Name: t cells capture bacteria by transinfection from dendritic cells
Uploaded: 2016-01-13T13:00:00
Description: Watch this Scientific Journal Video about T Cells Capture Bacteria by Transinfection from Dendritic Cells at JoVE.com

This work was supported by grants BFU2011-29450, BFU2008-04342/BMC from the Spanish Ministry of Science and Innovation and PIES201020I046 from Consejo Superior de Investigaciones Cient&#236;ficas (CSIC).

Note: Experimental procedures were approved by the Committee for Research Ethics of the Universidad Aut&#242;noma de Madrid and conducted under the supervision of the Universidad Aut&#242;noma de Madrid Head of Animal Welfare and Health in accordance with Spanish and European guidelines. Mice were bred in specific pathogen free (SPF) housing and they were euthanized by trained and qualified personnel using carbon dioxide (CO2) inhalation method.
1. Mouse Bone Marrow-derived DCs Differ...

<ol>
	<li>Medzhitov, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recognition+of+microorganisms+and+activation+of+the+immune+response.">Recognition of microorganisms and activation of the immune response.</a> Nature. 449 (7164), 819-826 (2007).</li><li>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Molecular biology of the cell. , (1989).</li><li>Pancer, Z., Cooper, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+evolution+of+adaptive+immunity.">The evolution of adaptive immunity.</a> Annual Review of Immunology. 24, 497-518 (2006).</li><li>Rhoades, R. A., Bell, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Medical Phisiology. , (2012).</li><li>Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+Invasion:+The+Paradigms+of+Enteroinvasive+Pathogens.">Bacterial Invasion: The Paradigms of Enteroinvasive Pathogens.</a> Science. 304 (5668), 242-248 (2004).</li><li>Kaufmann, S. H., Schaible, U. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antigen+presentation+and+recognition+in+bacterial+infections.">Antigen presentation and recognition in bacterial infections.</a> Current Opinion in Immunology. 17 (1), 79-87 (2005).</li><li>Pizarro-Cerd&#225;, J., Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+Adhesion+and+Entry+into+Host+Cells.">Bacterial Adhesion and Entry into Host Cells.</a> Cell. 124 (4), 715-727 (2006).</li><li>Dustin, M. L. <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+activation+through+immunological+synapses+and+kinapses.">T-cell activation through immunological synapses and kinapses.</a> Immunological Reviews. 221, 77-89 (2008).</li><li>Calabia-Linares, C., Robles-Valero, J., 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=Endosomal+clathrin+drives+actin+accumulation+at+the+immunological+synapse.">Endosomal clathrin drives actin accumulation at the immunological synapse.</a> Journal of Cell Science. 124 (5), 820-830 (2011).</li><li>Westcott, M. M., Henry, C. J., Cook, A. S., Grant, K. W., Hiltbold, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+susceptibility+of+bone+marrow-derived+dendritic+cells+and+macrophages+to+productive+infection+with+Listeria+monocytogenes.">Differential susceptibility of bone marrow-derived dendritic cells and macrophages to productive infection with Listeria monocytogenes.</a> Cellular Microbiology. 9 (6), 1397-1411 (2007).</li><li>Geijtenbeek, T. B., Kwon, D. 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=DC-SIGN,+a+dendritic+cell-specific+HIV-1-binding+protein+that+enhances+trans-infection+of+T+cells.">DC-SIGN, a dendritic cell-specific HIV-1-binding protein that enhances trans-infection of T cells.</a> Cell. 100 (5), 587-597 (2000).</li><li>Izquierdo-Useros, N., Naranjo-G&#242;mez, M., 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=HIV+and+mature+dendritic+cells:+Trojan+exosomes+riding+the+Trojan+horse.">HIV and mature dendritic cells: Trojan exosomes riding the Trojan horse.</a> PLoS Pathogens. 6 (3), e1000740 (2010).</li><li>Mittelbrunn, M., Sanchez-Madrid, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intercellular+communication:+diverse+structures+for+exchange+of+genetic+information.">Intercellular communication: diverse structures for exchange of genetic information.</a> Nature Reviews. Molecular cell biology. 13 (5), 328-335 (2012).