Name: a novel feeder-free system for mass production of murine natural killer cells in vitro
Uploaded: 2018-01-09T14:00:00
Description: Watch this Scientific Journal Video about A Novel Feeder-free System for Mass Production of Murine Natural Killer Cells In Vitro at JoVE.com

This study was supported by the Research Grants Council of Hong Kong (GRF 468513, CUHK3/CRF/12R) and the Innovation and Technology Fund of Hong Kong (ITS/227/15, ITS InP/164/16, ITS-InP/242/16), Direct Grant for Research-CUHK (2016.035), and Hong Kong Scholar Program.
H.-Y.L. designed and supervised all experiments and contributed to manuscript preparation. P.M.-K.T. performed experiments, analyzed data and contributed to manuscript preparation. P.C.-T. T., J.Y.-F.C., J.S.-C.,H., Q.-M.W., and G.-Y.L. collected animal samples and participated in animal experiments. J.S., X.-R.H., and K.-F.T. contributed to manuscript preparation.

The protocol for obtaining and differentiating bone marrow-derived NK cells (BM-NK) is based on previously published methods20,21,22. All procedures with mice have been approved by the Animal Ethics Experimental Committee (AEEC) at the Chinese University of Hong Kong.
1. Preparation of OP9 Conditional Medium
<ol>
	<li>Culture the murine stroma cell line OP9 in alpha-MEM containing 20% FBS, 100 U/mL ...

<ol>
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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+TGF-&#946;/SMAD+pathway+is+an+important+mechanism+for+NK+cell+immune+evasion+in+childhood+B-acute+lymphoblastic+leukemia.">The TGF-&#946;/SMAD pathway is an important mechanism for NK cell immune evasion in childhood B-acute lymphoblastic leukemia.</a> Leukemia. 30 (4), 800-811 (2016).</li><li>Derynck, R., Akhurst, R. J., Balmain, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TGF-&#946;+signaling+in+tumor+suppression+and+cancer+progression.">TGF-&#946; signaling in tumor suppression and cancer progression.</a> Nature Genet. 29 (2), 117-129 (2001).</li><li>Massague, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TGFbeta+in+cancer.">TGFbeta in cancer.</a> Cell. 134 (2), 215-230 (2008).</li><li>Ikushima, H., Miyazono, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TGFbeta+signalling:+a+complex+web+in+cancer+progression.">TGFbeta signalling: a complex web in cancer progression.</a> Nat Rev Cancer. 10 (6), 415-424 (2010).</li><li>Pickup, M., Novitskiy, S., Moses, H. 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+roles+of+TGF&#946;+in+the+tumour+microenvironment.">The roles of TGF&#946; in the tumour microenvironment.</a> Nat Rev Cancer. 13 (11), 788-799 (2013).</li><li>Rook, A. 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=Effects+of+transforming+growth+factor+beta+on+the+functions+of+natural+killer+cells:+depressed+cytolytic+activity+and+blunting+of+interferon+responsiveness.">Effects of transforming growth factor beta on the functions of natural killer cells: depressed cytolytic activity and blunting of interferon responsiveness.</a> J Immunol. 136 (10), 3916-3920 (1986).</li><li>Bellone, G., Aste-Amezaga, M., Trinchieri, G., Rodeck, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+NK+cell+functions+by+TGF-beta+1.">Regulation of NK cell functions by TGF-beta 1.</a> J Immunol. 155 (3), 1066-1073 (1995).</li><li>Trotta, R., 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=TGF-&#946;+utilizes+SMAD3+to+inhibit+CD16-mediated+IFN-&#947;+production+and+antibody-dependent+cellular+cytotoxicity+in+human+NK+cells.">TGF-&#946; utilizes SMAD3 to inhibit CD16-mediated IFN-&#947; production and antibody-dependent cellular cytotoxicity in human NK cells.</a> J Immunol. 181 (6), 3784-3792 (2008).</li><li>Shull, M. 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=Targeted+disruption+of+the+mouse+transforming+growth+factor-&#946;1+gene+results+in+multifocal+inflammatory+disease.">Targeted disruption of the mouse transforming growth factor-&#946;1 gene results in multifocal inflammatory disease.</a> Nature. 359 (6397), 693-699 (1992).</li><li>Chen, T. J., Kotecha, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytobank:+providing+an+analytics+platform+for+community+cytometry+data+analysis+and+collaboration.">Cytobank: providing an analytics platform for community cytometry data analysis and collaboration.</a> Curr Top Microbiol Immunol. 377, 127-157 (2014).</li><li>Williams, N. 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=Differentiation+of+NK1.1+,+Ly49++NK+cells+from+flt3++multipotent+marrow+progenitor+cells.">Differentiation of NK1.1+, Ly49+ NK cells from flt3+ multipotent marrow progenitor cells.</a> J Immunol. 163 (5), 2648-2656 (1999).</li><li>Fathman, 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=Identification+of+the+earliest+natural+killer+cell-committed+progenitor+in+murine+bone+marrow.">Identification of the earliest natural killer cell-committed progenitor in murine bone marrow.</a> Blood. 118 (20), 5439-5447 (2011).</li><li>Tang, P. 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In the present work, we have described a novel method for producing bone marrow-derived murine NK cells in vitro. The cell feeder in the original system21,22 is successfully replaced by the conditional medium of OP9 cells, which largely increased the stability of the differentiation system. In addition, the system can produce high quantity and purity of mature NK cells for in vitro as well as in vivo assays, which can facilitate the mec...

