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.

Day 0
1. Isolation of PBMCs from Human Blood
<ol>
	<li>Collect 20 ml of fresh human blood using venipuncture into Na-heparin vacutainer tubes.</li>
	<li>Mix blood and Advanced RPMI 1,640 in 1:1 (v/v) ratio.</li>
	<li>Add 20 ml lymphoprep medium to a 50 ml centrifuge tube (25 &deg;C). Slowly layer 25-30 ml of blood-RPMI 1,640 mix on top of the lymphoprep.</li>
	<li>Centrifuge at 400 x g for 40 min without brakes.</li>
	<li>Collect both distinct and fuzzy layers using a disposable pipette into 10 ml of 1x PBS (25 &deg;C) and bring the volume up to 50 ml with 1x PBS.</li>
	<li>Centrifuge at 450 x g for 10 min.</li>
	<li>Aspirate the supernatant completely and add 20 ml of Advanced RPMI 1,640.</li>
	<li>Centrifuge at 400 x g for 5 min.</li>
	<li>Aspirate the supernatant. Add 10 ml of complete T cell media supplemented with 5 ng/ml rhIL-15 prewarmed at 37 &deg;C.</li>
	<li>Count the number of cells and plate in a 24 well tissue culture coated plate at 2 x 106 cells/well in complete T cell media supplemented with 5 ng/ml rhIL-15 Add sterile water to surrounding wells. Incubate overnight in a humidified incubator at 37 &deg;C, 5% CO2.</li>
</ol>
Day 1
2. Coating Plates with anti-CD28 and anti-CD3 Antibody for Stimulating T cells
<ol>
	<li>Dilute anti-CD28 and anti-CD3 antibodies in sterile water at a concentration of 1 &mu;g/ml each.</li>
	<li>Add 500 &mu;l each antibody solution to 5 marked wells of a non-coated tissue culture 24 well plate.</li>
	<li>Add sterile water to rest of the wells. Wrap the plate in shrink wrap and place in a 4 &deg;C refrigerator.</li>
</ol>
3. Nucleofection of Unstimulated T Cells
<ol>
	<li>Prewarm T cell media at 37 &deg;C and supplement with 5 ng/ml of rhIL-15. Prepare complete nucleofector solution by adding 500 &mu;l of Nucleofector Supplement 1 to 2.25 ml of Nucleofector solution.</li>
	<li>Aliquot 5 &mu;g each of transposon (Zeo-pT-CMV-eGFP) and transposase (pCMV-piggyBac) in a 1.5 ml microfuge tube. Note: it may be necessary to optimize the transposase and transposon DNA amount for optimal gene delivery and to minimize cellular toxicity. The plasmids can be obtained from the authors by request.</li>
	<li>Harvest PBMCs from the 24 well tissue culture plate into a 50 ml tube. Count the number of cells. Save 2 x 106 cells for use as control during flow cytometry.</li>
	<li>Add 7-10 x 106 cells to a 15 ml tube and centrifuge at 400 x g, 5 min, aspirate supernatant and finger-flick the pellet.</li>
	<li>Add 100 &mu;l of T cell complete nucleofection solution to loosened cell pellet.</li>
	<li>Add the solution-cell mixture to the tube containing the plasmids.</li>
	<li>Add the solution-cell-plasmid mixture to the bottom of the nucleofection cuvette. Be careful not to introduce any bubbles.</li>
	<li>Nucleofect the cells using program U-014 (Unstimulated T cells, human, <a href="http://bio.lonza.com/resources/product-instructions/protocols/" target="_blank">http://bio.lonza.com/resources/product-instructions/protocols/</a>).</li>
	<li>Immediately add 500 &mu;l of prewarmed media with rhIL-15 to the cuvette. Transfer the cells to a well of a 24 well plate with 1.5 ml of prewarmed media with rhIL15.</li>
	<li>Incubate overnight in a humidified incubator at 37 &deg;C, 5% CO2.</li>
</ol>
Day 2
4. Nonspecific Stimulation of T Cells
<ol>
	<li>Harvest cells and determine cell numbers. Set aside 0.5 x 106 cells for flow cytometry to determine the frequency of GFP-positive cells. Use the non-transfected PBMCs as controls.</li>
	<li>Aspirate the CD3/28 antibody solution from the non tissue culture coated plate and rinse each well with T cell media.</li>
	<li>Resuspend the nucleofected cells at 0.5 x 106 cells per ml in complete CTL media supplemented with 5 ng/ml rhIL-15. Add 2.0 ml each of the nucleofected cells in 4 wells of the non tissue culture plate. Add 0.5 x 106 non nucleofected cells to the 5th well.</li>
	<li>Incubate for 3 days in a humidified incubator at 37 &deg;C, 5% CO2.</li>
</ol>
Day 5
<ol>
	<li>Harvest the stimulated T cells from the non-coated tissue culture plate.</li>
	<li>Count and replate the cells in a 24 well coated tissue culture plate at 0.7 x 106 cells/ml in T cell media with 5 ng/ml IL-15.</li>
</ol>
Day 7
7. Analysis of Gene Expression
<ol>
	<li>Harvest cells and stain with anti-human CD8 antibody (could also use anti-CD3 and anti-CD4) and analyze with flow cytometry for %GFP expression.</li>
</ol>
Day 8 (Optional)
8. Expansion of T cells
<ol>
	<li>On day 8 after transfection, T cells can be replated in T-cell media with IL-15 at a density of 0.7 x 106 cells per well for further expansion16.</li>
</ol>