</li><li>McElroy, D. S., Ashley, T. J., D'Orazio, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lymphocytes+serve+as+a+reservoir+for+Listeria+monocytogenes+growth+during+infection+of+mice.">Lymphocytes serve as a reservoir for Listeria monocytogenes growth during infection of mice.</a> Microbial Pathogenesis. 46 (4), 214-221 (2009).</li><li>Salgado-Pabon, W., Celli, 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=Shigella+impairs+T+lymphocyte+dynamics+in+vivo.">Shigella impairs T lymphocyte dynamics in vivo.</a> Proceedings of the National Academy of Sciences. 110 (12), 4458-4463 (2013).</li><li>Cruz Adalia, A., Ramirez-Santiago, G., 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+cells+kill+bacteria+captured+by+transinfection+from+dendritic+cells+and+confer+protection+in+mice.">T cells kill bacteria captured by transinfection from dendritic cells and confer protection in mice.</a> Cell Host and Microbe. 15 (5), 611-622 (2014).</li><li>Barnden, M. J., Allison, J., Heath, W. R., Carbone, F. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defective+TCR+expression+in+transgenic+mice+constructed+using+cDNA-based+alpha-+and+beta-chain+genes+under+the+control+of+heterologous+regulatory+elements.">Defective TCR expression in transgenic mice constructed using cDNA-based alpha- and beta-chain genes under the control of heterologous regulatory elements.</a> Immunology and Cell Biology. 76 (1), 34-40 (1998).</li><li>Matheu, M. P., Sen, D., Cahalan, M. D., Parker, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+bone+marrow+derived+murine+dendritic+cells+for+use+in+2-photon+imaging.">Generation of bone marrow derived murine dendritic cells for use in 2-photon imaging.</a> Journal of Visualized Experiments: JoVE. (17), (2008).</li><li>Inaba, K., Inaba, M., 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=Generation+of+large+numbers+of+dendritic+cells+from+mouse+bone+marrow+cultures+supplemented+with+granulocyte/macrophage+colony-stimulating+factor.">Generation of large numbers of dendritic cells from mouse bone marrow cultures supplemented with granulocyte/macrophage colony-stimulating factor.</a> Journal of Experimental Medicine. 176 (6), 1693-1702 (1992).</li><li>Th&#246;ne, F., Schwanh&#228;usser, B., Becker, D., Ballmaier, M., Bumann, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FACS-isolation+of+Salmonella-infected+cells+with+defined+bacterial+load+from+mouse+spleen.">FACS-isolation of Salmonella-infected cells with defined bacterial load from mouse spleen.</a> Journal of Microbiological Methods. 71 (3), 220-224 (2007).</li><li>Vaudaux, P., Waldvogel, F. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gentamicin+antibacterial+activity+in+the+presence+of+human+polymorphonuclear+leukocytes.">Gentamicin antibacterial activity in the presence of human polymorphonuclear leukocytes.</a> Antimicrobial Agents and Chemotherapy. 16 (6), 743-749 (1979).</li><li>Zhang, X., Goncalves, R., Mosser, D. M., Coligan, 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=Chapter+14,+The+isolation+and+characterization+of+murine+macrophages.">Chapter 14, The isolation and characterization of murine macrophages.</a> Current protocols in immunology. , Unit 14.1 (2008).</li><li>Bedoya, S. K., Wilson, T. D., Collins, E. L., Lau, K., Larkin, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+th17+differentiation+of+na&#239;ve+CD4+T+lymphocytes.">Isolation and th17 differentiation of na&#239;ve CD4 T lymphocytes.</a> Journal of Visualized Experiments: JoVE. (79), e50765 (2013).</li><li>Basu, S., Campbell, H. M., Dittel, B. N., Ray, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+of+specific+cell+population+by+fluorescence+activated+cell+sorting+(FACS).">Purification of specific cell population by fluorescence activated cell sorting (FACS).</a> Journal of Visualized Experiments: JoVE. (41), (2010).</li><li>Foucar, K., Chen, I. M., Crago, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organization+and+operation+of+a+flow+cytometric+immunophenotyping+laboratory.">Organization and operation of a flow cytometric immunophenotyping laboratory.</a> Seminars in diagnostic pathology. 6 (1), 13-36 (1989).</li><li>Itano, A. A., Jenkins, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antigen+presentation+to+naive+CD4+T+cells+in+the+lymph+node.">Antigen presentation to naive CD4 T cells in the lymph node.</a> Nature Immunology. 4 (8), 733-739 (2003).</li></ol>

