The authors would like to thank Lirui Du for constructing the pCAGAdDU vector and Oliver Gorka for provision of the fixation protocol.

1. Cloning of a Gene of Interest into an Entry Vector
<ol>
	<li>Clone the gene of interest into an entry vector. PCR amplification of the gene followed by blunt-end ligation into a topoisomerase-coupled vector (e.g. pENTR/D-TOPO) or restriction enzyme-mediated cloning may be used for this procedure.</li>
</ol>
2. Transferring the Gene of Interest into the pCAGAdDu Destination Vector
<ol>
	<li>Transfer the gene of interest from the entry vector into the destination vector by LR recombi...

<ol>
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L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activation+of+CD25(+)CD4(+)+regulatory+T+cells+by+oral+antigen+administration.">Activation of CD25(+)CD4(+) regulatory T cells by oral antigen administration.</a> Journal of Immunology (Baltimore, Md). 167 (8), 4245-4253 (2001).</li><li>Josefowicz, S. Z., Niec, R. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extrathymically+generated+regulatory+T+cells+control+mucosal+TH2+inflammation.">Extrathymically generated regulatory T cells control mucosal TH2 inflammation.</a> Nature. 482 (7385), 395-399 (2012).</li><li>Samstein, R. M., Josefowicz, S. Z., Arvey, A., Treuting, P. M., Rudensky, A. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extrathymic+generation+of+regulatory+T+cells+in+placental+mammals+mitigates+maternal-fetal+conflict.">Extrathymic generation of regulatory T cells in placental mammals mitigates maternal-fetal conflict.</a> Cell. 150 (1), 29-38 (2012).</li><li>Laurence, A., Amarnath, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=STAT3+Transcription+Factor+Promotes+Instability+of+nTreg+Cells+and+Limits+Generation+of+iTreg+Cells+during+Acute+Murine+Graft-versus-Host+Disease.">STAT3 Transcription Factor Promotes Instability of nTreg Cells and Limits Generation of iTreg Cells during Acute Murine Graft-versus-Host Disease.</a> Immunity. 37 (2), 209-222 (2012).</li><li>Terabe, M., Berzofsky, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunoregulatory+T+cells+in+tumor+immunity.">Immunoregulatory T cells in tumor immunity.</a> Current Opinion in Immunology. 16 (2), 157-162 (2004).</li><li>Li, X., Kostareli, E., Suffner, J., Garbi, N., H&#228;mmerling, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+Treg+depletion+induces+T-cell+infiltration+and+rejection+of+large+tumors.">Efficient Treg depletion induces T-cell infiltration and rejection of large tumors.</a> European Journal of Immunology. 40 (12), 3325-3335 (2010).</li><li>Fontenot, J. D., Gavin, M. A., Rudensky, A. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Foxp3+programs+the+development+and+function+of+CD4+CD25++regulatory+T+cells.">Foxp3 programs the development and function of CD4+CD25+ regulatory T cells.</a> Nature Immunology. 4 (4), 330-336 (2003).</li><li>Hori, S., Nomura, T., Sakaguchi, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+regulatory+T+cell+development+by+the+transcription+factor+Foxp3.">Control of regulatory T cell development by the transcription factor Foxp3.</a> Science. 299 (5609), 1057-1061 (2003).</li><li>Chen, W., Jin, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conversion+of+Peripheral+CD4+CD25-+Naive+T+Cells+to+CD4+CD25++Regulatory+T+Cells+by+TGF-&#946;+Induction+of+Transcription+Factor+Foxp3.">Conversion of Peripheral CD4+CD25- Naive T Cells to CD4+CD25+ Regulatory T Cells by TGF-&#946; Induction of Transcription Factor Foxp3.</a> The Journal of Experimental Medicine. 198 (12), 1875-1886 (2003).</li><li>Xu, W., Lan, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adoptive+transfer+of+induced-treg+cells+effectively+attenuates+murine+airway+allergic+inflammation.">Adoptive transfer of induced-treg cells effectively attenuates murine airway allergic inflammation.</a> PloS ONE. 7 (7), e40314 (2012).</li><li>Circosta, P., Granziero, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=T+cell+receptor+(TCR)+gene+transfer+with+lentiviral+vectors+allows+efficient+redirection+of+tumor+specificity+in+naive+and+memory+T+cells+without+prior+stimulation+of+endogenous+TCR.">T cell receptor (TCR) gene transfer with lentiviral vectors allows efficient redirection of tumor specificity in naive and memory T cells without prior stimulation of endogenous TCR.</a> Human Gene Therapy. 20 (12), 1576-1588 (2009).