<ol>
	<li>Cary, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transposon+mutagenesis+of+baculoviruses:+analysis+of+Trichoplusia+ni+transposon+IFP2+insertions+within+the+FP-locus+of+nuclear+polyhedrosis+viruses.">Transposon mutagenesis of baculoviruses: analysis of Trichoplusia ni transposon IFP2 insertions within the FP-locus of nuclear polyhedrosis viruses.</a> Virology. 172 (1), 156 (1989).</li><li>Fraser, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assay+for+movement+of+Lepidopteran+transposon+IFP2+in+insect+cells+using+a+baculovirus+genome+as+a+target+DNA.">Assay for movement of Lepidopteran transposon IFP2 in insect cells using a baculovirus genome as a target DNA.</a> Virology. 211 (2), 397 (1995).</li><li>Ding, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+transposition+of+the+piggyBac+(PB)+transposon+in+mammalian+cells+and+mice.">Efficient transposition of the piggyBac (PB) transposon in mammalian cells and mice.</a> Cell. 122 (3), 473 (2005).</li><li>Saridey, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PiggyBac+transposon-based+inducible+gene+expression+in+vivo+after+somatic+cell+gene+transfer.">PiggyBac transposon-based inducible gene expression in vivo after somatic cell gene transfer.</a> Mol. Ther. 17 (12), 2115 (2009).</li><li>Nakanishi, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=piggyBac+transposon-mediated+long-term+gene+expression+in+mice.">piggyBac transposon-mediated long-term gene expression in mice.</a> Mol. Ther. 18 (4), 707 (2010).</li><li>Wilson, M. H., Coates, C. J., George, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PiggyBac+Transposon-mediated+Gene+Transfer+in+Human+Cells.">PiggyBac Transposon-mediated Gene Transfer in Human Cells.</a> Mol. Ther. 15 (1), 139 (2007).</li><li>Nakazawa, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+the+PiggyBac+transposon+system+for+the+sustained+genetic+modification+of+human+T+lymphocytes.">Optimization of the PiggyBac transposon system for the sustained genetic modification of human T lymphocytes.</a> J. Immunother. 32 (8), 826 (2009).</li><li>Raja Manuri, P. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=piggyBac+transposon/transposase+system+to+generate+CD19-specific+T+cells+for+treatment+of+B-lineage+malignancies.">piggyBac transposon/transposase system to generate CD19-specific T cells for treatment of B-lineage malignancies.</a> Hum. Gene Ther. 21 (4), 427 (2010).</li><li>Doherty, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperactive+piggyBac+gene+transfer+in+human+cells+and+in+vivo.">Hyperactive piggyBac gene transfer in human cells and in vivo.</a> Hum. Gene Ther. , (2011).</li><li>Yusa, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+hyperactive+piggyBac+transposase+for+mammalian+applications.">A hyperactive piggyBac transposase for mammalian applications.</a> Proc. Natl. Acad. Sci. U.S.A. 108 (4), 1531 (2011).</li><li>Bonini, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+modification+of+T+cells.">Genetic modification of T cells.</a> Biol. Blood Marrow Transplant. 17, S15-S20 (2011).</li><li>Hackett, P. B., Largaespada, D. A., Cooper, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+transposon+and+transposase+system+for+human+application.">A transposon and transposase system for human application.</a> Mol. Ther. 18 (4), 1531 (2010).</li><li>Galvan, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome-wide+mapping+of+PiggyBac+transposon+integrations+in+primary+human+T+cells.">Genome-wide mapping of PiggyBac transposon integrations in primary human T cells.</a> J. Immunother. 32 (8), 837 (2009).</li><li>Nakazawa, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PiggyBac-Mediated+Cancer+Immunotherapy+Using+EBV-Specific+Cytotoxic+T-Cells+Expressing+HER2-Specific+Chimeric+Antigen+Receptor.">PiggyBac-Mediated Cancer Immunotherapy Using EBV-Specific Cytotoxic T-Cells Expressing HER2-Specific Chimeric Antigen Receptor.</a> Mol. Ther. 19 (12), 2133 (2011).</li><li>Huye, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combining+mTor+Inhibitors+With+Rapamycin-resistant+T+Cells:+A+Two-pronged+Approach+to+Tumor+Elimination.">Combining mTor Inhibitors With Rapamycin-resistant T Cells: A Two-pronged Approach to Tumor Elimination.</a> Mol. Ther. 19 (12), 2239 (2011).</li><li>Vera, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accelerated+production+of+antigen-specific+T+cells+for+preclinical+and+clinical+applications+using+gas-permeable+rapid+expansion+cultureware+(G-Rex).">Accelerated production of antigen-specific T cells for preclinical and clinical applications using gas-permeable rapid expansion cultureware (G-Rex).</a> J. Immunother. 33 (3), 305 (2010).</li><li>Kahlig, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiplexed+transposon-mediated+stable+gene+transfer+in+human+cells.">Multiplexed transposon-mediated stable gene transfer in human cells.</a> Proc. Natl. Acad. Sci. U.S.A. 107 (4), 1343 (2010).</li></ol>