T cells or T lymphocytes are a type of leukocytes that play a central role in cell-mediated immunity and belong to the adaptive immune response26. T cells are refractory to being infected in vitro but some reports indicate that they can be infected in vivo14,15. The intimate contacts of APC and T cells during immune synapse serve as platforms for exchanging biological material13, including some viruses such as HIV11. It was recently shown that contrary to the ...

When a pathogen infects its host, there is usually an activation of the innate and adaptive immune responses, necessary for bacterial clearance. Innate immunity is the first line of defense that prevents most infections. Innate immunity distinguish in a precise way elements that are conserved among broad groups of microorganisms (pathogen-associated molecular patterns, PAMPS)1. The mechanisms of innate immunity include physical barriers such as skin, chemicals barriers (antimicrobial peptides, lysozyme) and the innate leukocytes, which include the phagocytes (macrophages, neutrophils, and dendritic cells), mast cells, eosinophils, basophils, and natural killer cells2. These cells identify and eliminate pathogens, either by attacking them through contact or via phagocytosis, which includes pathogen engulfing and killing. This system does not allow lifelong defense, in contrast to adaptive immunity, which confer immunological memory against pathogens. The adaptive immune system is the second line of defense and is able to recognize and react to specific antigens of multiple microbial and non-microbial substances3. The main components of the adaptive immune system are the lymphocytes, which include B and T cells. B cells are involved in the humoral response, secreting antibodies against pathogens or exogenous proteins. However, T cells represent the cell-mediated immunity, modulating the immune response with cytokines secretion or killing pathogen-infected cells4.
Antigen presenting cells (APCs) including dendritic cells or macrophages, constituents of the innate immune system, can recognize phagocytose pathogens and process bacterial components into antigens, which are presented at the cell surface by the Major Histocompatibility Complex (MHC)5-7. After APCs have phagocytized pathogens, they usually migrate to the draining lymph nodes, where they interact with T cells. T lymphocytes can recognize specific peptide-MHC complexes by their T cell receptors. The immune synapse (IS) occurs in the interface between an antigen-loaded APC and a lymphocyte during antigen presentation8,9. Some bacteria can survive phagocytosis and disseminate systematically within APCs. In this view, infected APCs serve as bacterial reservoirs or &#34;Trojan horses&#34; that facilitate bacterial spread10. The intimate contact between APCs and lymphocytes that take place during the course of IS formation also function as a platform for exchange of part of membranes, genetic material and exosomes and can be hijacked for some viruses to infect T cells; this process is called transinfection11-13.
Some pathogenic bacteria (Listeria monocytogenes, Salmonella enterica and Shigella flexneri) are able to invade T lymphocytes in vivo and modify their behaviour14-16 . We have recently described that T lymphocytes are also able to capture bacteria by transinfection from previously infected dendritic cells (DCs) during the course of antigen presentation16. T cell bacterial capture by transinfection exceedingly more effective (1,000-4,000x) than direct infections. T cells capture pathogen and non-pathogen bacteria indicating than transinfection is a process driven by T cells. Strikingly, transinfected T (tiT) cells rapidly killed the captured bacteria and did so more efficiently than professional phagocytes16. These results, which break a dogma of immunology, show that the cells of adaptive immunity can perform functions that were supposedly exclusive of the innate immunity. In addition, we showed that tiT cells secrete large amounts of pro-inflammatory cytokines and protect from bacterial infections in vivo.
Here we present the different protocols used to study the bacterial transinfection process in a mouse model. This model is based on the use of CD4+ T cells from transgenic OTII mice, which bear a TCR specific for peptide 323-339 of OVA (OVAp) in the context of I-Ab17 that interact specifically with bacterial-infected bone marrow-derived DCs (BMDCs)18,19 loaded with OVAp, forming stable immune synapses.
T cell transinfection can be visualized and tracked using fluorescence microscopy. Additionally, flow cytometry can be used for detecting infected cells by taking advantage of the fluorescence emitted by bacteria expressing green fluorescent protein (GFP)16,20. Moreover, T cell transinfection can be quantified by a more sensitive approach, the gentamicin survival assay that allows measurement of a large number of events. Gentamicin is an antibiotic that cannot penetrate eukaryotic cells. Therefore, using this antibiotic allows differentiation of intracellular bacteria that survived the antibiotic addition from extracellular ones that were killed21.

