Fig. 1: Several mechanisms can be employed to enrich gammaretroviral and lentiviral vector-modified cells in vitro or in vivo.
From: Retroviral gene therapy in Germany with a view on previous experience and future perspectives
For example, antibodies can be used to purify modified cells transduced with vectors designed to express truncated forms of CD34 (tCD34) or the low-affinity nerve growth receptor (ΔLNGFR). Cells can be engineered to express suicide genes such as the Herpes simplex virus thymidine kinase (scHSVtk) or variants (e.g., TK007) to allow elimination of cells in the case of adverse events. Cells can also be modified to express the multidrug resistance protein MDR-1 or the methylguanine methyltransferase P140K mutant (MGMTP140K) to endow improved resistance against medications such as chemotherapy so that only the modified cells (cells with the red rectangle) persist upon drug treatment. Knockout of receptors like CCR5 and CXCR4 can protect cells from HIV-1 infection. Furthermore, modification of cells to express small membrane-bound C peptides such as T20 and C46 can also prevent HIV-1 infection of modified cells. Retroviral particles were created with Biorender.com.