No conflicts of interest declared.

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...

<table border="1">
 <tbody>
 <tr>
 <td>Name of the reagent</td>
 <td>Company</td>
 <td>Catalogue number</td>
 <td>Comments (optional)</td>
 </tr>
 <tr>
 <td>Lympholyte</td>
 <td>Cedarlane</td>
 <td>CL5015</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Advanced RPMI 1,640</td>
 <td>LifeTechnologies</td>
 <td>12633020</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Hyclone Fetal Bovine Serum</td>
 <td>Fisher Scientific</td>
 <td>SH3008803</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>GlutaMAX-I Supplement</td>
 <td>LifeTechnologies</td>
 <td>35050-061</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Human IL-15 Recombinant Protein</td>
 <td>eBioscience</td>
 <td>14-8159</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>EndoFree Plasmid Maxi Kit</td>
 <td>Qiagen</td>
 <td>12362</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Amaxa Nucleofector</td>
 <td>Lonza</td>
 <td>AAD-1001S</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Human T Cell Nucleofector Kit</td>
 <td>Lonza</td>
 <td>VPA-1002</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>CD8-APC</td>
 <td>Southern Biotech</td>
 <td>9536-11</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Anti-Human CD3</td>
 <td>eBioscience</td>
 <td>16-0037-81</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Anti-Human CD28</td>
 <td>BD Pharmingen</td>
 <td>555725</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>24 Well Tissue Culture Treated Plate</td>
 <td>BD Falcon</td>
 <td>353047</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>24 Well Non Tissue Culture Treated Plate</td>
 <td>BD Falcon</td>
 <td>351147</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 <td>Complete T cell media composition 
 1x Advanced RPMI 1,640 
 5% Heat Inactivated Fetal Bovine Serum 
 2 mM GlutamaxIM-I</td>
 </tr>
 </tbody>
</table>

piggybac transposon system modification of primary human t cells

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.

A schematic demonstrating the steps in genetically modifying human T lymphocytes with a reporter gene (eGFP) is shown in Figure 1. These plasmids are available upon request from the authors. A schemtic demonstrating the steps in genetically modified human T lymphocytes with a reporter gene (eGFP) is showin in Figure 2. It is necessary to activate T cells in order to get them to divide, expand, and propagate in culture. Modified human T cells were then cultured and analyzed using flow cyt...