<table border="0" cellpadding="0" cellspacing="0" width="743">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">RPMI</td>
			<td style="width:131px;">Fisher Scientific</td>
			<td style="width:104px;">SH3025501</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">r-GMCSF</td>
			<td style="width:131px;">Peprotech</td>
			<td style="width:104px;">315-03</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">LPS</td>
			<td style="width:131px;">SIGMA</td>
			<td style="width:104px;">L2630-10mg</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Na Pyruvate</td>
			<td style="width:131px;">Thermo Scientific</td>
			<td style="width:104px;">SH3023901</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">2-ME</td>
			<td style="width:131px;">Gibco</td>
			<td style="width:104px;">31350-010</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">OVAp OTII (323&#8211;339)</td>
			<td style="width:131px;">GenScript</td>
			<td style="width:104px;">---</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Cell Strainer 70uM</td>
			<td style="width:131px;">BD</td>
			<td align="right" style="width:104px;">352350</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">&#160;30uM Syringe Filcons Sterile</td>
			<td>BD</td>
			<td align="right">340598</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">AutoMacs Classic</td>
			<td style="width:131px;">Miltenyi Biotec</td>
			<td style="width:104px;">130-088-887</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Gentamicin</td>
			<td style="width:131px;">Normon</td>
			<td style="width:104px;">624601.6</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Transwell</td>
			<td style="width:131px;">Costar</td>
			<td align="right" style="width:104px;">3415</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">LB</td>
			<td style="width:131px;">Pronadisa</td>
			<td align="right">1231</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Agar</td>
			<td style="width:131px;">Pronadisa</td>
			<td align="right">1800</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:341px;">Paraformaldehyde 16%</td>
			<td style="width:131px;">Electron Microscopy Sciences</td>
			<td align="right" style="width:104px;">15710</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Triton X-100</td>
			<td style="width:131px;"></td>
			<td style="width:104px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">CD8 biot</td>
			<td style="width:131px;">BD Biosciences</td>
			<td align="right" style="width:104px;">553029</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">IgM Biot</td>
			<td style="width:131px;">ImmunoStep</td>
			<td style="width:104px;">Clone RMM-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">B220 Biot</td>
			<td style="width:131px;">BD Biosciences</td>
			<td align="right" style="width:104px;">553086</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">CD19 biot</td>
			<td style="width:131px;">BD Biosciences</td>
			<td align="right">553784</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">MHC-II Biot (I-A/I-E)</td>
			<td style="width:131px;">BD Biosciences</td>
			<td align="right">553622</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">CD11b biot</td>
			<td style="width:131px;">Immunostep</td>
			<td style="width:104px;">11BB-01mg</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">CD11c biot</td>
			<td style="width:131px;">Immunostep</td>
			<td>11CB3-01mg</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">DX5 biot</td>
			<td style="width:131px;">BD Biosciences</td>
			<td align="right" style="width:104px;">553856</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Gr-1 biot</td>
			<td style="width:131px;">BD Biosciences</td>
			<td align="right" style="width:104px;">553125</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">CD16/CD32</td>
			<td style="width:131px;">ImmunoStep</td>
			<td>M16PU-05MG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">anti Salmonella</td>
			<td style="width:131px;">ABD Serotec</td>
			<td style="width:104px;">8209-4006</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">CD11cPE</td>
			<td style="width:131px;">BD Biosciences</td>
			<td align="right" style="width:104px;">553802</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">CD4-APC</td>
			<td style="width:131px;">Tonbo Biosciences</td>
			<td style="width:104px;">20-0041-U100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Gr-1 APC</td>
			<td style="width:131px;">BD Biosciences</td>
			<td align="right">553129</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MHC-II (I-A/I-E) FITC</td>
			<td style="width:131px;">BD Biosciences</td>
			<td align="right">553623</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Alexa-Fluor 647 Goat Anti-Rabbit IgG (H+L) Antibody, highly cross-adsorbed</td>
			<td>Invitrogen</td>
			<td>A-21245</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">CMAC (7-amino-4-chloromethylcoumarin)</td>
			<td style="width:131px;">Life technologies</td>
			<td>C2110</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">BSA</td>
			<td style="width:131px;">SIGMA</td>
			<td style="width:104px;">A7030-100G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">Streptavidin MicroBeads</td>
			<td style="width:131px;">Miltenyi Biotec</td>
			<td style="width:104px;">130-048-101</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:341px;">BD FACSCanto II</td>
			<td style="width:131px;">BD Biosciences</td>
			<td style="width:104px;">---</td>
			<td></td>
		</tr>
	</tbody>
</table>

t cells capture bacteria by transinfection from dendritic cells

Recently, we have shown, contrary to what is described, that CD4+ T cells, the paradigm of adaptive immune cells, capture bacteria from infected dendritic cells (DCs) by a process called transinfection. Here, we describe the analysis of the transinfection process, which occurs during the course of antigen presentation. This process was unveiled by using CD4+ T cells from transgenic OTII mice, which bear a T cell receptor (TCR) specific for a peptide of ovoalbumin (OVAp), which therefore can form stable immune complexes with infected dendritic cells loaded with this specific OVAp. The dynamics of green fluorescent protein (GFP)-expressing bacteria during DC-T cell transmission can be monitored by live-cell imaging and the quantification of bacterial transinfection can be performed by flow cytometry. In addition, transinfection can be quantified by a more sensitive method based in the use of gentamicin, a non-permeable aminoglycoside antibiotic killing extracellular bacteria but not intracellular ones. This classical method has been used previously in microbiology to study the efficiency of bacterial infections. We hereby explain the protocol of the complete process, from the isolation of the primary cells to the quantification of transinfection.

Herein we described how to perform murine T cell bacterial transinfection from infected bone marrow derived-DCs and how to measure bacterial transinfection via two different approaches: flow cytometry and gentamicin survival assay. Figure 1 summarizes the procedure to obtain the cells. DCs are generated by incubation of bone marrow cells with GM-CSF for 9 days. Then, DCs are maturated with LPS to increase MHCII on its membrane to load them later on with a specific peptide...

Watch this Scientific Journal Video about T Cells Capture Bacteria by Transinfection from Dendritic Cells at JoVE.com

T Cells Capture Bacteria by Transinfection from Dendritic Cells

Here a protocol is presented to measure bacterial capture by CD4+ T cells which occurs during antigen presentation via transinfection from pre-infected dendritic cells (DC). We show how to perform the necessary steps: isolation of primary cells, infection of DC, DC/T cell conjugate formation, and measurement of bacterial T cell transfection.

Recently, we have shown, contrary to what is described, that CD4+ T cells, the paradigm of adaptive immune cells, capture bacteria from infected dendritic ...

