D.E. and M.B.D. are members of a multidisciplinary research platform (MRP) of Ghent University, and the Ghent Researchers on Unfolded Proteins in Inflammatory Disease (GROUP-ID) consortium.

In this study, adult (6-8 weeks) female C57Bl/6 mice were used. Mice were housed and bred according to the guidelines of the Ghent University vivarium. All animal procedures were approved by the Institutional Animal Care and Ethics Committee.
1. Preparation of Mononuclear Cells (MNCs) from Mouse Spleen
<ol>
	<li>Sacrifice the mouse by cervical dislocation.</li>
	<li>Place the mouse back down on the dissecting board and fix the hind and forelegs with pins.</li>
	<li>Sterilize the skin-surface with 70% (vol/vol) ethanol/H2O.</li>
	<li>Cut the skin along the abdominal midline to the thorax and expose the spleen using sterile surgical instruments.</li>
	<li>After trimming the surrounding fat tissues, place the spleen into a 24 well plate containing 1 ml 1x phosphate buffered saline (PBS) at RT.</li>
	<li>Dissect the spleen using a sterile scalpel and transfer the pieces into a 70 &#181;m nylon filter placed within a 50 ml tube.</li>
	<li>Using a 2 ml syringe plunger, gently mash the spleen pieces through the cell strainer and wash with 5 ml 1x PBS.</li>
	<li>Add 3 ml of Ficoll-Paque to a 15 ml tube and overlay the density gradient medium with the 5 ml cellular suspension.</li>
	<li>Centrifuge at 400 x g for 20 min at RT without brake.</li>
	<li>Transfer the interphase to a fresh 15 ml tube, add 10 ml cold 1x PBS and centrifuge at 300 x g for 10 min at 4 &#176;C.</li>
	<li>Resuspend the cells in 2 ml 1x PBS containing 0.5% bovine serum albumin (BSA) and 1 mM ethylenediaminetetraacetic acid (EDTA) (FACS buffer). Transfer 10 &#181;l of the cell suspension to a small tube, mix with 10 &#181;l of&#160;0.4%</li>
</ol>
2. Enrichment, Detection and Purification of Mouse iNKT Cells
<ol>
	<li>Enrichment of mouse splenic CD5positive (CD5+) lymphocytes.
	<ol>
		<li>(Optional) Stain 105 cells with FITC-conjugated anti-CD5 (4 &#181;l of 1:30 dilution/106 cells) for 30 min at 4 &#176;C in the dark, wash with 200 &#181;l FACS buffer and resuspend in 500 &#181;l FACS buffer. Prepare a 20 &#181;M working solution of 4&#39;,6-diamidino-2-phenylindole (DAPI) in 1x PBS, add 1 &#181;l thereof to 105 cells in FACS buffer and incubate at RT for 5 min. Acquire 104 pre-enriched cells on the flow cytometer.
		<ol>
			<li>Using FCS-H and FCS-W, electronically gate on FSC-Wlo cells to exclude cell doublets and aggregates (Figure 1A). Then electronically gate out DAPI+ (dead) cells within the FSC-Wlo population (Figure 1B), and use SSC-A and FCS-A to electronically select the lymphocyte population by size (Figure 1C).</li>
			<li>Using cells within the lymphocyte gate, plot SSC-A versus CD5 and electronically gate CD5+ lymphocytes as shown in Figure 1D. Acquire the remainder of the pre-enriched sample on the flow cytometer.</li>
		</ol>
		</li>
		<li>Adjust cell counts to 107 cells per 90 &#181;l in FACS buffer and add 10 &#181;l anti-CD5 microbeads.</li>
		<li>Incubate at 4 &#186;C for 15 min, wash once with 4 ml FACS buffer and resuspend in 500 &#181;l cold FACS buffer. Enrich for CD5+ lymphocytes using magnetic cell separation (MACS)columns according to manufacturer&#8217;s recommendations.</li>
		<li>Optional) Stain 105 cells with FITC-conjugated anti-CD5 (4 &#181;l of 1:30 dilution/106 cells) and DAPI as in 2.1.1. Acquire 104 enriched lymphocytes on the flow cytometer and verify that the electronic gates created in 2.1.1. select CD5+ lymphocytes in the enriched cellular fraction. Acquire 105 cells on the flow cytometer and analyze the percentage CD5+ lymphocytes present in the enriched fraction as shown in Figure 1E-H.</li>
	</ol>
	</li>
	<li>Detection and isolation of mouse iNKT cells by FACS.
	<ol>
		<li>Resuspend enriched CD5+ lymphocytes at a concentration of approximately 106 cells per 20 &#181;l in FACS buffer containing anti-CD16/CD32 (4 &#181;l of 1:50 dilution/106 cells) and PE-conjugated &#945;GalCer/CD1d tetramer (1 &#181;g/106 cells).</li>
		<li>Incubate for 30 min at RT in the dark.</li>
		<li>Dilute mouse antibodies (mAbs) anti-CD3&#949; V500 (4 &#181;l of 1:20 dilution/106 cells), anti-CD19 e450 (4 &#181;l of 1:50 dilution/106 cells) and anti-CD8&#945; e450 (4 &#181;l of 1:50 dilution/106 cells) in FACS buffer, add to CD5+ lymphocytes and incubate for 30 min at 4 &#176;C in the dark.</li>
		<li>Wash the cells with 1 ml FACS buffer by centrifuging at 300 x g for 10 min at 4 &#176;C and resuspend in 4 ml FACS buffer at a final concentration of 107 cells/ml.</li>
		<li>Filter the cells through a 30 &#181;m cell strainer and place the cells on ice.</li>
		<li>Calibrate the flow cytometer for cell sorting according to the manufacturer&#8217;s recommendations 14,15. 
		Note: Calibration of a flow cytometer for cell sorting requires training and can be performed by an experienced operator, or a trained technician.</li>