Watch this Scientific Journal Video about piggyBac Transposon System Modification of Primary Human T Cells at JoVE.com

piggyBac Transposon System Modification of Primary Human T Cells

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.

piggyBac Transposon System Modification of Primary Human T Cells

The piggyBac transposon system is naturally active, originally derived from the cabbage looper moth1,2. This non-viral system is plasmid based, most ...

piggybac-transposon-system-modification-of-primary-human-t-cells

Research

JoVE Journal

Immunology and Infection

17.1K Views.  Baylor College of Medicine. 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.

Video: piggyBac Transposon System Modification of Primary Human T Cells

Expansion of Human Peripheral Blood  &gamma;&delta; T Cells using Zoledronate

Human &gamma;&delta; T cells can recognize and respond to a wide variety of stress-induced antigens, thereby developing innate broad anti-tumor and anti-infective activity.1 The majority of &gamma;&delta; T cells in peripheral blood have the V&gamma;9V&delta;2 T cell receptor. These cells recognize antigen in a major histocompatibility complex-independent manner and develop strong cytolytic and Th1-like effector functions.1Therefore, &gamma;&delta; T cells are attractive candidate effector cells for cancer immunotherapy. V&gamma;9V&#x03B4;2 T cells respond to phosphoantigens such as (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), which is synthesized in bacteria via isoprenoid biosynthesis;2 and isopentenyl pyrophosphate (IPP), which is produced in eukaryotic cells through the mevalonate pathway.3 In physiological condition, the generation of IPP in nontransformed cell is not sufficient for the activation of &gamma;&delta; T cells. Dysregulation of mevalonate pathway in tumor cells leads to accumulation of IPP and &gamma;&delta; T cells activation.3 Because aminobisphosphonates (such as pamidronate or zoledronate) inhibit farnesyl pyrophosphate synthase (FPPS), the enzyme acting downstream of IPP in the mevalonate pathway, intracellular levels of IPP and sensitibity to &gamma;&delta; T cells recognition can be therapeutically increased by aminobisphosphonates. IPP accumulation is less efficient in nontransfomred cells than tumor cells with a pharmacologically relevant concentration of aminobisphosphonates, that allow us immunotherapy for cancer by activating &gamma;&delta; T cells with aminobisphosphonates. 4 Interestingly, IPP accumulates in monocytes when PBMC are treated with aminobisphosphonates, because of efficient drug uptake by these cells. 5 Monocytes that accumulate IPP become antigen-presenting cells and stimulate V&gamma;9V&delta;2 T cells in the peripheral blood.6 Based on these mechanisms, we developed a technique for large-scale expansion of &gamma;&delta; T cell cultures using zoledronate and interleukin-2 (IL-2).7 Other methods for expansion of &gamma;&delta; T cells utilize the synthetic phosphoantigens bromohydrin pyrophosphate (BrHPP)8 or 2-methyl-3-butenyl-1-pyrophosphate (2M3B1PP).9 All of these methods allow ex vivo expansion, resulting in large numbers of &gamma;&delta; T cells for use in adoptive immunotherapy. However, only zoledronate is an FDA-approved commercially available reagent. Zoledronate-expanded &gamma;&delta; T cells display CD27-CD45RA- effector memory phenotype and thier function can be evaluated by IFN-&gamma; production assay. 7

Expansion of Human Peripheral Blood  &amp;#947;&amp;#948; T Cells using Zoledronate

A method to expand &gamma;&delta; T cells from peripheral blood mononuclear cells (PBMC) is described. PBMC-derived &gamma;&delta; T cells are stimulated and expanded using zoledronate and interleukin-2 (IL-2). Large scale expansion of &gamma;&delta; T cells can be applied to autologous cellular immunotherapy of cancer.

Human &gamma;&delta; T cells can recognize and respond to a wide variety of stress-induced antigens, thereby developing innate broad anti-tumor and ...