Cancer progression is largely dependent on the tumor microenvironment1,2, including host-derived immunocytes, e.g., NK cells. Several studies demonstrated that intratumoral NK cells are negatively correlated with the tumor progression3,4. In addition, clinical studies showed that NK cell adoptive therapy is a possible strategy for cancer5,6,7,8,9. NK cell-based cancer immunotherapy was recently suggested as a therapeutic option for solid tumors, but challenges exist due to the secretion of immunosuppressive cytokines and downregulation of activating ligands in the microenvironment of solid tumors10,11. Transforming growth factor-&#946; (TGF-&#946;) has been suggested to play a suppressive role in carcinogenesis, but paradoxically cancer cells also produce TGF-&#946;1 to support the tumor development12,13,14,15. TGF-&#946; signaling can suppress the cytolytic activity of NK cells via down-regulating interferon responsiveness and CD16-mediated interferon-gamma (IFN-&#947;) production in vitro16,17,18.
Although disruption of TGF-&#946; signaling in the tumor microenvironment may be a possible way for eliminating cancers, completely blocking TGF-&#946; signaling will cause autoimmune diseases due to its anti-inflammatory function, as evidenced by the development of adverse side effects including systemic inflammation, cardiovascular defects, and autoimmunity in mouse models19. Thus, understanding the working mechanism of TGF-&#946;-mediated immunosuppression will lead to the identification of an accessible therapeutic target for treating cancer.
To elucidate the molecular events necessary for NK cell development, Williams et al. established an in vitro system for differentiating murine bone marrow hematopoietic stem cells into NK cells20. This system largely facilitates the mechanistic study of NK cell development, including the identification of novel progenitors of NK cells21. However, the bone marrow progenitors should be cultured in the system with supporting OP9 stromal cells as a feeder layer20,21, and this heterogeneous cell population largely limits the further application of gene-disrupting tools (e.g., siRNA-mediated gene silencing) specifically applied to the differentiating NK cells.
Here, we describe a feeder-free system that has been developed by further modifying the in vitro system of Williams et al20. In our system, the OP9 stromal feeder cells are not required, and instead OP9 conditional medium is used without affecting the differentiation of NK cells in vitro, and this recently lead us to uncover that TGF-&#946; is able to promote cancer progression via suppressing E4bp4-dependent NK cell development in the tumor microenvironment22. This novel system successfully provides a background-free method for elucidating the molecular mechanism of NK cell development under specific conditions (e.g., high TGF- &#946;1, siRNA-mediated gene silencing, etc.) in vitro.

<table border="0" cellpadding="0" cellspacing="0" style="width:1113px;" width="1113">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:297px;">OP9 cell line</td>
			<td style="width:129px;">ATCC</td>
			<td style="width:344px;">ATCC&#174; CRL-2749&#8482;</td>
			<td style="width:343px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">MEM &#945;, no nucleosides</td>
			<td>Gibco</td>
			<td>22561021</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Fetal Bovine Serum</td>
			<td>Gibco</td>
			<td>10500064</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">PBS, pH 7.4</td>
			<td>Gibco</td>
			<td>10010049</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Recombinant Murine IL-7</td>
			<td>PEPROTECH</td>
			<td>217-17</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Recombinant Murine SCF</td>
			<td>PEPROTECH</td>
			<td>250-03</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Recombinant Murine Flt3-Ligand</td>
			<td>PEPROTECH</td>
			<td>250-31L</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Recombinant Murine IL-2</td>
			<td>PEPROTECH</td>
			<td>212-12</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Lipofectamin RNAiMAX Transfection Reagent</td>
			<td>Invitrogen</td>
			<td>1377815</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">IC Fixation Buffer&#160;</td>
			<td>eBioscience</td>
			<td>00-8222-49</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Flow Cytometry Staining Buffer&#160;</td>
			<td>eBioscience</td>
			<td>00-4222-26</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">PE-conjugated anti-mouse CD244</td>
			<td>eBioscience</td>
			<td>12-2441-83</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Cy3-conjugated anti-mouse NKp46</td>
			<td>Bioss</td>
			<td>bs-2417R-cy3</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Nonsense control (NC)</td>
			<td>Ribobio</td>
			<td>siN05815122147</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">siRNA against mouse E4BP4 mRNA</td>
			<td>Ribobio</td>
			<td>N/A</td>
			<td>5&#8242;-GAUGAGGGUGUA 
			GUGGGCAAGUCUU-3&#8242;</td>
		</tr>
	</tbody>
</table>