		<li>Add 10 &#181;l of a 20 &#181;M working solution of DAPI per 106 cells and incubate at RT for 5 min. Acquire approximately 104 enriched CD5+ lymphocytes on the flow cytometer. Electronically gate on FSC-Wlo cells to exclude cell doublets and aggregates (Figure 2A). Then electronically gate out DAPI+ CD8+CD19+ cells (dump channel) within the FSC-Wlo population (Figure 2B), and use SSC-A and FCS-A to electronically select lymphocytes (Figure 2C) as described in 2.1.1.1.
		<ol>
			<li>Plot &#945;GalCer/CD1d tetramer by CD3&#949; and electronically gate &#945;GalCer/CD1d tetramer+CD3&#949;+ iNKT cells as shown in&#160; Figure 2D. Acquire no more than 2 x 105 CD5+ enriched lymphocytes to determine the percentage &#945;GalCer/CD1d tetramer+CD3&#949;+ iNKT cells present in the enriched cellular fraction.</li>
		</ol>
		</li>
		<li>Using the electronic gates created in 2.2.7., FACS sort &#945;GalCer/CD1d tetramer+CD3&#949;+ iNKT cells on the flow cytometer at 70 psi using a 70 &#181;m nozzle at a flow rate of &#39;1.5&#39;. Collect sorted iNKT cells in a FACS tube containing 1 ml 100% FCS. Subsequently rinse sorted iNKT cells from the side of the FACS tube using 10 ml RMPI 1640 medium and centrifuge the cells at 300 x g for 10 min at 4 &#176;C.</li>
		<li>Resuspend sorted iNKT cells in 1 ml RPMI 1640 medium and acquire 40 &#181;l thereof on a flow cytometer to assess the purity of sorted iNKT cells. Select FSC-Wlo DAPI- lymphocytes as described in 2.2.7. (Figure 2E-G) and electronically gate &#945;GalCer/CD1d tetramer+CD3&#949;+ iNKT cells as shown in Figure 2H.</li>
	</ol>
	</li>
</ol>
3. Culture and Expansion of Mouse iNKT Cells
Day 0
<ol>
	<li>Coat a flat-bottomed 96 well plate with purified anti-CD3&#949; (3 &#181;g/ml) per well for 1 hr at RT. Wash twice with 200 &#181;l 1x PBS and once with 200 &#181;l complete RPMI 1640 medium (10% vol/vol FCS, 100 U/ml penicillin&#8211;streptomycin, 5.5 &#181;M &#946;-mercaptoethanol).</li>
	<li>Count the number of viable sorted iNKT cells (step 2.2.8)&#160;using 0.4% a hemocytometer as in 1.11., centrifuge at 300 x g for 10 min at 4 &#176;C and resuspend at 5 x 105 cells/ml in complete RPMI 1640 medium containing recombinant murine IL-2 (10 ng/ml), recombinant murine IL-12 (1 ng/ml) and soluble anti-mouse CD28 (5 &#181;g/ml). Plate sorted iNKT cells at 105 cells/well in anti-CD3&#949; coated plates and incubate at 37 &#176;C in a CO2 incubator for 2 days.</li>
</ol>
Day 2&#160;
<ol start="3">
	<li>Transfer the cells to a fresh uncoated flat-bottomed 96 well plate and culture the cells under resting conditions in complete RPMI 1640 medium at 37 &#176;C in a CO2 incubator for 2 days.</li>
</ol>
Day 4&#160;
<ol start="4">
	<li>Dislodge the cells from the plate by gentle pipetting and transfer the cells to a fresh 15 ml tube. Centrifuge at 300 x g for 10 min at 4 &#176;C, resuspend at 5 x 105 cells/ml&#160;in complete RPMI 1640 medium containing recombinant murine IL-7 (5 ng/ml), and plate 105 cells/well in a flat-bottomed 96 well plate for 4 days at 37 &#176;C in a CO2 incubator.</li>
</ol>
Day 8
<ol start="5">
	<li>Collect the cells in a fresh tube, centrifuge at 300 x g for 10 min at 4 &#176;C and resuspend at 5 x 105 cells/ml in complete RPMI 1640 medium containing soluble anti-CD28 (5 &#181;g/ml).</li>
	<li>Coat a flat-bottomed 96 well plate with purified anti-CD3&#949; (3 &#181;g/ml) per well and wash as in 3.1. Plate 105 cells/well in anti-CD3&#949; coated plates and incubate at 37 &#176;C in a CO2 incubator until day 11.</li>
</ol>
Day 11 &#8211; 18
<ol start="7">
	<li>Repeat steps 3.4 to 3.6.</li>
</ol>
Day 19-20
<ol start="8">
	<li>Transfer the cells to a fresh 15 ml tube, centrifuge at 300 x g and resuspend at 5 x 105 cells/ml in complete RPMI 1640 medium.</li>
	<li>Plate cells at 105 cells/well in a flat-bottomed 96 well plate and allow the cells to rest for 2 days at 37 &#176;C in a CO2 incubator prior to use in an experiment.</li>
</ol>
4. Cytokine Production by Mouse iNKT Cells Using a CD1d Plate-bound Assay
<ol>
	<li>Coat a flat-bottomed 96 well plate with 100 &#181;l of recombinant murine CD1d (10 &#181;g/ml in 1x PBS) per well and incubate for 1 hr at 37 &#176;C.</li>
	<li>Wash four times with 200 &#181;l 1x PBS, add 200 &#181;l of 2% FCS in 1x PBS (blocking solution) per well and incubate for 2 hr at 37 &#176;C.</li>
	<li>Remove the blocking solution, add 200 &#181;l of &#945;GalCer (5 ng/&#181;l) per well, and incubate the plate at 37 &#176;C for 16 hr. [For preparation of the &#945;GalCer solution, add 1,085 &#181; 1x PBS to 55 &#181;g of &#945;GalCer dissolved in vehicle containing 96 mg/ml&#160;sucrose, 10 mg/ml sodium deoxycholate and 5 mg/ml tween 20].</li>
	<li>After incubation, discard the &#945;GalCer solution and wash the well twice with 200 &#181;l 1x PBS followed by 200 &#181;l complete RPMI 1640 medium.</li>
	<li>Collect the in vitro expanded iNKT cells at day 21, centrifuge the cells at 300 x g for 10 min at 4 &#176;C and resuspend in complete RPMI 1640 medium at a concentration of 0.5 x 106 cells/ml.</li>
	<li>Add 200 &#181;l of the iNKT cell resuspension per well and incubate for 72 hr at 37 &#176;C in a CO2 incubator.</li>
	<li>Collect the supernatant and measure cytokines of interest by enzyme-linked immunosorbant assay (ELISA) according to manufacturer&#8217;s protocol.</li>
</ol>