Determining Optimal Cytotoxic Activity of Human Her2neu Specific CD8 T cells by Comparing the Cr51 Release Assay to the xCELLigence System

Cytotoxic CD8 T cells constitute a subgroup of T cells that are capable of inducing the death of infected or malignant host cells1. These cells express a specialized receptor, called the T cell receptor (TCR), which can recognize a specific antigenic peptide bound to HLA class I molecules2. Engagement of infected cells or tumor cells through their HLA class I molecule results in production of lytic molecules such as granzymes and perforin resulting in target cell death. While it is useful to determine frequencies of antigen-specific CD8 T cells using assays such as the ELIspot or flow cytometry, it is also helpful to ascertain the strength of CD8 T cell responses using cytotoxicity assays3. The most recognizable assay for assessing cytotoxic function is the Chromium Release Assay (CRA), which is considered a standard assay 4. The CRA has several limitations, including exposure of cells to gamma radiation, lack of reproducibility, and a requirement for large numbers of cells. Over the past decade, there has been interest in adopting new strategies to overcome these limitations. Newer approaches include those that measure caspase 
release 4, BLT esterase activity 5 and surface expression of CD107 6. The impedance-based assay, using the Roche xCelligence system, was examined in the present paper for its potential as an alternative to the CRA. Impedance or opposition to an electric current occurs when adherent tumor cells bind to electrode plates. Tumor cells detach following killing and electrical impedance is reduced which can be measured by the xCelligence system. The ability to adapt the impedance-based approach to assess cell-mediated killing rests on the observation that T cells do not adhere tightly to most surfaces and do not appear to have much impact on impedance thus diminishing any concern of direct interference of the T cells with the measurement. Results show that the impedance-based assay can detect changes in the levels of antigen-specific cytotoxic CD8 T cells with increased sensitivity relative to the standard CRA. Based on these results, impedance-based approaches may be good alternatives to CRAs or other approaches that aim to measure cytotoxic CD8 T cell functionality.

The chromium release assay, a common assay for detecting cytotoxic T cell activity, has several limitations. Using antigen-specific CD8 T cells and the human breast cancer tumor line, SKBR3, in the present article, an impedance-based approach was examined for the capability of detecting cell killing.

Cytotoxic CD8 T cells constitute a subgroup of T  cells that are capable of inducing the death of infected or malignant host  cells1. These cells express ...

Generation of Induced Regulatory T Cells from Primary Human Na&iuml;ve and Memory T Cells

The development and maintenance of immunosuppressive CD4+ regulatory T cells (Tregs) contribute to the peripheral tolerance needed to remain in immunologic homeostasis with the vast amount of self and commensal antigens in and on the human body. Perturbations in the balance between Tregs and inflammatory conventional T cells can result in immunopathology or cancer. Although therapeutic injection of Tregs has been shown to be efficacious in murine models of colitis1 , type I diabetes2 , rheumatoid arthritis and graft versus host disease,4 several fundamental differences in human versus mouse Treg biology5 has thus far precluded clinical use. The lack of sufficient number, purity, stability and homing specificity of therapeutic Tregs necessitated a dynamic platform of human Treg development on which to optimize conditions for their ex vivo expansion6.
Here we describe a method for the differentiation of induced Tregs (iTregs) from a single human peripheral blood donor which can be broken down into four stages: isolation of peripheral blood mononuclear cells, magnetic selection of CD4+ T cells, in vitro cell culture and fluorescence activated cell sorting (FACS) of T cell subsets. Since the Treg signature transcription factor forkhead box P3 (FoxP3) is an activation-induced transcription factor in humans7 and no other unique marker exists, a combinatorial panel of markers must be used to identify T cells with suppressor activity. After six days in culture, cells in our system can be demarcated into na&iuml;ve T cells, memory T cells or iTregs based on their relative expression of CD25 and CD45RA. As memory and na&iuml;ve T cells have different reported polarization requirements and plasticities8 , pre-sorting of the initial T cell population into CD45RA+ and CD45RO+ subsets can be used to examine these discrepancies. Consistent with others, our CD25HiCD45RA- iTregs express high levels of FoxP39 , GITR and CTLA-411 and low levels of CD12712 . Following FACS of each population, resultant cells can be used in a suppressor assay which evaluates the relative ability to retard the proliferation of carboxyfluorescein succinimidyl ester (CFSE)-labeled autologous T cells.

Generation of Induced Regulatory T Cells from Primary Human Na&amp;#239;ve and Memory T Cells

We describe a method for generating regulatory, memory and na&#239;ve T cells from a single human blood donor. Polarized Tregs can be then compared to other subsets in a variety of genetic and functional applications with genetic homogeneity, including a suppression assay also detailed here.