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.

Representative results are obtained following the described protocol. Total bone marrow suspension cells were cultivated under the feeder-free differentiation system for 11 days; significant increase in proliferation rate was observed by day 7 compared with the number of total cells on day 0 (Figure 1A). Mature NK cells with high nuclear to cytoplasmic ratio and granule-rich cytoplasm morphology were found by day 6 in the system (<strong clas...

Watch this Scientific Journal Video about A Novel Feeder-free System for Mass Production of Murine Natural Killer Cells In Vitro at JoVE.com

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.

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 ...

The overall goal of this novel feeder-free system is to provide a method to mass produce high-purity natural killer cells for in vitro as well as in vivo assays. This method can help answer the key questions in innate immunology, including natural killer cell development and cancer immunity. The main advantage of this technique is that this novel feeder-free system can largely increase the purity of the produced natural killer cells.That significantly facilitates the following assays in vitro and in vivo. The indication of this technique extends to the natural killer immunity because mass production of murine natural killer cells can be produced from the bone marrow of cancer patients for analysis and modification for personal immunotherapy. Generally, individuals new to this method will struggle because the consumed medium should be collected from the OP9 cell undergoing load phase growth.Facial demonstration of this method is critical as the bone marrow instruction steps are difficult to learn, because the bones need to be sterile with ethanol with optimal time to preserve the viability. To begin this procedure, collect the OP9 cells from a culture flask. Add FBS to stop trypsin digestion.Collect the OP9 cells, and centrifuge at 465 times gravity for five minutes. After this, re-suspend the cell pellet. Using a hemocytometer, count the cells.Then, seed two times 10-to-the-six cells in 15 milliliters of alpha-mem medium in a 75 centimeter-square culture flask, and incubate for 48 hours. Once the cells are 80%confluent, wash the cells with 10 millimeters of phosphate-buffered saline and add 20 milliliters of plain alpha-mem medium without antibiotics and fetal bovine serum to the cells. Incubate for 24 hours.The next day, collect the OP9-conditioned media by removing the cell debris with a filter and preserve at four degrees Celsius. Inject overdose of 100 milligrams per kilogram of pentobarbitone intraperitoneal to euthanize a 12-week-old mouse. After confirming lack of breathing, excise the femur bones with a surgical knife.Remove the remaining muscles by gently scratching with a blade. Transfer the bones in a 50 milliliter centrifuge tube filled with chilled, sterile alpha-mem medium, and keep in a biosafety cabinet. Then, expel the alpha-mem medium, and wash the bones with 70%ethanol for 30 seconds.Again, wash the bones with ice-cold sterile phosphate-buffered saline twice to remove any remaining ethanol. After washing, transfer the bones to a mortar containing five milliliters of ice-cold phosphate-buffered saline and fragmentize the bones with a pestle. Swirl the pestle gently to release the bone marrow cells into the phosphate-buffered saline.Transfer the phosphate-buffered saline containing bone marrow cells in a new 50 milliliter centrifuge tube. Then, centrifuge the tube at 465 times gravity for five minutes at four degrees Celsius. After centrifugation, discard the supernatant.Extract until the bone turns white in color to get maximum yield. Next, re-suspend the pellet with 18 milliliters of sterile distilled water, and wait for 30 seconds to remove the red blood cells. Then, add two milliliters of 10X ice-cold phosphate-buffered saline to stop the reaction.Use a 70 micrometer cell strainer to remove the lysed red blood cells. Then, centrifuge the tubes at 465 times gravity for five minutes at four degrees Celsius. Discard the supernatant and re-suspend the pellet in 20 milliliters of ice-cold phosphate-buffered saline.Centrifuge the cells one more time. Next, transfer the cell pellet in a 100 milliliter sterile petri dish containing 10 milliliters of OP9 conditional medium, supplemented with additional reagents. Transfer the petri dish in an incubator at 37 degrees Celsius with 5%carbon dioxide for two hours.Remove all unattached cells and seed in a new culture dish containing OP9 conditional medium, and place in an incubator at 37 degrees Celsius for five minutes. On the fourth day, replace the culture medium with OP9 conditional medium, supplemented with 20%fetal bovine serum and 2, 000 units per milliliter of murine interleukin 2. Keep changing