</li><li>Patel, C., Muthuswamy, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+efficiency,+Site-specific+Transfection+of+Adherent+Cells+with+siRNA+Using+Microelectrode+Arrays+(MEA).">High efficiency, Site-specific Transfection of Adherent Cells with siRNA Using Microelectrode Arrays (MEA).</a> J. Vis. Exp. (67), e4415 (2012).</li><li>Zhong, S., Malecek, K., Perez-Garcia, A., Krogsgaard, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retroviral+transduction+of+T-cell+receptors+in+mouse+T-cells.">Retroviral transduction of T-cell receptors in mouse T-cells.</a> J. Vis. Exp. (44), e2307 (2010).</li><li>Leon, R. P., Hedlund, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adenoviral-mediated+gene+transfer+in+lymphocytes.">Adenoviral-mediated gene transfer in lymphocytes.</a> Proceedings of the National Academy of Sciences of the United States of America. 95 (22), 13159-13164 (1998).</li><li>Wan, Y. Y., Leon, R. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transgenic+expression+of+the+coxsackie/adenovirus+receptor+enables+adenoviral-mediated+gene+delivery+in+naive+T+cells.">Transgenic expression of the coxsackie/adenovirus receptor enables adenoviral-mediated gene delivery in naive T cells.</a> Proceedings of the National Academy of Sciences of the United States of America. 97 (25), 13784-13789 (2000).</li><li>Hurez, V., Dzialo-Hatton, R., Oliver, J., Matthews, R. J., Weaver, C. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+adenovirus-mediated+gene+transfer+into+primary+T+cells+and+thymocytes+in+a+new+coxsackie/adenovirus+receptor+transgenic+model.">Efficient adenovirus-mediated gene transfer into primary T cells and thymocytes in a new coxsackie/adenovirus receptor transgenic model.</a> BMC Immunology. 3, 4 (2002).</li><li>Eitelhuber, A. C., Warth, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dephosphorylation+of+Carma1+by+PP2A+negatively+regulates+T-cell+activation.">Dephosphorylation of Carma1 by PP2A negatively regulates T-cell activation.</a> The EMBO Journal. 30 (3), 594-605 (2011).</li><li>Glasmacher, E., Hoefig, K. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Roquin+binds+inducible+costimulator+mRNA+and+effectors+of+mRNA+decay+to+induce+microRNA-independent+post-transcriptional+repression.">Roquin binds inducible costimulator mRNA and effectors of mRNA decay to induce microRNA-independent post-transcriptional repression.</a> Nature Immunology. 11 (8), 725-733 (2010).</li><li>Russell, W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Update+on+adenovirus+and+its+vectors.">Update on adenovirus and its vectors.</a> The Journal of General Virology. 81 (Pt. 11), 2573-2604 (2000).</li><li>Graham, F. L., Smiley, J., Russell, W. C., Nairn, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characteristics+of+a+Human+Cell+Line+Transformed+by+DNA+from+Human+Adenovirus+Type+5.">Characteristics of a Human Cell Line Transformed by DNA from Human Adenovirus Type 5.</a> Journal of General Virology. 36 (1), 59-72 (1977).</li><li>Landy, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic,+structural,+and+regulatory+aspects+of+lambda+site-specific+recombination.">Dynamic, structural, and regulatory aspects of lambda site-specific recombination.</a> Annual Review of Biochemistry. 58, 913-949 (1989).</li><li>Bernard, P., Couturier, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+killing+by+the+F+plasmid+CcdB+protein+involves+poisoning+of+DNA-topoisomerase+II+complexes.">Cell killing by the F plasmid CcdB protein involves poisoning of DNA-topoisomerase II complexes.</a> Journal of Molecular Biology. 226 (3), 735-745 (1992).</li><li>Thai, T. -. H., Calado, D. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+the+Germinal+Center+Response+by+MicroRNA-155.">Regulation of the Germinal Center Response by MicroRNA-155.</a> Science. 316 (5824), 604-608 (2007).</li><li>Rodriguez, A., Vigorito, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Requirement+of+bic/microRNA-155+for+Normal+Immune+Function.">Requirement of bic/microRNA-155 for Normal Immune Function.</a> Science. 316 (5824), 608-611 (2007).</li><li>Cobb, B. S., Hertweck, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+role+for+Dicer+in+immune+regulation.">A role for Dicer in immune regulation.</a> The Journal of Experimental Medicine. 203 (11), 2519-2527 (2006).</li><li>Steiner, D. F., Thomas, M. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MicroRNA-29+Regulates+T-Box+Transcription+Factors+and+Interferon-&#947;+Production+in+Helper+T+Cells.">MicroRNA-29 Regulates T-Box Transcription Factors and Interferon-&#947; Production in Helper T Cells.</a> Immunity. , (2011).</li></ol>

The authors declare no conflict of interest.