The development and maintenance of immunosuppressive CD4+ regulatory T cells (Tregs) contribute to the peripheral tolerance needed to remain in ...

Assessing the Innate Sensing of HIV-1 Infected CD4+ T Cells by Plasmacytoid Dendritic Cells Using an Ex vivo Co-culture System.

HIV-1 innate sensing requires direct contact of infected CD4+ T cells with plasmacytoid dendritic cells (pDCs). In order to study this process, the protocols described here use freshly isolated human peripheral blood mononuclear cells (PBMCs) or plasmacytoid dendritic cells (pDCs) to sense infections in either T cell line (MT4) or heterologous primary CD4+ T cells. In order to ensure proper sensing, it is essential that PBMC are isolated immediately after blood collection and that optimal percentage of infected T cells are used. Furthermore, multi-parametric flow cytometric staining can be used to confirm that PBMC samples contain the different cell lineages at physiological ratios. A number of controls can also be included to evaluate viability and functionality of pDCs. These include, the presence of specific surface markers, assessing cellular responses to known agonist of Toll-Like Receptors (TLR) pathways, and confirming a lack of spontaneous type-I interferon (IFN) production. In this system, freshly isolated PBMCs or pDCs are co-cultured with HIV-1 infected cells in 96 well plates for 18-22 hr. Supernatants from these co-cultures are then used to determine the levels of bioactive type-I IFNs by monitoring the activation of the ISGF3 pathway in HEK-Blue IFN-&#945;/&#946; cells. Prior and during co-culture conditions, target cells can be subjected to flow cytometric analysis to determine a number of parameters, including the percentage of infected cells, levels of specific surface markers, and differential killing of infected cells. Although, these protocols were initially developed to follow type-I IFN production, they could potentially be used to study other imuno-modulatory molecules released from pDCs and to gain further insight into the molecular mechanisms governing HIV-1 innate sensing.

Assessing the Innate Sensing of HIV-1 Infected CD4+ T Cells by Plasmacytoid Dendritic Cells Using an Ex vivo Co-culture System.

Unlike cell-free HIV-1 particles, infected CD4+ T cells are effectively sensed by plasmacytoid dendritic cells (pDCs). This manuscript describes a method where peripheral blood mononuclear cells (PBMCs) or isolated pDCs are co-cultured with HIV-1 infected T cells to evaluate innate sensing by pDCs as assessed by release of type-I IFN.

HIV-1 innate sensing requires direct contact of infected CD4+ T cells with plasmacytoid dendritic cells (pDCs). In order to study this process, the ...

Identification of Novel Genes Associated with Alginate Production in Pseudomonas aeruginosa Using Mini-himar1 Mariner Transposon-mediated Mutagenesis

Pseudomonas aeruginosa is a Gram-negative, environmental bacterium with versatile metabolic capabilities. P. aeruginosa is an opportunistic bacterial pathogen which establishes chronic pulmonary infections in patients with cystic fibrosis (CF). The overproduction of a capsular polysaccharide called alginate, also known as mucoidy, promotes the formation of mucoid biofilms which are more resistant than planktonic cells to antibiotic chemotherapy and host defenses. Additionally, the conversion from the nonmucoid to mucoid phenotype is a clinical marker for the onset of chronic infection in CF. Alginate overproduction by P. aeruginosa is an endergonic process which heavily taxes cellular energy. Therefore, alginate production is highly regulated in P. aeruginosa. To better understand alginate regulation, we describe a protocol using the mini-himar1 transposon mutagenesis for the identification of novel alginate regulators in a prototypic strain PAO1. The procedure consists of two basic steps. First, we transferred the mini-himar1 transposon (pFAC) from host E. coli SM10/&#955;pir into recipient P. aeruginosa PAO1 via biparental conjugation to create a high-density insertion mutant library, which were selected on Pseudomonas isolation agar plates supplemented with gentamycin. Secondly, we screened and isolated the mucoid colonies to map the insertion site through inverse PCR using DNA primers pointing outward from the gentamycin cassette and DNA sequencing. Using this protocol, we have identified two novel alginate regulators, mucE (PA4033) and kinB (PA5484), in strain PAO1 with a wild-type mucA encoding the anti-sigma factor MucA for the master alginate regulator AlgU (AlgT, &#963;22). This high-throughput mutagenesis protocol can be modified for the identification of other virulence-related genes causing change in colony morphology.