<ol>
	<li>Bendelac, A., Rivera, M. N., Park, S. H., Roark, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+CD1-specific+NK1+T+cells:+development,+specificity,+and+function.">Mouse CD1-specific NK1 T cells: development, specificity, and function.</a> Annu Rev Immunol. 15, 535-562 (1997).</li><li>Kronenberg, M., Gapin, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+unconventional+lifestyle+of+NKT+cells.">The unconventional lifestyle of NKT cells.</a> Nat Rev Immuno. 2, 557-568 (2002).</li><li>Park, S. H., 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=The+mouse+CD1d-restricted+repertoire+is+dominated+by+a+few+autoreactive+T+cell+receptor+families.">The mouse CD1d-restricted repertoire is dominated by a few autoreactive T cell receptor families.</a> J Exp Med. 193, 893-904 (2001).</li><li>Zhou, D., 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=Lysosomal+glycosphingolipid+recognition+by+NKT+cells.">Lysosomal glycosphingolipid recognition by NKT cells.</a> Science. 306, 1786-1789 (2004).</li><li>Cardell, 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=CD1-restricted+CD4++T+cells+in+major+histocompatibility+complex+class+II-deficient+mice.">CD1-restricted CD4+ T cells in major histocompatibility complex class II-deficient mice.</a> J Exp Med. 182, 993-1004 (1995).</li><li>Kawano, 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=CD1d-restricted+and+TCR-mediated+activation+of+valpha14+NKT+cells+by+glycosylceramides.">CD1d-restricted and TCR-mediated activation of valpha14 NKT cells by glycosylceramides.</a> Science. 278, 1626-1629 (1997).</li><li>Drennan, M. B., Aspeslagh, S., Elewaut, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Invariant+natural+killer+T+cells+in+rheumatic+disease:+a+joint+dilemma.">Invariant natural killer T cells in rheumatic disease: a joint dilemma.</a> Nat Rev Rheumatol. 6, 90-98 (2010).</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=NKT+cells+in+immunoregulation+of+tumor+immunity:+a+new+immunoregulatory+axis.">NKT cells in immunoregulation of tumor immunity: a new immunoregulatory axis.</a> Trends Immunol. 28, 491-496 (2007).</li><li>Molling, J. 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=Generation+and+sustained+expansion+of+mouse+spleen+invariant+NKT+cell+lines+with+preserved+cytokine+releasing+capacity.">Generation and sustained expansion of mouse spleen invariant NKT cell lines with preserved cytokine releasing capacity.</a> J Immunol Methods. 322, 70-81 (2007).</li><li>Chiba, 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=Rapid+and+reliable+generation+of+invariant+natural+killer+T-cell+lines+in+vitro.">Rapid and reliable generation of invariant natural killer T-cell lines in vitro.</a> Immunology. 128, 324-333 (2009).</li><li>Gumperz, J. 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=Murine+CD1d-restricted+T+cell+recognition+of+cellular+lipids.">Murine CD1d-restricted T cell recognition of cellular lipids.</a> Immunity. 12, 211-221 (2000).</li><li>Behar, S. M., Podrebarac, T. A., Roy, C. J., Wang, C. R., Brenner, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diverse+TCRs+recognize+murine+CD1.">Diverse TCRs recognize murine CD1.</a> J Immunol. 162, 161-167 (1999).</li><li>Watarai, H., Nakagawa, R., Omori-Miyake, M., Dashtsoodol, N., Taniguchi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+for+detection,+isolation+and+culture+of+mouse+and+human+invariant+NKT+cells.">Methods for detection, isolation and culture of mouse and human invariant NKT cells.</a> Nature protocols. 3, 70-78 (2008).</li><li>Houtz, B., Trotter, J., Sasaki, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> BD FACService TECHNOTES. 9 (4), (2004).</li><li>Osborne, G. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+of+quantifying+cell+sorting+yield+in+'real+time'.">A method of quantifying cell sorting yield in 'real time'.</a> Cytometry. Part A : the journal of the International Society for Analytical Cytology. 77, 983-989 (2010).</li><li>Drennan, M. B., 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=The+thymic+microenvironment+differentially+regulates+development+and+trafficking+of+invariant+NKT+cell+sublineages.">The thymic microenvironment differentially regulates development and trafficking of invariant NKT cell sublineages.</a> J Immunol. 193, 5960-5972 (2014).</li></ol>