Virus Generation and Titration
For optimal transfection results, the quality and amount of linearized vector appear most important. We did not observe negative effects on primary lysate production from an initial overgrowth of the culture since the infection will quickly proceed once efficient virus production occurs. However, virus production by HEK293A cells can be affected by long inserts that decrease the efficiency. Some open reading frames were actually found to interfere with virus product...

Tregs are crucial to maintain immune tolerance and to dampen overshooting immune responses. Tregs suppress bystander T cell activation. Consequently, ablation of Tregs leads to fatal autoimmunity and self-destruction driven by activated T cells1. Tregs develop in the thymus during negative selection of CD4 single-positive precursors, but they can also differentiate in the periphery from naive CD4 T cells upon low-dose antigen stimulation with suboptimal co-stimulation 1,2. Thymic Tregs seem to suppress tissue autoimmunity against self-antigens, whereas peripheral Tregs have been implicated in providing tolerance in the gut or lung. These induced Tregs potently prevent T cell activation after recognition of foreign antigens in the mucosa, including environmental antigens from food and air, commensal bacteria, and allergens 3,4. In addition, Tregs are crucial to establish maternal tolerance to fetal peptides 5 and to prevent graft-versus-host disease 6. At the same time, Tregs also mediate unwanted effects by attenuating immune surveillance of tumor cells 7,8. The hallmark feature of Tregs is the expression of the subset-specifying transcription factor Foxp3, a fork-head domain-containing transcription factor that is necessary and sufficient to confer Treg function 9,10. Some signaling pathways that can induce Foxp3 expression are known. However, the molecular processes that control, regulate, or modulate Treg differentiation in response to T cell receptor triggering are less well understood.
Tregs can very effectively be induced in vitro through the stimulation of naive CD4 T cells with anti-CD3 and anti-CD28 antibodies in the presence of TGF&beta; and IL-2 11. As the emerging Tregs are functional in vivo, the manipulation of molecules that promote Treg differentiation bears enormous potential for future therapies, for example, the treatment of asthma, Crohns disease, and transplantation 11,12. Conversely, therapeutic modulation of molecules to block Treg differentiation may provide benefit in future approaches of combined treatment of tumor patients.
In vitro differentiation assays have been instrumental for the description of molecular changes that are associated with T cell subset differentiation. At the moment, experimental attempts to search or screen for gene products that control T cell differentiation are hampered by the fact that the most common methods of ectopic gene expression fail in naive T cells. For example, electroporation and retroviral transduction are only effective in activated T cells. In contrast to initial expectations, lentiviral transduction, which is typically effective in resting cells, requires pre-activation of naive T cells by cytokines13. Furthermore, the transfer of cDNA or mRNA during electroporation involves depolarization of the plasma membrane, which itself confers features of T cell activation and may even mobilize Ca2+ signaling and activate NFAT proteins (unpublished observation and ref. 14). Similarly, for retroviral transduction, the naive T cells have to be activated for 18 - 40 hr. During this time, the breakdown of the nuclear membrane in the course of cell division occurs and allows for the subsequent genomic integration of the retroviral vector 15. These methods are therefore not able to address the early molecular regulation of initial T cell encounter with antigen, which is the decisive phase of helper T cell differentiation.
Adenoviral transduction is known to confer transient ectopic gene expression in a number of human cell types that express the human Coxsackie adenovirus receptor (CAR). It proceeds without requirement for cell activation or cell-cycle progression. The surface expression of CAR is essential for efficient virus attachment and internalization, and transgenic expression of the truncated version CAR&Delta;1 under a T cell-specific promoter was found to render mouse thymocytes and T cells susceptible to adenoviral infection 16. Importantly, the transgene does not alter thymocyte development or in vitro differentiation of naive CD4 T cells into different subsets (data not shown; ref. 17). Adenovirus-mediated transduction of T cells was previously used for overexpression 17,18 and knock-down approaches 19,20. The transgenic T cells can be purified from commercially available DO11.10 tg; CAR&Delta;1 tg (Taconic, Inc. and ref. 17). Importantly, adenoviral transduction allows high expression of a gene of interest in naive T cells without inducing obvious signs of activation. The T cells remain naive (CD44low, CD62Lhigh) and resting (CD25-, CD69-) after infection and can be activated and differentiated into Treg similar to non-infected cells.
 