The overall goal of this procedure is to quantify bacterial CD4+T cell transinfection, using a mouse cell model. In vivo, some pathogenic bacteria such as Listeria monocytogenes and Salmonella enteritidis are able to infect T lymphocytes and modify their behavior. However, in vitro, T cells are not easy to infect.Based on this observation, we investigated whether T cells can capture bacteria from infected dendritic cells during antigen presentation as occurs in viral infections. We found that T cells capture bacteria and then kill them. Actually, we found that T cells do this more efficiently than professional phagocytes.These results contradict a central tenet of immunology, showing that cells from adaptive immunity can perform functions supposedly exclusive to innate immunity. Today we present the protocol used to study the bacteria transinfection process in a mouse model. Esteban Veiga and I will be demonstrating this procedure along with Guillermo Ramirez-Santiago, Raquelle Garcia-Ferreras, two graduate students, and Monica Torres-Torresano, a technician.Note that all the procedures described in this video should be carried out in the hood, using only sterile media, instruments, pipette tips, and culture dishes. In a non-tissue culture treated sterile 15 centimeter Petri dish, add one microliter of one milligram per milliliter lipopolysaccharide to the bone marrow derived dendritic cells from a single mouse. Incubate the cells for 24 hours to increase major histocompatibility complex II, or MHC II, expression.Following the incubation, perform flow cytometry to confirm MHC II expression and differentiation. After MHC II expression has been confirmed, as shown here, transfer the cells to a sterile 50 milliliter polypropylene tube. Add 10 milliliters of PBS containing five millimolar EDTA, then centrifuge the cells at 600 x g.Once the spin is complete, perform a wash by resuspending the cells in RPMI with 10%FBS, then centrifuging again. Then, after the wash, add one milliliter of RPMI 10%FBS for every five times 10 to the sixth dendritic cells, and pipette up and down to resuspend them. Next, separate the resuspended dendritic cells into two tubes of equal volume.To one tube, add 10 micrograms per milliliter OT-II OVAp. Leave the other tube untreated. It will serve as a negative control for antigen loading.Incubate the tubes for at least one hour to load the MHC II molecules of dendritic cells with OVA peptide. Meanwhile, prepare the Salmonella enteritidis for infection by washing them with a PBS solution three times. Centrifuge between each wash at 1800 x g to eliminate the LB medium and any secreted toxins.Then, resuspend the bacteria in RPMI. Following the incubation, infect each tube of dendritic cells at a multiplicity of infection, or MOI, of 10, and then incubate the cells for one hour. Once the cells have been infected, wash them three times with PBS, and then once with RPMI 10%FBS.Centrifuge between washes at 450 x g to wash away most of the extracellular bacteria in the soluble OVAp. After the last centrifugation, resuspend the cells in RPMI 10%FBS at 20 times 10 to the sixth cells per milliliter. To a 24-well culture plate, add two million CD4+T cells in a volume of 0.5 milliliters to each of five wells.Next, to control for physical contact, place polycarbonate trans-well barriers with a three micrometer pore size into the third and fourth wells. To the first well, add 0.1 milliliters of the infected overloaded dendritic cells. To the second well, add 0.1 milliliters of the infected non-loaded dendritic cells.Add 0.1 milliliters of the infected overloaded dendritic cells to one well, and 0.1 milliliters of the infected non-loaded dendritic cells into the other well. Finally, as a negative control, directly infect the fifth well of CD4+T cells at an MOI of 10. Then, bring the total volume of the well up to 0.6 milliliters with RPMI.Incubate the plate for 30 minutes to allow immune synapses to form. After the incubation, add 100 micrograms of Gentamicin per milliliter of medium to each well, and incubate for one hour. Gentamicin is an aminoglycoside antibiotic that is not able to penetrate eukaryotic cells.Therefore, in this step, aminoglycoside will kill extracellular bacteria but not intracellular bacteria. Following the incubation, collect the non-adherent cells in 15 milliliter tubes, and resuspend them in 10 milliliters of PBS BSA EDTA buffer. Discard the plastic culture plate to which most of the dendritic cells remain attached.Next, vortex the tubes gently to ensure cell desegregation. Centrifuge the tubes at 600 x g. Then, from any tube, aspirate 500 microliters of the cell supernatant and pipette it into a new tube.This will be used as a control to show that the Gentamicin treatment was effective. Place all of the samples on ice. At this stage, there are six tubes:four tubes of test samples and two controls.Although most of the dendritic cells were discarded with the plate, the samples that were not separated by the trans-well barriers could still contain some. To reduce contamination, use magnetic cell isolation or cell sorting to re-isolate the CD4+T cells from the samples that were not separated by trans-well barriers. The final isolate should contain less than 2%dendritic cells.Keep the rest of the samples on ice. Once the CD4+T cells have been purified, it is time to save for bacteria class infection. This can be done by performing colony counts, or by flow cytometry.Here, we will show you how to perform colony counts. Wash the transinfected CD4+T cells twice with PBS. Centrifuge at 600 x g between washes.Then count the cells and resuspend them in PBS at a concentration of two times 10 to the sixth cells per milliliter. To 500 microliters of T cells, add 500 microliters of 0.1%Triton X-100 to lyse them. This releases the intracellular bacteria from the T cells.For each sample of lysed cells, make three serial dilutions. Then, divide an LB agar plate into quarters and spread 50 microliters of each dilution, including the undiluted suspension, onto each section of the plate. On a separate LB agar plate, spread the stored cell supernatant as a control for Gentamicin efficacy.Then, on another plate, spread the directly infected T cells as an additional control. Incubate overnight. The next day, count the colonies in each section of the plate and calculate the number of colony-forming units for each sample.If low-level dendritic cell contamination occurs, which is defined as less than 2%subtract the colony-forming units corresponding to low dendritic cell contamination. T cell transinfection was performed using Salmonella enteritidis and quantified by Gentamicin survival assay as described in this video. When directly infected T cells were plated, as shown on the left, growth of colonies was not observed, indicated that T cells are refractory to direct bacterial infections.When supernatant from transinfection assays was plated, as shown on the right, colonies were not observed, indicating that the Gentamicin worked properly. Results from transinfection assays performed in the presence of trans-well barriers are shown here. Only three colonies are observed in the undiluted suspension from both OVA-loaded and non-loaded samples.In contrast, numerous colonies are seen when there is direct contact of T cells with infected dendritic cells. Moreover, when dendritic cells loaded with OVAp were incubated with T cells, the uptake of bacteria was increased by about five times. Taken together, these data indicate that direct contact of infected dendritic cells with T cells facilitates bacterial uptake and that cell transinfection is enhanced during antigen recognition.After this video, you should have a good understanding of how to quantify transinfection using marine T cells. The advantage of quantifying transinfection with the Gentamicin survival is its great sensitivity. We are able to detect one single infecting bacterium.Is it is important to remember that the purification step of this procedure is critical. The purity must be very high if colony counts will be used to determine the transinfection rate. Quantification by flow cytometry does not have this limitation, because you can easily distinguish dendritic cells and T cells, but the restriction is that the GFP expressing bacteria must be bright enough to detect the infected cells against the outer fluorescence background.Don't forget that working with pathogens can be extremely hazardous and the appropriate safety precautions should always be used when performing this procedure.