Identification of Novel Genes Associated with Alginate Production in Pseudomonas aeruginosa Using Mini-himar1 Mariner Transposon-mediated Mutagenesis

Here we describe a protocol using the mini-himar1 mariner transposon-mediated mutagenesis for generating a high-density insertion mutant library to screen, isolate and identify novel alginate regulators in the prototypic Pseudomonas aeruginosa strain PAO1.

Pseudomonas aeruginosa is a Gram-negative, environmental bacterium with versatile metabolic capabilities. P. aeruginosa is an opportunistic bacterial ...

Generation of Human Alloantigen-specific T Cells from Peripheral Blood

The study of human T lymphocyte biology often involves examination of responses to activating ligands. T cells recognize and respond to processed peptide antigens presented by MHC (human ortholog HLA) molecules through the T cell receptor (TCR) in a highly sensitive and specific manner. While the primary function of T cells is to mediate protective immune responses to foreign antigens presented by self-MHC, T cells respond robustly to antigenic differences in allogeneic tissues. T cell responses to alloantigens can be described as either direct or indirect alloreactivity. In alloreactivity, the T cell responds through highly specific recognition of both the presented peptide and the MHC molecule. The robust oligoclonal response of T cells to allogeneic stimulation reflects the large number of potentially stimulatory alloantigens present in allogeneic tissues. While the breadth of alloreactive T cell responses is an important factor in initiating and mediating the pathology associated with biologically-relevant alloreactive responses such as graft versus host disease and allograft rejection, it can preclude analysis of T cell responses to allogeneic ligands. To this end, this protocol describes a method for generating alloreactive T cells from naive human peripheral blood leukocytes (PBL) that respond to known peptide-MHC (pMHC) alloantigens. The protocol applies pMHC multimer labeling, magnetic bead enrichment and flow cytometry to single cell in vitro culture methods for the generation of alloantigen-specific T cell clones. This enables studies of the biochemistry and function of T cells responding to allogeneic stimulation.

This article describes a method for the generation and propagation of human T cell clones that specifically respond to a defined alloantigen. This protocol can be adapted for cloning human T cells specific for a variety of peptide-MHC ligands.

The study of human T lymphocyte biology often involves examination of responses to activating ligands. T cells recognize and respond to processed peptide ...

Assessment of the Synaptic Interface of Primary Human T Cells from Peripheral Blood and Lymphoid Tissue

The current understanding of the dynamics and structural features of T-cell synaptic interfaces has been largely determined through the use of glass-supported planar bilayers and in vitro-derived T-cell clones or lines1,2,3,4. How these findings apply to the primary human T cells isolated from blood or lymphoid tissues is not known, partly due to significant difficulties in obtaining a sufficient number of cells for analysis5. Here we address this through the development of a technique exploiting multichannel flow slides to build planar lipid bilayers containing activating and adhesion molecules. The low height of the flow slides promotes rapid cell sedimentation in order to synchronize cell:bilayer attachment, thereby allowing researchers to study the dynamic of the synaptic interface formation and the kinetics of the granules release. We apply this approach to analyze the synaptic interface of as few as 104 to 105 primary cryopreserved T cells isolated from lymph nodes (LN) and peripheral blood (PB). The results reveal that the novel planar lipid bilayer technique enables the study of the biophysical properties of primary human T cells derived from blood and tissues in the context of health and disease.

The protocol describes a technique to study the ability of primary polyclonal human T cells to form synaptic interfaces using planar lipid bilayers. We use this technique to show the differential synapse formation capability of human primary T cells derived from lymph nodes and peripheral blood.

The current understanding of the dynamics and structural features of T-cell synaptic interfaces has been largely determined through the use of ...