the culture medium every three days until the seventh day to obtain the mature natural killer cells.Follow the product manual to premix the small interfering RNA or non-sense control with the transfection reagent at zero, fourth and seventh day of changing the medium until the experimental endpoint. Add 50 nanomolar of small interfering RNA, or non-sense mixture, to the unattached cells during medium refreshment. Collect the differentiating cells at an appropriate timepoint.Centrifuge the cells at 465 times gravity for five minutes. Discard the supernatant and wash the cell pellet with ice-cold phosphate-buffered saline. After washing the fixed cells with ice-cold phosphate-buffered saline, re-suspend the cells in 100 microliters of flow cytometry staining buffer containing SY3 conjugated antibodies.After this, re-suspend the samples in 300 microliters of phosphate-buffered saline for fax analysis. A representative growth curve demonstrating the proliferation rate of the bone marrow cells undergoing differentiation into natural killer cells in feeder-free system. The graph shows a significant increase in the proliferation rate of the cells by Day Seven.A representative bright field image showing differentiated natural killer cells in a novel feeder-free system. Mature natural killer cells exhibited high nuclear to cytoplasmic ratio with a granular cytoplasmic morphology. A representative bar plot showing the effect of small interfering RNA on the bone marrow cells undergoing differentiation into natural killer cells on Day Six.The plot shows significant reduction on the E4bp4 mRNA levels and small interfering RNA treated natural killer cells compared to the control group. A representative flow cytometric data demonstrating the effect of silenced E4bp4 on the differentiation of bone marrow derived natural killer cells in a TGF beta-1 Smad3-dependent manner. Data shows knockdown of E4bp4 mRNA vastly decreases in mature natural killer cell production on Day Six in comparison to the non-sense control.Small interfering RNA mediated decreased production of natural killer cells is shown to be rescued by suppressing TGF beta-1 Smad3 with one micromolar SIS3 Smad3 inhibitor in comparison to the small interfering RNA transfected group. Once mastered, this study can be done in two hours if it's performed properly. Following this procedure allows genetic modifications such as gene lockdown and over-expression can be conducted in order to answer additional questions like the regulation mechanisms for natural killer cell activity as well as the development.The first I had the idea for this method when I was expanding the natural killer cells in the old system. The presence of the fetal cells decreased the load and efficiency of siRNA to the interest gene. After watching this video, you should have a good understanding of how to produce massive high-quality natural killer cells from this local system in vitro.Don't forget that working with RNA extraction reagents can be extremely hazardous, and precautions should always be taken while performing this procedure.

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Immunology and Infection

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 ...

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 ...

A Novel In vitro Model for Studying the Interactions Between Human Whole Blood and Endothelium

The majority of all known diseases are accompanied by disorders of the cardiovascular system. Studies into the complexity of the interacting pathways activated during cardiovascular pathologies are, however, limited by the lack of robust and physiologically relevant methods. In order to model pathological vascular events we have developed an in vitro assay for studying the interaction between endothelium and whole blood. The assay consists of primary human endothelial cells, which are placed in contact with human whole blood. The method utilizes native blood with no or very little anticoagulant, enabling study of delicate interactions between molecular and cellular components present in a blood vessel.
We investigated functionality of the assay by comparing activation of coagulation by different blood volumes incubated with or without human umbilical vein endothelial cells (HUVEC). Whereas a larger blood volume contributed to an increase in the formation of thrombin antithrombin (TAT) complexes, presence of HUVEC resulted in reduced activation of coagulation. Furthermore, we applied image analysis of leukocyte attachment to HUVEC stimulated with tumor necrosis factor (TNF&#945;) and found the presence of CD16+ cells to be significantly higher on TNF&#945; stimulated cells as compared to unstimulated cells after blood contact. In conclusion, the assay may be applied to study vascular pathologies, where interactions between the endothelium and the blood compartment are perturbed.