t-cells-capture-bacteria-by-transinfection-from-dendritic-cells

Research

JoVE Journal

Immunology and Infection

Following Cell-fate in E. coli After Infection by Phage Lambda

The system comprising bacteriophage (phage) lambda and the bacterium E. coli has long served as a paradigm for cell-fate determination1,2. Following the simultaneous infection of the cell by a number of phages, one of two pathways is chosen: lytic (virulent) or lysogenic (dormant)3,4. We recently developed a method for fluorescently labeling individual phages, and were able to examine the post-infection decision in real-time under the microscope, at the level of individual phages and cells5. Here, we describe the full procedure for performing the infection experiments described in our earlier work5. This includes the creation of fluorescent phages, infection of the cells, imaging under the microscope and data analysis. The fluorescent phage is a "hybrid", co-expressing wild- type and YFP-fusion versions of the capsid gpD protein. A crude phage lysate is first obtained by inducing a lysogen of the gpD-EYFP (Enhanced Yellow Fluorescent Protein) phage, harboring a plasmid expressing wild type gpD. A series of purification steps are then performed, followed by DAPI-labeling and imaging under the microscope. This is done in order to verify the uniformity, DNA packaging efficiency, fluorescence signal and structural stability of the phage stock. The initial adsorption of phages to bacteria is performed on ice, then followed by a short incubation at 35&deg;C to trigger viral DNA injection6. The phage/bacteria mixture is then moved to the surface of a thin nutrient agar slab, covered with a coverslip and imaged under an epifluorescence microscope. The post-infection process is followed for 4 hr, at 10 min interval. Multiple stage positions are tracked such that ~100 cell infections can be traced in a single experiment. At each position and time point, images are acquired in the phase-contrast and red and green fluorescent channels. The phase-contrast image is used later for automated cell recognition while the fluorescent channels are used to characterize the infection outcome: production of new fluorescent phages (green) followed by cell lysis, or expression of lysogeny factors (red) followed by resumed cell growth and division. The acquired time-lapse movies are processed using a combination of manual and automated methods. Data analysis results in the identification of infection parameters for each infection event (e.g. number and positions of infecting phages) as well as infection outcome (lysis/lysogeny). Additional parameters can be extracted if desired.

Following Cell-fate in E. coli After Infection by Phage Lambda

This article describes the procedure for preparing a fluorescently-labeled version of bacteriophage lambda, infection of E. coli bacteria, following the infection outcome under the microscope, and analysis of infection results.

The system comprising bacteriophage (phage) lambda and the bacterium E. coli has long served as a paradigm for cell-fate determination1,2. Following the ...

Isolation of Mouse Lung Dendritic Cells

Lung dendritic cells (DC) play a fundamental role in sensing invading pathogens 1,2 as well as in the control of tolerogenic responses 3 in the respiratory tract. At least three main subsets of lung dendritic cells have been described in mice: conventional DC (cDC) 4, plasmacytoid DC (pDC) 5 and the IFN-producing killer DC (IKDC) 6,7. The cDC subset is the most prominent DC subset in the lung 8. 
The common marker known to identify DC subsets is CD11c, a type I transmembrane integrin (&beta;2) that is also expressed on monocytes, macrophages, neutrophils and some B cells 9. In some tissues, using CD11c as a marker to identify mouse DC is valid, as in spleen, where most CD11c+ cells represent the cDC subset which expresses high levels of the major histocompatibility complex class II (MHC-II). However, the lung is a more heterogeneous tissue where beside DC subsets, there is a high percentage of a distinct cell population that expresses high levels of CD11c bout low levels of MHC-II. Based on its characterization and mostly on its expression of F4&#47;80, an splenic macrophage marker, the CD11chiMHC-IIlo lung cell population has been identified as pulmonary macrophages 10 and more recently, as a potential DC precursor 11. 
In contrast to mouse pDC, the study of the specific role of cDC in the pulmonary immune response has been limited due to the lack of a specific marker that could help in the isolation of these cells. Therefore, in this work, we describe a procedure to isolate highly purified mouse lung cDC. The isolation of pulmonary DC subsets represents a very useful tool to gain insights into the function of these cells in response to respiratory pathogens as well as environmental factors that can trigger the host immune response in the lung.

A highly purified preparation of mouse lung dendritic cells is described. Specific emphasis is given to the isolation of conventional dendritic cell subset.

Lung dendritic cells (DC) play a fundamental role in sensing invading pathogens 1,2 as well as in the control of tolerogenic responses 3 in the ...

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 ...

Isolation and Characterization of Dendritic Cells and Macrophages from the Mouse Intestine

Within the intestine reside unique populations of innate and adaptive immune cells that are involved in promoting tolerance towards commensal flora and food antigens while concomitantly remaining poised to mount inflammatory responses toward invasive pathogens1,2. Antigen presenting cells, particularly DCs and macrophages, play critical roles in maintaining intestinal immune homeostasis via their ability to sense and appropriately respond to the microbiota3-14. Efficient isolation of intestinal DCs and macrophages is a critical step in characterizing the phenotype and function of these cells. While many effective methods of isolating intestinal immune cells, including DCs and macrophages, have been described6,10,15-24, many rely upon long digestions times that may negatively influence cell surface antigen expression, cell viability, and/or cell yield. Here, we detail a methodology for the rapid isolation of large numbers of viable, intestinal DCs and macrophages. Phenotypic characterization of intestinal DCs and macrophages is carried out by directly staining isolated intestinal cells with specific fluorescence-labeled monoclonal antibodies for multi-color flow cytometric analysis. Furthermore, highly pure DC and macrophage populations are isolated for functional studies utilizing CD11c and CD11b magnetic-activated cell sorting beads followed by cell sorting.

Here, we detail a methodology for the rapid isolation of mouse intestinal dendritic cells (DCs) and macrophages. Phenotypic characterization of intestinal DCs and macrophages is performed using multi-color flow cytometric analysis while magnetic bead enrichment followed by cell sorting is used to yield highly pure populations for functional studies.

Within the intestine reside unique populations of innate and adaptive immune cells that are involved in promoting tolerance towards commensal flora and ...

Isolating And Immunostaining Lymphocytes and Dendritic Cells from Murine Peyer's Patches

Peyer's patches (PPs) are integral components of the gut-associated lymphoid tissues (GALT) and play a central role in intestinal immunosurveillance and homeostasis. Particulate antigens and microbes in the intestinal lumen are continuously sampled by PP M cells in the follicle-associated epithelium (FAE) and transported to an underlying network of dendritic cells (DCs), macrophages, and lymphocytes. In this article, we describe protocols in which murine PPs are (i) dissociated into single cell suspensions and subjected to flow cytometry and (ii) prepared for cryosectioning and immunostaining. For flow cytometry, PPs are mechanically dissociated and then filtered through 70 &mu;m membranes to generate single cell suspensions free of epithelial cells and large debris. Starting with 20-25 PPs (from four mice), this quick and reproducible method yields a population of &gt;2.5 x 106 cells with &gt;90% cell viability. For cryosectioning, freshly isolated PPs are immersed in Optimal Cutting Temperature (OCT) medium, snap-frozen in liquid nitrogen, and then sectioned using a cryomicrotome. Tissue sections (5-12 &mu;m) are air-dried, fixed with acetone or methanol, and then subjected to immunolabeling.

Isolating And Immunostaining Lymphocytes and Dendritic Cells from Murine Peyer&#039;s Patches

There is an increasing interest in understanding the immunological functions of specific subpopulations of cells in Peyer's patches (PPs), the primary inductive sites of gut-associated lymphoid tissues. Here we outline parallel protocols for preparing PP single cell preparations for flow cytometric analysis and PP cryosections for immunostaining.

Peyer's  patches (PPs) are integral components of the gut-associated lymphoid tissues  (GALT) and play a central role in intestinal immunosurveillance and ...