Production of recombinant adenoviruses can be achieved after transfection of HEK293A cells with adenoviral plasmids (Figure 1). These plasmids typically contain the human type 5 adenovirus genome with E1 and E3 genes deleted to render recombinant adenoviruses replication-incompetent 21. HEK293A cells complement replication deficiency as they have been immortalized through stable integration of sheared adenovirus 22. Since adenoviral vectors are large (~40 kb) and consequently not well suited for traditional restriction enzyme-mediated cloning, we employed the Gateway system. The gene of interest is initially cloned into a smaller entry vector, from which it can be easily transferred into the adenoviral destination vector via lambda recombination reaction (LR) 23. We constructed the pCAGAdDu vector by combining the CAG promoter (chicken actin promoter and CMV enhancer) with an expression cassette containing LR sites flanking the procaryotic ccdB selection marker 24 . This expression cassette is fused to an internal ribosome entry site (IRES) element that allows coexpression of the eukaryotic infection marker enhanced green fluorescent protein (eGFP), which is fused to a sequence containing the bovine growth hormone poly(A)-signal. We chose the CAG cis-regulatory sequences, since the prototypic CMV promoter was found to be highly activation-dependent and therefore unfavorable for gene expression in naive T cells.
Here, we provide a protocol for efficient in vitro Treg differentiation and a method to transduce naive CD4 T cells without activation (Figure 2). The method enables ectopic gene expression or knock down preceding CD4 T cell differentiation at the naive state. It allows testing the effect of an overexpressed gene of interest during early signaling events upon initial TCR stimulation until T cell subset commitment. Our validation experiments also provide the basis to establish similar adenovirus application in the differentiation of other T cell subsets such as Th1, Th2, Th9, Th17, Th22, or Tfh cells.

<table border="1">
	<tbody>
		<tr>
			<td>Name of the reagent</td>
			<td>Company</td>
			<td>Catalogue number</td>
		</tr>
		<tr>
			<td>pENTR/D-TOPO Cloning Kit</td>
			<td>Invitrogen</td>
			<td>K240020</td>
		</tr>
		<tr>
			<td>Gateway LR Clonase II Enzyme mix</td>
			<td>Invitrogen</td>
			<td>11791020</td>
		</tr>
		<tr>
			<td>PacI</td>
			<td>New England Biolabs</td>
			<td>R057S</td>
		</tr>
		<tr>
			<td>jetPEI</td>
			<td>Polyplus-transfection</td>
			<td>101-10N</td>
		</tr>
		<tr>
			<td>HEK293A Cell Line</td>
			<td>Invitrogen</td>
			<td>R705-07</td>
		</tr>
		<tr>
			<td>A549</td>
			<td>ATCC</td>
			<td>CCL-185</td>
		</tr>
		<tr>
			<td>6-well plates</td>
			<td>BD Falcon</td>
			<td>353046</td>
		</tr>
		<tr>
			<td>14 cm tissue culture dish</td>
			<td>Nunc</td>
			<td>168381</td>
		</tr>
		<tr>
			<td>BALB/cJ-Tg(DO11.10)10Dlo Tg(CAR&Delta;1)1Jdgr</td>
			<td>Taconic Farms</td>
			<td>Model Nr. 4285</td>
		</tr>
		<tr>
			<td>Naive CD4+ T Cell Isolation Kit II</td>
			<td>Miltenyi Biotech</td>
			<td>130-094-131</td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Invitrogen</td>
			<td>41966-052</td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>PAN Biotech</td>
			<td>1502-P110704</td>
		</tr>
		<tr>
			<td>PenStrep</td>
			<td>Invitrogen</td>
			<td>15140-122</td>
		</tr>
		<tr>
			<td>RPMI 1640</td>
			<td>Lonza</td>
			<td>BE12-167F</td>
		</tr>
		<tr>
			<td>NaPyruvate</td>
			<td>Lonza</td>
			<td>BE13-115E</td>
		</tr>
		<tr>
			<td>NEAA 100x</td>
			<td>Lonza</td>
			<td>BE13-114E</td>
		</tr>
		<tr>
			<td>L-Glutamine</td>
			<td>Invitrogen</td>
			<td>25030</td>
		</tr>
		<tr>
			<td>HEPES Buffer Solution (1 M)</td>
			<td>Invitrogen</td>
			<td>15630-056</td>
		</tr>
		<tr>
			<td>&beta;-Mercaptoethanol</td>
			<td>Sigma-Aldrich</td>
			<td>M-7522</td>
		</tr>
		<tr>
			<td>MEM Essential vitamin mixture (100x)</td>
			<td>Lonza</td>
			<td>13-607C</td>
		</tr>
		<tr>
			<td>Dynabeads Mouse T-Activator CD3/CD28 for Cell Expansion and Activation</td>
			<td>Invitrogen</td>
			<td>114-56D</td>
		</tr>
		<tr>
			<td>Recombinant Human TGF-beta 1</td>
			<td>R&amp;D Systems</td>
			<td>240B</td>
		</tr>
		<tr>
			<td>Proleukin S (18 x 106IE)</td>
			<td>Novartis</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>LIVE/DEAD Fixable Blue Dead Cell Stain Kit</td>
			<td>Invitrogen</td>
			<td>L-23105</td>
		</tr>
		<tr>
			<td>Mouse BD Fc BlockT</td>
			<td>BD Pharmingen</td>
			<td>553141</td>
		</tr>
		<tr>
			<td>Anti-Mouse/Rat Foxp3 PE</td>
			<td>eBioscience</td>
			<td>12-5773-82</td>
		</tr>
		<tr>
			<td>Mmu-miR-155 TaqMan MicroRNA Assay</td>
			<td>Roche Applied Biosystems</td>
			<td>4427975</td>
		</tr>
		<tr>
			<td>LightCycler 480 Probes Master</td>
			<td>Roche Applied Biosystems</td>
			<td>04902343001</td>
		</tr>
		<tr>
			<td>TaqMan MicroRNA Reverse Transcription Kit</td>
			<td>Roche Applied Biosystems</td>
			<td>4366596</td>
		</tr>
	</tbody>
</table>

