2 Antigens / Q000235:genetics; D002460:Cell Line; D002470:Cell Survival; D002478:Cells, Cultured; D004742:Enhancer Elements, Genetic / Q000235:genetics; D015870:Gene Expression; D015316:Genetic Therapy; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics; D051379:Mice; D008979:Moloney murine leukemia virus / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D012190:Retroviridae / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013601:T-Lymphocytes / Q000276:immunology*; D014161:Transduction, Genetic; D019076:Transgenes
chemical_list: D018801:CD2 Antigens; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins