Browsing by Subject "Retrovirus"

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    Screening Clinical Cell Products for Replication Competent Retrovirus: The National Gene Vector Biorepository Experience
    (Elsevier, 2018-09-21) Cornetta, Kenneth; Duffy, Lisa; Feldman, Steven A.; Mackall, Crystal L.; Davila, Marco L.; Curran, Kevin J.; Junghans, Richard P.; Tang, Jean Yuh; Kochenderfer, James N.; O'Cearbhaill, Roisin; Archer, Gary; Kiem, Hans-Peter; Shah, Nirali N.; Delbrook, Cindy; Kaplan, Rosie; Brentjens, Renier J.; Rivière, Isabelle; Sadelain, Michel; Rosenberg, Steven A.; Medical and Molecular Genetics, School of Medicine
    Replication-competent retrovirus (RCR) is a safety concern for individuals treated with retroviral gene therapy. RCR detection assays are used to detect RCR in manufactured vector, transduced cell products infused into research subjects, and in the research subjects after treatment. In this study, we reviewed 286 control (n = 4) and transduced cell products (n = 282) screened for RCR in the National Gene Vector Biorepository. The transduced cell samples were submitted from 14 clinical trials. All vector products were previously shown to be negative for RCR prior to use in cell transduction. After transduction, all 282 transduced cell products were negative for RCR. In addition, 241 of the clinical trial participants were also screened for RCR by analyzing peripheral blood at least 1 month after infusion, all of which were also negative for evidence of RCR infection. The majority of vector products used in the clinical trials were generated in the PG13 packaging cell line. The findings suggest that screening of the retroviral vector product generated in PG13 cell line may be sufficient and that further screening of transduced cells does not provide added value.
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    The common murine retroviral integration site activating Hhex marks a distal regulatory enhancer co-opted in human early T-cell precursor leukemia
    (American Society for Biochemistry and Molecular Biology, 2025) Hardwick, Joyce; Rodriguez-Hernaez, Javier; Gambi, Giovanni; Venters, Bryan J.; Guo, Yan; Li, Liqi; Love, Paul E.; Copeland, Neal G.; Jenkins, Nancy A.; Papaioannou, Dimitrios; Aifantis, Iannis; Tsirigos, Aristotelis; Ivan, Mircea; Davé, Utpal P.; Medicine, School of Medicine
    The Hhex gene encodes a transcription factor that is important for both embryonic and post-natal development, especially of hematopoietic tissues. Hhex is one of the most common sites of retroviral integration in mouse models. We found the most common integrations in AKXD (recombinant inbred strains) T-ALLs occur 57-61kb 3′ of Hhex and activate Hhex gene expression. The genomic region of murine leukemia virus (MLV) integrations has features of a developmental stage-specific cis regulatory element (CRE), as evidenced by ATAC-seq in murine progenitor cells and high H3K27 acetylation at the syntenic CRE in human hematopoietic cell lines. With ChIP-exonuclease, we describe occupancy of LIM domain binding protein 1 (LDB1), the constitutive partner of the LIM Only-2 (LMO2), GATA1, and TAL1 transcription factors at GATA sites and at a composite GATA-E box within the CRE. With virtual 4C analysis, we observed looping between this +65kb CRE and the proximal intron one enhancer of HHEX in primary human ETP-ALLs and in normal progenitor cells. Our results show that retroviral integrations at intergenic sites can mark and take advantage of CREs. Specifically, in the case of HHEX activation, this newly described +65kb CRE is co-opted in the pathogenesis of ETP-ALL by the LMO2/LDB1 complex.