The authors have no competing interests to disclose.

Critical steps in the current protocol include the isolation and subsequent enrichment of CD5+ lymphocytes (Section 1 &#38; 2), FACS sorting (Section 3) and the initial plating of iNKT cells (Section 4). Of the steps performed in Section 1, remember to carefully layer the splenic cellular suspension over the density gradient medium such that a distinct cellular interphase is generated following centrifugation. The subsequent enrichment for CD5+ lymphocytes by magnetic cell separation (Section 2) min...

Murine invariant natural killer T (iNKT) cells are a distinct population of innate T lymphocytes selected in the thymus by CD1d-expressing cortical thymocytes 1,2. iNKT cells express a T cell receptor (TCR) comprised of an invariant V&#945;14-J&#945;18 TCR chain paired with either V&#946;8, V&#946;7 or V&#946;2 TCRs 3, which is capable of recognizing endogenous as well as foreign lipid antigens in the context of CD1d. For example, murine iNKT cells recognize and are activated by an endogenous lipid antigen called isoglobotrihexosylceramide (iGb3) 4, as well as &#945;-galactosylceramide (&#945;GalCer) 5,6, a glycolipid isolated from marine sponges. TCR-dependent activation of iNKT cells promotes the priming of adaptive immune responses, and as a result, iNKT cells have been shown to be functionally involved in the amelioration or development of a range of pathologies including rheumatic disease 7 and cancer 8. Currently, synthetic iNKT cell ligands constitute promising new vaccine adjuvants that may be capable of regulating a number of immunopathological conditions.
It has previously been demonstrated that iNKT cells can be generated in vitro following isolation from mouse tissue however; many of these studies employ the use of primary antigen-presenting cells (APCs) and/or cell lines 9, V&#945;14 TCR transgenic (Tg) mice 10, or thymomas for the generation of iNKT cell-derived hybridomas 11,12. Furthermore, large numbers of mice, high volumes of reagents such as &#945;GalCer-loaded CD1d dimers, and lengthy culture times make some published protocols less ethically and economically appealing 9,13.
In this report we describe an adapted method for the isolation and in vitro expansion of iNKT cells from mouse spleen. More specifically, the protocol describes a method for enriching iNKT cells from mouse spleen which reduces the mice, reagents and time required for FACS cell sorting, and proposes an optimized approach for expanding sorted splenic iNKT cells in vitro.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Material</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>recombinant murine IL-2</td>
			<td>eBiosciences</td>
			<td>14-8021</td>
			<td></td>
		</tr>
		<tr>
			<td>recombinant murine IL-12</td>
			<td>eBiosciences</td>
			<td>39-8122-65</td>
			<td></td>
		</tr>
		<tr>
			<td>recombinant murine IL-7</td>
			<td>eBiosciences</td>
			<td>14-8071</td>
			<td></td>
		</tr>
		<tr>
			<td>purified anti-mouse CD3e (145-2C11)</td>
			<td>eBiosciences</td>
			<td>16-0032-86</td>
			<td></td>
		</tr>
		<tr>
			<td>purified anti-mouse CD28 (37.51)</td>
			<td>eBiosciences</td>
			<td>16-0281-85</td>
			<td></td>
		</tr>
		<tr>
			<td>e450-conjugated anti-mouse CD19 (eBio1D3)</td>
			<td>eBiosciences</td>
			<td>48-0193-82</td>
			<td></td>
		</tr>
		<tr>
			<td>e450-conjugated anti-mouse CD8&#945; (53-6.7)</td>
			<td>eBiosciences</td>
			<td>48-0081-82</td>
			<td></td>
		</tr>
		<tr>
			<td>FITC-conjugated anti-mouse CD5 (53-7.3)</td>
			<td>eBiosciences</td>
			<td>11-0051-81</td>
			<td></td>
		</tr>
		<tr>
			<td>V500-conjugated anti-mouse CD3&#949; (500A2)</td>
			<td>BD biosciences</td>
			<td>560771</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-mouse CD5 (Ly-1) microbeads</td>
			<td>Macs Miltenyi Biotec</td>
			<td>130-049-301</td>
			<td></td>
		</tr>
		<tr>
			<td>purified anti-mouse CD16/32 (2.4G2)</td>
			<td>Macs Miltenyi Biotec</td>
			<td>130-092-575</td>
			<td></td>
		</tr>
		<tr>
			<td>MACS MS Columns</td>
			<td>Macs Miltenyi Biotec</td>
			<td>130-042-201</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypan Blue, 0.4% (wt/vol)</td>
			<td>Gibco</td>
			<td>15250-061</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI 1640 medium</td>
			<td>Gibco</td>
			<td>12633-020</td>
			<td></td>
		</tr>
		<tr>
			<td>1x PBS</td>
			<td>Gibco</td>
			<td>10010-056</td>
			<td>[Ca2+/Mg2+ - free]</td>
		</tr>
		<tr>
			<td>Fetal calf serum</td>
			<td>Gibco</td>
			<td>10270</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Glutamine</td>
			<td>Gibco</td>
			<td>25030-123</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin-streptomycin</td>
			<td>Sigma-Aldrich</td>
			<td>P4458-100ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine serum albumin</td>
			<td>Sigma-Aldrich</td>
			<td>A7906-100MG</td>
			<td></td>
		</tr>
		<tr>
			<td>&#946;-Mercaptoethanol</td>
			<td>Sigma-Aldrich</td>
			<td>M3148</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethylenediaminetetraacetic acid&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>EDS-1KG</td>
			<td></td>
		</tr>
		<tr>
			<td>Ficoll-Paque plus</td>
			<td>GE Healthcare</td>
			<td>71-7167-00 AF</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>96-well plate F-bottom</td>
			<td>Greiner-bio one</td>
			<td>657-160</td>
			<td></td>
		</tr>
		<tr>
			<td>24-well plate</td>
			<td>Greiner-bio one</td>
			<td>665-180</td>
			<td></td>
		</tr>
		<tr>
			<td>6-well plate</td>
			<td>Greiner-bio one</td>
			<td>655-180</td>
			<td></td>
		</tr>
		<tr>
			<td>15 ml falcon tube</td>
			<td>Greiner-bio one</td>
			<td>188-271</td>
			<td></td>
		</tr>
		<tr>
			<td>50 ml falcon tube</td>
			<td>Greiner-bio one</td>
			<td>227-261</td>
			<td></td>
		</tr>
		<tr>
			<td>70 &#181;m filter</td>
			<td>Greiner-bio one</td>
			<td>542-070</td>
			<td></td>
		</tr>
		<tr>
			<td>30 &#181;m filter</td>
			<td>Millipore</td>
			<td>SVGP01050</td>
			<td></td>
		</tr>
		<tr>
			<td>MiniMACS separator</td>
			<td>Macs Miltenyi Biotec</td>
			<td>130-042-102</td>
			<td></td>
		</tr>
		<tr>
			<td>MS Columns</td>
			<td>Macs Miltenyi Biotec</td>
			<td>130-042-201</td>
			<td></td>
		</tr>
		<tr>
			<td>Water-jacketed CO2 incubator</td>
			<td>VWR</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hemocytometer</td>
			<td>VWR</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dissection Kit</td>
			<td>VWR</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>BD FACSAria III</td>
			<td>BD Biosciences</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

