[HTML][HTML] Generation of genetically engineered precursor T-cells from human umbilical cord blood using an optimized alpharetroviral vector platform

J Hübner, SS Hoseini, JD Suerth, D Hoffmann… - Molecular Therapy, 2016 - cell.com
J Hübner, SS Hoseini, JD Suerth, D Hoffmann, M Maluski, J Herbst, H Maul, A Ghosh
Molecular Therapy, 2016cell.com
Retroviral engineering of hematopoietic stem cell-derived precursor T-cells (preTs) opens
the possibility of targeted T-cell transfer across human leukocyte antigen (HLA)-barriers.
Alpharetroviral vectors exhibit a more neutral integration pattern thereby reducing the risk of
insertional mutagenesis. Cord blood-derived CD34+ cells were transduced and
differentiated into preTs in vitro. Two promoters, elongation-factor-1-short-form, and a
myeloproliferative sarcoma virus variant in combination with two commonly used envelopes …
Retroviral engineering of hematopoietic stem cell-derived precursor T-cells (preTs) opens the possibility of targeted T-cell transfer across human leukocyte antigen (HLA)-barriers. Alpharetroviral vectors exhibit a more neutral integration pattern thereby reducing the risk of insertional mutagenesis. Cord blood-derived CD34+ cells were transduced and differentiated into preTs in vitro. Two promoters, elongation-factor-1-short-form, and a myeloproliferative sarcoma virus variant in combination with two commonly used envelopes were comparatively assessed choosing enhanced green fluorescent protein or a third-generation chimeric antigen receptor (CAR) against CD123 as gene of interest. Furthermore, the inducible suicide gene iCaspase 9 has been validated. Combining the sarcoma virus-derived promoter with a modified feline endogenous retrovirus envelope glycoprotein yielded in superior transgene expression and transduction rates. Fresh and previously frozen CD34+ cells showed similar transduction and expansion rates. Transgene-positive cells did neither show proliferative impairment nor alteration in their lymphoid differentiation profile. The sarcoma virus-derived promoter only could express sufficient levels of iCaspase 9 to mediate dimerizer-induced apoptosis. Finally, the CD123 CAR was efficiently expressed in CD34+ cells and proved to be functional when expressed on differentiated T-cells. Therefore, the transduction of CD34+ cells with alpharetroviral vectors represents a feasible and potentially safer approach for stem cell-based immunotherapies for cancer.
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