adenoviral transduction of naive cd4 t cells to study treg differentiation

Regulatory T cells (Tregs) are essential to provide immune tolerance to self as well as to certain foreign antigens. Tregs can be generated from naive CD4 T cells in vitro with TCR- and co-stimulation in the presence of TGF&beta; and IL-2. This bears enormous potential for future therapies, however, the molecules and signaling pathways that control differentiation are largely unknown.
Primary T cells can be manipulated through ectopic gene expression, but common methods fail to target the most important naive state of the T cell prior to primary antigen recognition. Here, we provide a protocol to express ectopic genes in naive CD4 T cells in vitro before inducing Treg differentiation. It applies transduction with the replication-deficient adenovirus and explains its generation and production. The adenovirus can take up large inserts (up to 7 kb) and can be equipped with promoters to achieve high and transient overexpression in T cells. It effectively transduces naive mouse T cells if they express a transgenic Coxsackie adenovirus receptor (CAR). Importantly, after infection the T cells remain naive (CD44low, CD62Lhigh) and resting (CD25-, CD69-) and can be activated and differentiated into Tregs similar to non-infected cells. Thus, this method enables manipulation of CD4 T cell differentiation from its very beginning. It ensures that ectopic gene expression is already in place when early signaling events of the initial TCR stimulation induces cellular changes that eventually lead into Treg differentiation.

Virus Production
For generation of high virus titers, the timing of HEK293A cell harvest in primary virus production or virus amplification is crucial. Representative fluorescent and phase contrast images with visual signs of virus production are shown in Figure 3. The CPE were observed 10 days after transfection of HEK293A cells with a control pCAGAdDu vector without insert. CPE are characterized by the appearance of areas with enlarged and round-up cells that start to detach an...

Watch this Scientific Journal Video about Adenoviral Transduction of Naive CD4 T Cells to Study Treg Differentiation at JoVE.com

Adenoviral Transduction of Naive CD4 T Cells to Study Treg Differentiation

Adenoviral gene transfer into naive CD4 T cells with transgenic expression of the Coxsackie adenovirus receptor enables the molecular analysis of regulatory T cell differentiation in vitro.

Regulatory T cells (Tregs) are essential to provide immune tolerance to self as well as to certain foreign antigens. Tregs can be generated from naive CD4 ...

adenoviral-transduction-naive-cd4-t-cells-to-study-treg

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JoVE Journal

Immunology and Infection

15.7K vues.  Helmholtz Zentrum München. Le transfert de gène adénoviral en CD4 des cellules T naïves avec expression transgénique du récepteur de l'adénovirus Coxsackie permet l'analyse moléculaire de la différenciation des cellules T régulatrices In vitro.