an optimized method for isolating and expanding invariant natural killer t cells from mouse spleen

The ability to rapidly secrete cytokines upon stimulation is a functional characteristic of the invariant natural killer T (iNKT) cell lineage. iNKT cells are therefore characterized as an innate T cell population capable of activating and steering adaptive immune responses. The development of improved techniques for the culture and expansion of murine iNKT cells facilitates the study of iNKT cell biology in in vitro and in vivo model systems. Here we describe an optimized procedure for the isolation and expansion of murine splenic iNKT cells.
Spleens from C57Bl/6 mice are removed, dissected and strained and the resulting cellular suspension is layered over density gradient media. Following centrifugation, splenic mononuclear cells (MNCs) are collected and CD5-positive (CD5+) lymphocytes are enriched for using magnetic beads. iNKT cells within the CD5+ fraction are subsequently stained with &#945;GalCer-loaded CD1d tetramer and purified by fluorescence activated cell sorting (FACS). FACS sorted iNKT cells are then initially cultured in vitro using a combination of recombinant murine cytokines and plate-bound T cell receptor (TCR) stimuli before being expanded in the presence of murine recombinant IL-7. Using this technique, approximately 108 iNKT cells can be generated within 18-20 days of culture, after which they can be used for functional assays in vitro, or for in vivo transfer experiments in mice.

Isolation of splenic mononuclear cells using a density gradient takes approximately 1 hr and eliminates the use of reagents required to lyse red blood cells (RBCs). A high yield of viable cells is obtained using this method and debris generated during straining of the organ is removed. Typically, the frequency of iNKT cells within the splenic lymphocyte pool ranges between 1 and 5% of total T lymphocytes however, this can vary depending on the age, sex and health status of the animals used. Approximately 106 i...

Watch this Scientific Journal Video about An Optimized Method for Isolating and Expanding Invariant Natural Killer T Cells from Mouse Spleen at JoVE.com

An Optimized Method for Isolating and Expanding Invariant Natural Killer T Cells from Mouse Spleen

Here we present an adapted protocol that can be used to generate a large number of murine invariant natural killer T cells from mouse spleen. The protocol outlines an approach by which splenic iNKT cells can be enriched for, isolated and expanded in vitro using a limited number of animals and reagents.

The ability to rapidly secrete cytokines upon stimulation is a functional characteristic of the invariant natural killer T (iNKT) cell lineage. iNKT cells ...

an-optimized-method-for-isolating-expanding-invariant-natural-killer

Research

JoVE Journal

Immunology and Infection

11.9K Views.  Ghent University Hospital. Here we present an adapted protocol that can be used to generate a large number of murine invariant natural killer T cells from mouse spleen. The protocol outlines an approach by which splenic iNKT cells can be enriched for, isolated and expanded in vitro using a limited number of animals and reagents. 

