HIV-1 sequences in lentiviral vector genomes can be substantially reduced without compromising transduction efficiency

Effects of an indole derivative on cell proliferation, transfection, and alternative splicing in production of lentiviral vectors by transient co-transfection

Lentiviral vectors derived from human immunodeficiency virus type I are widely used to deliver functional gene copies to mammalian cells for research and gene therapies. Post-transcriptional splicing of lentiviral vector transgene in transduced host and transfected producer cells presents barriers to widespread application of lentiviral vector-based therapies. The present study examined effects of indole derivative compound IDC16 on splicing of lentiviral vector transcripts in producer cells and corresponding yield of infectious lentiviral vectors. Indole IDC16 was shown previously to modify alternative splicing in human immunodeficiency virus type I. Human embryonic kidney 293T cells were transiently transfected by 3rd generation backbone and packaging plasmids using polyethyleneimine. Reverse transcription-quantitative polymerase chain reaction of the fraction of unspliced genomes in human embryonic kidney 293T cells increased up to 31% upon the indole's treatment at 2.5 uM. Corresponding yield of infectious lentiviral vectors decreased up to 4.5-fold in a cell transduction assay. Adjusting timing and duration of IDC16 treatment indicated that the indole's disruption of early stages of transfection and cell cycle had a greater effect on exponential time course of lentiviral vector production than its reduction of post-transcriptional splicing. Decrease in transfected human embryonic kidney 293T proliferation by IDC16 became significant at 10 uM. These findings indicated contributions by early-stage transfection, cell proliferation, and post-transcriptional splicing in transient transfection of human embryonic kidney 293T cells for lentiviral vector production.

CAR-T cell potency: from structural elements to vector backbone components

Chimeric antigen receptor (CAR) T cell therapy, in which a patient’s own T lymphocytes are engineered to recognize and kill cancer cells, has achieved remarkable success in some hematological malignancies in preclinical and clinical trials, resulting in six FDA-approved CAR-T products currently available in the market. Once equipped with a CAR construct, T cells act as living drugs and recognize and eliminate the target tumor cells in an MHC-independent manner. In this review, we first described all structural modular of CAR in detail, focusing on more recent findings. We then pointed out behind-the-scene elements contributing to CAR expression and reviewed how CAR expression can be drastically affected by the elements embedded in the viral vector backbone.