We describe a method to genetically modify primary human T cells with a transgene using the non-viral piggyBac transposon system. T cells modified to using the piggyBac transposon system exhibit stable transgene expression.
The piggyBac transposon system is naturally active, originally derived from the cabbage looper moth1,2. This non-viral system is plasmid based, most commonly utilizing two plasmids with one expressing the piggyBac transposase enzyme and a transposon plasmid harboring the gene(s) of interest between inverted repeat elements which are required for gene transfer activity. PiggyBac mediates gene transfer through a “cut and paste” mechanism whereby the transposase integrates the transposon segment into the genome of the target cell(s) of interest. PiggyBac has demonstrated efficient gene delivery activity in a wide variety of insect1,2, mammalian3-5, and human cells6 including primary human T cells7,8. Recently, a hyperactive piggyBac transposase was generated improving gene transfer efficiency9,10.
Human T lymphocytes are of clinical interest for adoptive immunotherapy of cancer11. Of note, the first clinical trial involving transposon modification of human T cells using the Sleeping beauty transposon system has been approved12. We have previously evaluated the utility of piggyBac as a non-viral methodology for genetic modification of human T cells. We found piggyBac to be efficient in genetic modification of human T cells with a reporter gene and a non-immunogenic inducible suicide gene7. Analysis of genomic integration sites revealed a lack of preference for integration into or near known proto-oncogenes13. We used piggyBac to gene-modify cytotoxic T lymphocytes to carry a chimeric antigen receptor directed against the tumor antigen HER2, and found that gene-modified T cells mediated targeted killing of HER2-positive tumor cells in vitro and in vivo in an orthotopic mouse model14. We have also used piggyBac to generate human T cells resistant to rapamycin, which should be useful in cancer therapies where rapamycin is utilized15.
Herein, we describe a method for using piggyBac to genetically modify primary human T cells. This includes isolation of peripheral blood mononuclear cells (PBMCs) from human blood followed by culture, gene modification, and activation of T cells. For the purpose of this report, T cells were modified with a reporter gene (eGFP) for analysis and quantification of gene expression by flow cytometry.
PiggyBac can be used to modify human T cells with a variety of genes of interest. Although we have used piggyBac to direct T cells to tumor antigens14, we have also used piggyBac to add an inducible safety switch in order to eliminate gene modified cells if needed7. The large cargo capacity of piggyBac has also enabled gene transfer of a large rapamycin resistant mTOR molecule (15 kb)15. Therefore, we present a non-viral methodology for stable gene-modification of primary human T cells for a wide variety of purposes.
The method described herein enables stable transgene modification of primary human T lymphocytes. We have previously tested the use of the piggyBac transposon system to modify T cells to express a reporter gene (for more than 4 weeks), a non-immunogenic suicide gene, a chimeric antigen receptor for adoptive immunotherapy (for more than 100 days), and to engineer resistance to immunosuppressive medications7,13-15. Non-viral modification of T cells for adoptive immunotherapy and other applications shoul…
The authors have nothing to disclose.
SS is supported in part by the HHMI Med into Grad Training Grant through the TBMM Program. MHW is supported in part by a career development award from the Department of Veterans Affairs and the generous support of Dr. and Mrs. Harold M. Selzman. This work was also supported in part by NIH lymphoma SPORE grant P50CA126752 and NIH R01 DK093660.
Name of the reagent | Company | Catalogue number | Comments (optional) |
Lympholyte | Cedarlane | CL5015 | |
Advanced RPMI 1,640 | LifeTechnologies | 12633020 | |
Hyclone Fetal Bovine Serum | Fisher Scientific | SH3008803 | |
GlutaMAX-I Supplement | LifeTechnologies | 35050-061 | |
Human IL-15 Recombinant Protein | eBioscience | 14-8159 | |
EndoFree Plasmid Maxi Kit | Qiagen | 12362 | |
Amaxa Nucleofector | Lonza | AAD-1001S | |
Human T Cell Nucleofector Kit | Lonza | VPA-1002 | |
CD8-APC | Southern Biotech | 9536-11 | |
Anti-Human CD3 | eBioscience | 16-0037-81 | |
Anti-Human CD28 | BD Pharmingen | 555725 | |
24 Well Tissue Culture Treated Plate | BD Falcon | 353047 | |
24 Well Non Tissue Culture Treated Plate | BD Falcon | 351147 | |
Complete T cell media composition 1x Advanced RPMI 1,640 5% Heat Inactivated Fetal Bovine Serum 2 mM GlutamaxIM-I |