Video: An Optimized Method for Isolating and Expanding Invariant Natural Killer T Cells from Mouse Spleen

Preparation and Use of HIV-1 Infected Primary CD4+ T-Cells as Target Cells in Natural Killer Cell Cytotoxic Assays

Natural killer (NK) cells are a vital component of the innate immune response to virus-infected cells. It is important to understand the ability of NK cells to recognize and lyse HIV-1 infected cells because identifying any aberrancy in NK cell function against HIV-infected cells could potentially lead to therapies that would enhance their cytolytic activity. There is a need to use HIV-infected primary T-cell blasts as target cells rather then infected-T-cell lines in the cytotoxicity assays. T-cell lines, even without infection, are quite susceptible to NK cell lysis. Furthermore, it is necessary to use autologous primary cells to prevent major histocompatibility complex class I mismatches between the target and effector cell that will result in lysis. Early studies evaluating NK cell cytolytic responses to primary HIV-infected cells failed to show significant killing of the infected cells 1,2. However, using HIV-1 infected primary T-cells as target cells in NK cell functional assays has been difficult due the presence of contaminating uninfected cells 3. This inconsistent infected cell to uninfected cell ratio will result in variation in NK cell killing between samples that may not be due to variability in donor NK cell function. Thus, it would be beneficial to work with a purified infected cell population in order to standardize the effector to target cell ratios between experiments 3,4. Here we demonstrate the isolation of a highly purified population of HIV-1 infected cells by taking advantage of HIV-1's ability to down-modulate CD4 on infected cells and the availability of commercial kits to remove dead or dying cells 3-6. The purified infected primary T-cell blasts can then be used as targets in either a degranulation or cytotoxic assay with purified NK cells as the effector population 5-7. Use of NK cells as effectors in a degranulation assay evaluates the ability of an NK cell to release the lytic contents of specialized lysosomes 8 called "cytolytic granules". By staining with a fluorochrome conjugated antibody against CD107a, a lysosomal membrane protein that becomes expressed on the NK cell surface when the cytolytic granules fuse to the plasma membrane, we can determine what percentage of NK cells degranulate in response to target cell recognition. Alternatively, NK cell lytic activity can be evaluated in a cytotoxic assay that allows for the determination of the percentage of target cells lysed by release of 51Cr from within the target cell in the presence of NK cells.

Cytotoxicity assays to measure natural killer cell lytic responses to HIV-infected cells is limited by the purity of the target cells. We demonstrate here the isolation of a highly purified population of HIV-1 infected primary T-cell blasts by taking advantage of HIV-1 s ability to down-modulate CD4.

 Natural killer (NK) cells are a vital component of the innate immune response to virus-infected cells. It is important to understand the ability of NK ...

Expanding Cytotoxic T Lymphocytes from Umbilical Cord Blood that Target Cytomegalovirus, Epstein-Barr Virus, and Adenovirus

Virus infections after stem cell transplantation are among the most common causes of death, especially after cord blood (CB) transplantation (CBT) where the CB does not contain appreciable numbers of virus-experienced T cells which can protect the recipient from infection.1-4 We and others have shown that virus-specific CTL generated from seropositive donors and infused to the recipient are safe and protective.5-8 However, until recently, virus-specific T cells could not be generated from cord blood, likely due to the absence of virus-specific memory T cells. 
In an effort to better mimic the in vivo priming conditions of na&iuml;ve T cells, we established a method that used CB-derived dendritic cells (DC) transduced with an adenoviral vector (Ad5f35pp65) containing the immunodominant CMV antigen pp65, hence driving T cell specificity towards CMV and adenovirus.9 At initiation, we use these matured DCs as well as CB-derived T cells in the presence of the cytokines IL-7, IL-12, and IL-15.10 At the second stimulation we used EBV-transformed B cells, or EBV-LCL, which express both latent and lytic EBV antigens. Ad5f35pp65-transduced EBV-LCL are used to stimulate the T cells in the presence of IL-15 at the second stimulation. Subsequent stimulations use Ad5f35pp65-transduced EBV-LCL and IL-2. 
From 50x106 CB mononuclear cells we are able to generate upwards of 150 x 106 virus-specific T cells that lyse antigen-pulsed targets and release cytokines in response to antigenic stimulation.11 These cells were manufactured in a GMP-compliant manner using only the 20% fraction of a fractionated cord blood unit and have been translated for clinical use.

Here we describe the first good manufacturing practice (GMP)-compliant method of producing virus-specific cytotoxic T lymphocytes (CTL) from umbilical cord blood, a source of predominantly na&#238;ve T cells.

Virus infections after stem cell transplantation are among the most common causes of death, especially after cord blood (CB) transplantation (CBT) where ...