Pneumococcus Infection of Primary Human Endothelial Cells in Constant Flow

Interaction of Streptococcus pneumoniae with the surface of endothelial cells is mediated in blood flow via mechanosensitive proteins such as the Von Willebrand Factor (VWF). This glycoprotein changes its molecular conformation in response to shear stress, thereby exposing binding sites for a broad spectrum of host-ligand interactions. In general, culturing of primary endothelial cells under a defined shear flow is known to promote the specific cellular differentiation and the formation of a stable and tightly linked endothelial layer resembling the physiology of the inner lining of a blood vessel. Thus, the functional analysis of interactions between bacterial pathogens and the host vasculature involving mechanosensitive proteins requires the establishment of pump systems that can simulate the physiological flow forces known to affect the surface of vascular cells.
The microfluidic device used in this study enables a continuous and pulseless recirculation of fluids with a defined flow rate. The computer-controlled air-pressure pump system applies a defined shear stress on endothelial cell surfaces by generating a continuous, unidirectional, and controlled medium flow. Morphological changes of the cells and bacterial attachment can be microscopically monitored and quantified in the flow by using special channel slides that are designed for microscopic visualization. In contrast to static cell culture infection, which in general requires a sample fixation prior to immune labeling and microscopic analyses, the microfluidic slides enable both the fluorescence-based detection of proteins, bacteria, and cellular components after sample fixation; serial immunofluorescence staining; and direct fluorescence-based detection in real time. In combination with fluorescent bacteria and specific fluorescence-labeled antibodies, this infection procedure provides an efficient multiple component visualization system for a huge spectrum of scientific applications related to vascular processes.

This study describes the microscopic monitoring of pneumococcus adherence to von Willebrand factor strings produced on the surface of differentiated human primary endothelial cells under shear stress in defined flow conditions. This protocol can be extended to detailed visualization of specific cell structures and quantification of bacteria by applying differential immunostaining procedures.

Interaction of Streptococcus pneumoniae with the surface of endothelial cells is mediated in blood flow via mechanosensitive proteins such as the Von ...

Production of Human CRISPR-Engineered CAR-T Cells

Adoptive cell therapies using chimeric antigen receptor T cells (CAR-T cells) have demonstrated remarkable clinical efficacy in patients with hematological malignancies and are currently being investigated for various solid tumors. CAR-T cells are generated by removing T cells from a patient's blood and engineering them to express a synthetic immune receptor that redirects the T-cells to recognize and eliminate target tumor cells. Gene editing of CAR-T cells has the potential to improve safety of current CAR-T cell therapies and further increase the efficacy of CAR-T cells. Here, we describe methods for the activation, expansion, and characterization of human CRISPR-engineered CD19 directed CAR-T cells. This comprises transduction of the CAR lentiviral vector and use of single guide RNA (sgRNA) and Cas9 endonuclease to target genes of interest in T cells. The methods described in this protocol can be universally applied to other CAR constructs and target genes beyond the ones used for this study. Furthermore, this protocol discusses strategies for gRNA design, lead gRNA selection and target gene knockout validation to reproducibly achieve high-efficiency, multiplex CRISPR-Cas9 engineering of clinical grade human T cells.

Here, we present a protocol for gene editing in primary human T cells using CRISPR Cas Technology to modify CAR-T cells.

Adoptive cell therapies using chimeric antigen receptor T cells (CAR-T cells) have demonstrated remarkable clinical efficacy in patients with ...

Real-time Monitoring of Mitochondrial Respiration in Cytokine-differentiated Human Primary T Cells

During activation, the metabolism of T cells adapts to changes that impact their fate. An increase in mitochondrial oxidative phosphorylation is indispensable for T cell activation, and the survival of memory T cells is dependent on mitochondrial remodeling. Consequently, this affects the long-term clinical outcome of cancer immunotherapies. Changes in T cell quality are often studied by flow cytometry using well-known surface markers and not directly by their metabolic state. This is an optimized protocol for measuring real-time mitochondrial respiration of primary human T cells using an Extracellular Flux Analyzer and the cytokines IL-2 and IL-15, which differently affect T cell metabolism. It is shown that the metabolic state of T cells can clearly be distinguished by measuring the oxygen consumption when inhibiting key complexes in the metabolic pathway and that the accuracy of these measurements is highly dependent on optimal inhibitor concentration and inhibitor injection strategy. This standardized protocol will help implement mitochondrial respiration as a standard for T cell fitness in monitoring and studying cancer immunotherapies.

Metabolic adaptation is fundamental for T cells as it dictates differentiation, persistence, and cytotoxicity. Here, an optimized protocol for monitoring mitochondrial respiration in ex vivo cytokine-differentiated human primary T cells is presented.