Isolation of Myeloid Dendritic Cells and Epithelial Cells from Human Thymus

In this protocol we provide a method to isolate dendritic cells (DC) and epithelial cells (TEC) from the human thymus. DC and TEC are the major antigen presenting cell (APC) types found in a normal thymus and it is well established that they play distinct roles during thymic selection. These cells are localized in distinct microenvironments in the thymus and each APC type makes up only a minor population of cells. To further understand the biology of these cell types, characterization of these cell populations is highly desirable but due to their low frequency, isolation of any of these cell types requires an efficient and reproducible procedure. This protocol details a method to obtain cells suitable for characterization of diverse cellular properties. Thymic tissue is mechanically disrupted and after different steps of enzymatic digestion, the resulting cell suspension is enriched using a Percoll density centrifugation step. For isolation of myeloid DC (CD11c+), cells from the low-density fraction (LDF) are immunoselected by magnetic cell sorting. Enrichment of TEC populations (mTEC, cTEC) is achieved by depletion of hematopoietic (CD45hi) cells from the low-density Percoll cell fraction allowing their subsequent isolation via fluorescence activated cell sorting (FACS) using specific cell markers. The isolated cells can be used for different downstream applications.

This protocol details a method to isolate antigen presenting cells from human thymus via different steps of enzymatic digestion of the tissue followed by density centrifugation of the single cell suspension and finally magnetic and/or FACS sorting of the cell populations of interest.

In this protocol we provide a method to isolate dendritic cells (DC) and epithelial cells (TEC) from the human thymus. DC and TEC are the major antigen ...

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 ...

Derivation of T Cells In Vitro from Mouse Embryonic Stem Cells

The OP9/OP9-DL1 co-culture system has become a well-established method for deriving differentiated blood cell types from embryonic and hematopoietic progenitors of both mouse and human origin. It is now used to address a growing variety of complex genetic, cellular and molecular questions related to hematopoiesis, and is at the cutting edge of efforts to translate these basic findings to therapeutic applications. The procedures are straightforward and routinely yield robust results. However, achieving successful hematopoietic differentiation in vitro requires special attention to the details of reagent and cell culture maintenance. Furthermore, the protocol features technique sensitive steps that, while not difficult, take care and practice to master. Here we focus on the procedures for differentiation of T lymphocytes from mouse embryonic stem cells (mESC). We provide a detailed protocol with discussions of the critical steps and parameters that enable reproducibly robust cellular differentiation in vitro. It is in the interest of the field to consider wider adoption of this technology, as it has the potential to reduce animal use, lower the cost and shorten the timelines of both basic and translational experimentation.

Derivation of T Cells In Vitro from Mouse Embryonic Stem Cells

Mouse embryonic stem cells can be differentiated to T cells in vitro using the OP9-DL1 co-culture system. Success in this procedure requires careful attention to reagent/cell maintenance, and key technique sensitive steps. Here we discuss these critical parameters and provide a detailed protocol to encourage adoption of this technology.

The OP9/OP9-DL1 co-culture system has become a well-established method for deriving differentiated blood cell types from embryonic and hematopoietic ...

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 ...

Automated Cell Enrichment of Cytomegalovirus-specific T cells for Clinical Applications using the Cytokine-capture System

The adoptive transfer of pathogen-specific T cells can be used to prevent and treat opportunistic infections such as cytomegalovirus (CMV) infection occurring after allogeneic hematopoietic stem-cell transplantation. Viral-specific T cells from allogeneic donors, including third party donors, can be propagated ex vivo in compliance with current good manufacturing practice (cGMP), employing repeated rounds of antigen-driven stimulation to selectively propagate desired T cells. The identification and isolation of antigen-specific T cells can also be undertaken based upon the cytokine capture system of T cells that have been activated to secrete gamma-interferon (IFN-&#947;). However, widespread human application of the cytokine capture system (CCS) to help restore immunity has been limited as the production process is time-consuming and requires a skilled operator. The development of a second-generation cell enrichment device such as CliniMACS Prodigy now enables investigators to generate viral-specific T cells using an automated, less labor-intensive system. This device separates magnetically labeled cells from unlabeled cells using magnetic activated cell sorting technology to generate clinical-grade products, is engineered as a closed system and can be accessed and operated on the benchtop. We demonstrate the operation of this new automated cell enrichment device to manufacture CMV pp65-specific T cells obtained from a steady-state apheresis product obtained from a CMV seropositive donor. These isolated T cells can then be directly infused into a patient under institutional and federal regulatory supervision. All the bio-processing steps including removal of red blood cells, stimulation of T cells, separation of antigen-specific T cells, purification, and washing are fully automated. Devices such as this raise the possibility that T cells for human application can be manufactured outside of dedicated good manufacturing practice (GMP) facilities and instead be produced in blood banking facilities where staff can supervise automated protocols to produce multiple products.

The goal of this protocol is to manufacture pathogen-specific clinical-grade T cells using a bench-top, automated, second generation cell enrichment device that incorporates a closed cytokine capture system and does not require dedicated staff or use of a GMP facility. The cytomegalovirus pp65-specific-T cells generated can be directly administered to patients.

The adoptive transfer of pathogen-specific T cells can be used to prevent and treat opportunistic infections such as cytomegalovirus (CMV) infection ...