Artificial Antigen Presenting Cell (aAPC) Mediated Activation and Expansion of Natural Killer T Cells

Natural killer T (NKT) cells are a unique subset of T cells that display markers characteristic of both natural killer (NK) cells and T cells1. Unlike classical T cells, NKT cells recognize lipid antigen in the context of CD1 molecules2. NKT cells express an invariant TCR&alpha; chain rearrangement: V&alpha;14J&alpha;18 in mice and V&alpha;24J&alpha;18 in humans, which is associated with V&beta; chains of limited diversity3-6, and are referred to as canonical or invariant NKT (iNKT) cells. Similar to conventional T cells, NKT cells develop from CD4-CD8- thymic precursor T cells following the appropriate signaling by CD1d 7. The potential to utilize NKT cells for therapeutic purposes has significantly increased with the ability to stimulate and expand human NKT cells with &alpha;-Galactosylceramide (&alpha;-GalCer) and a variety of cytokines8. Importantly, these cells retained their original phenotype, secreted cytokines, and displayed cytotoxic function against tumor cell lines. Thus, ex vivo expanded NKT cells remain functional and can be used for adoptive immunotherapy. However, NKT cell based-immunotherapy has been limited by the use of autologous antigen presenting cells and the quantity and quality of these stimulator cells can vary substantially. Monocyte-derived DC from cancer patients have been reported to express reduced levels of costimulatory molecules and produce less inflammatory cytokines9,10. In fact, murine DC rather than autologous APC have been used to test the function of NKT cells from CML patients11. However, this system can only be used for in vitro testing since NKT cells cannot be expanded by murine DC and then used for adoptive immunotherapy. Thus, a standardized system that relies on artificial Antigen Presenting Cells (aAPC) could produce the stimulating effects of DC without the pitfalls of allo- or xenogeneic cells12, 13. Herein, we describe a method for generating CD1d-based aAPC. Since the engagement of the T cell receptor (TCR) by CD1d-antigen complexes is a fundamental requirement of NKT cell activation, antigen: CD1d-Ig complexes provide a reliable method to isolate, activate, and expand effector NKT cell populations.

Artificial Antigen Presenting Cell aAPC Mediated Activation and Expansion of Natural Killer T Cells

Here we describe a method for activating and expanding human NKT cells from bulk T cell populations using artificial antigen presenting cells (aAPC). The use of CD1d-based aAPC provides a standardized method for generating high numbers of functional NKT cells.

Natural killer T (NKT) cells are a unique subset of T cells that display markers characteristic of both natural killer (NK) cells and T cells1. Unlike ...

Killer Artificial Antigen Presenting Cells (KaAPC) for Efficient In Vitro Depletion of Human Antigen-specific T Cells

Current treatment of T cell mediated autoimmune diseases relies mostly on strategies of global immunosuppression, which, in the long term, is accompanied by adverse side effects such as a reduced ability to control infections or malignancies. Therefore, new approaches need to be developed that target only the disease mediating cells and leave the remaining immune system intact. Over the past decade a variety of cell based immunotherapy strategies to modulate T cell mediated immune responses have been developed. Most of these approaches rely on tolerance-inducing antigen presenting cells (APC). However, in addition to being technically difficult and cumbersome, such cell-based approaches are highly sensitive to cytotoxic T cell responses, which limits their therapeutic capacity. Here we present a protocol for the generation of non-cellular killer artificial antigen presenting cells (KaAPC), which allows for the depletion of pathologic T cells while leaving the remaining immune system untouched and functional. KaAPC is an alternative solution to cellular immunotherapy which has potential for treating autoimmune diseases and allograft rejections by regulating undesirable T cell responses in an antigen specific fashion.

Killer Artificial Antigen Presenting Cells KaAPC for Efficient In Vitro Depletion of Human Antigen-specific T Cells

Guidelines are presented for the generation of killer artificial antigen presenting cells, KaAPC, an efficient tool for in vitro depletion of human antigen-specific T cells and an alternative solution to cellular immunotherapy for the treatment of T cell-mediated autoimmune diseases in an antigen-specific fashion without compromising the remaining immune system.

Current treatment of T cell mediated autoimmune diseases relies mostly on strategies of global immunosuppression, which, in the long term, is accompanied ...

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 ...

Flow Cytometric Analysis of Natural Killer Cell Lytic Activity in Human Whole Blood

NK cell cytotoxicity is a widely used measure to determine the effect of outside intervention on NK cell function. However, the accuracy and reproducibility of this assay can be considered unstable, either because of user&#39;s errors or because of the sensitivity of NK cells to experimental manipulation. To eliminate these issues, a workflow that reduces them to a minimum was established and is presented here. To illustrate, we obtained blood samples, at various time points, from runners (n = 4) that were submitted to an intense bout of exercise. First, NK cells are simultaneously identified and isolated through CD56 tagging and magnetic-based sorting, directly from whole blood and from as little as one milliliter. The sorted NK cells are removed of any reagent or capping antibodies. They can be counted in order to establish an accurate NK cell count per milliliter of blood. Secondly, the sorted NK cells (effectors cells or E) can be mixed with 3,3&#39;-Diotadecyloxacarbocyanine Perchlorate (DiO) tagged K562 cells (target cells or T) at an assay-optimal 1:5 T:E ratio, and analyzed using an imaging flow-cytometer that allows for the visualization of each event and the elimination of any false positive or false negatives (such as doublets or effector cells). This workflow can be completed in about 4 h, and allows for very stable results even when working with human samples. When available, research teams can test several experimental interventions in human subjects, and compare measurements across several time points without compromising the data&#39;s integrity.

This work describes an advanced workflow for the accurate and fast determination of NK (Natural Killer) cell count and NK cell cytotoxicity in human blood samples.

NK cell cytotoxicity is a widely used measure to determine the effect of outside intervention on NK cell function. However, the accuracy and ...

A Novel Feeder-free System for Mass Production of Murine Natural Killer Cells In Vitro

Natural killer (NK) cells belong to the innate immune system and are a first-line anti-cancer immune defense; however, they are suppressed in the tumor microenvironment and the underlying mechanism is still largely unknown. The lack of a consistent and reliable source of NK cells limits the research progress of NK cell immunity. Here, we report an in vitro system that can provide high quality and quantity of bone marrow-derived murine NK cells under a feeder-free condition. More importantly, we also demonstrate that siRNA-mediated gene silencing successfully inhibits the E4bp4-dependent NK cell maturation by using this system. Thus, this novel in vitro NK cell differentiating system is a biomaterial solution for immunity research.

A Novel Feeder-free System for Mass Production of Murine Natural Killer Cells In Vitro

Here, we present a protocol to mass-produce gene-silencing murine NK cells by using a feeder-free differentiation system for mechanistic study in vitro and in vivo.

Natural killer (NK) cells belong to the innate immune system and are a first-line anti-cancer immune defense; however, they are suppressed in the tumor ...

Isolating Lymphocytes from the Mouse Small Intestinal Immune System

The intestinal immune system plays an essential role in maintaining the barrier function of the gastrointestinal tract by generating tolerant responses to dietary antigens and commensal bacteria while mounting effective immune responses to enteropathogenic microbes. In addition, it has become clear that local intestinal immunity has a profound impact on distant and systemic immunity. Therefore, it is important to study how an intestinal immune response is induced and what the immunologic outcome of the response is. Here, a detailed protocol is described for the isolation of lymphocytes from small intestine inductive sites like the gut-associated lymphoid tissue Peyer&#39;s patches and the draining mesenteric lymph nodes and effector sites like the lamina propria and the intestinal epithelium. This technique ensures isolation of a large numbers of lymphocytes from small intestinal tissues with optimal purity and viability and minimal cross compartmental contamination within acceptable time constraints. The technical capability to isolate lymphocytes and other immune cells from intestinal tissues enables the understanding of immune responses to gastrointestinal infections, cancers, and inflammatory diseases.

Here we describe a detailed protocol for the isolation of lymphocytes from the inductive sites including the gut-associated lymphoid tissue Peyer&#39;s patches and the draining mesenteric lymph nodes, and the effector sites including the lamina propria and the intestinal epithelium of the small intestinal immune system.

The intestinal immune system plays an essential role in maintaining the barrier function of the gastrointestinal tract by generating tolerant responses to ...

Multicolor Flow Cytometry-based Quantification of Mitochondria and Lysosomes in T Cells

T cells utilize different metabolic programs to match their functional needs during differentiation and proliferation. Mitochondria are crucial cellular components responsible for supplying cell energy; however, excess mitochondria also produce reactive oxygen species (ROS) that could cause cell death. Therefore, the number of mitochondria must constantly be adjusted to fit the needs of the cells. This dynamic regulation is achieved in part through the function of lysosomes that remove surplus/damaged organelles and macromolecules. Hence, cellular mitochondrial and lysosomal contents are key indicators to evaluate the metabolic adjustment of cells. With the development of probes for organelles, well-characterized lysosome or mitochondria-specific dyes have become available in various formats to label cellular lysosomes and mitochondria. Multicolor flow cytometry is a common tool to profile cell phenotypes, and has the capability to be integrated with other assays. Here, we present a detailed protocol of how to combine organelle-specific dyes with surface markers staining to measure the amount of lysosomes and mitochondria in different T cell populations on a flow cytometer.

This article illustrates a powerful method to quantify mitochondria or lysosomes in living cells. The combination of lysosome- or mitochondria-specific dyes with fluorescently conjugated antibodies against surface markers allows the quantification of these organelles in mixed cell populations, like primary cells harvested from tissue samples, by using multicolor flow cytometry.

T cells utilize different metabolic programs to match their functional needs during differentiation and proliferation. Mitochondria are crucial cellular ...

Analysis of Human Natural Killer Cell Metabolism

Natural Killer (NK) cells mediate mainly innate anti-tumor and anti-viral immune responses and respond to a variety of cytokines and other stimuli to promote survival, cellular proliferation, production of cytokines such as interferon gamma (IFN&#947;) and/or cytotoxicity programs. NK cell activation by cytokine stimulation requires a substantial remodeling of metabolic pathways to support their bioenergetic and biosynthetic requirements. There is a large body of evidence that suggests that impaired NK cell metabolism is associated with a number of chronic diseases including obesity and cancer, which highlights the clinical importance of the availability of a method to determine NK cell metabolism. Here we describe the use of an extracellular flux analyzer, a platform that allows real-time measurements of glycolysis and mitochondrial oxygen consumption, as a tool to monitor changes in the energy metabolism of human NK cells. The method described here also allows for the monitoring of metabolic changes after stimulation of NK cells with cytokines such as IL-15, a system that is currently being investigated in a wide range of clinical trials.

In this paper, we describe a method to measure glycolysis and mitochondrial respiration in primary human Natural Killer (NK) cells isolated from peripheral blood, at rest or following IL15-induced activation. The protocol described could be easily extended to primary human NK cells activated by other cytokines or soluble stimuli.

Natural Killer (NK) cells mediate mainly innate anti-tumor and anti-viral immune responses and respond to a variety of cytokines and other stimuli to ...