A Novel In vitro Model for Studying the Interactions Between Human Whole Blood and Endothelium

The accessibility of reliable models to investigate vascular blood interactions in humans is lacking. We present an in vitro model of cultured primary human endothelial cells combined with human whole blood to investigate cellular interactions both in the blood (ELISA) and the vascular compartment (microscopy).

The majority of all known diseases are accompanied by disorders of the cardiovascular system. Studies into the complexity of the interacting pathways ...

Super-resolution Imaging of the Natural Killer Cell Immunological Synapse on a Glass-supported Planar Lipid Bilayer

The glass-supported planar lipid bilayer system has been utilized in a variety of disciplines. One of the most useful applications of this technique has been in the study of immunological synapse formation, due to the ability of the glass-supported planar lipid bilayers to mimic the surface of a target cell while forming a horizontal interface. The recent advances in super-resolution imaging have further allowed scientists to better view the fine details of synapse structure. In this study, one of these advanced techniques, stimulated emission depletion (STED), is utilized to study the structure of natural killer (NK) cell synapses on the supported lipid bilayer. Provided herein is an easy-to-follow protocol detailing: how to prepare raw synthetic phospholipids for use in synthesizing glass-supported bilayers; how to determine how densely protein of a given concentration occupies the bilayer's attachment sites; how to construct a supported lipid bilayer containing antibodies against NK cell activating receptor CD16; and finally, how to image human NK cells on this bilayer using STED super-resolution microscopy, with a focus on distribution of perforin positive lytic granules and filamentous actin at NK synapses. Thus, combining the glass-supported planar lipid bilayer system with STED technique, we demonstrate the feasibility and application of this combined technique, as well as intracellular structures at NK immunological synapse with super-resolution.

We describe here a combination of the glass-supported lipid bilayer technique of forming immunological synapses with the super-resolution imaging technique of stimulated emission depletion (STED) microscopy. The goal of this protocol is to provide users with the instructions necessary to successfully carry out these two techniques.

The glass-supported planar lipid bilayer system has been utilized in a variety of disciplines. One of the most useful applications of this technique has ...

In Vitro Generation of Murine Plasmacytoid Dendritic Cells from Common Lymphoid Progenitors using the AC-6 Feeder System

Plasmacytoid dendritic cells (pDCs) are powerful type I interferon (IFN-I) producing cells that are activated in response to infection or during inflammatory responses. Unfortunately, study of pDC function is hindered by their low frequency in lymphoid organs, and existing methods for in vitro DC generation predominantly favor the production of cDCs over pDCs. Here we present a unique approach to efficiently generate pDCs from common lymphoid progenitors (CLPs) in vitro. Specifically, the protocol described details how to purify CLPs from bone marrow and generate pDCs by coculturing with &#947;-irradiated AC-6 feeder cells in the presence of Flt3 ligand. A unique characteristic of this culture system is that the CLPs migrate underneath the AC-6 cells and become cobblestone area-forming cells, a critical step for expanding pDCs. Morphologically distinct DCs, namely pDCs and cDCs, were generated after approximately 2 weeks with a composition of 70-90% pDCs under optimal conditions. Typically, the number of pDCs generated by this method is roughly 100-fold of the number of CLPs seeded. Therefore, this is a novel system with which to robustly generate the large numbers of pDCs required to facilitate further studies into the development and function of these cells.

In Vitro Generation of Murine Plasmacytoid Dendritic Cells from Common Lymphoid Progenitors using the AC-6 Feeder System

In this study we present an in vitro culture system that can efficiently generate pDCs by co-culturing common lymphoid progenitors with AC-6 feeder cells in the presence of Flt3 ligand.

Plasmacytoid dendritic cells (pDCs) are powerful type I interferon (IFN-I) producing cells that are activated in response to infection or during ...

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.

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 ...

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 In Vitro Wound Healing Assay to Evaluate Cell Migration

The aim of this work is to show a novel method to evaluate the ability of some immunomodulatory molecules, such as antimicrobial peptides (AMPs), to stimulate cell migration. Importantly, cell migration is a rate-limiting event during the wound-healing process to re-establish the integrity and normal function of tissue layers after injury. The advantage of this method over the classical assay, which is based on a manually made scratch in a cell monolayer, is the usage of special silicone culture inserts providing two compartments to create a cell-free pseudo-wound field with a well-defined width (500 &#956;m). In addition, due to an automated image analysis platform, it is possible to rapidly obtain quantitative data on the speed of wound closure and cell migration. More precisely, the effect of two frog-skin AMPs on the migration of bronchial epithelial cells will be shown. Furthermore, pretreatment of these cells with specific inhibitors will provide information on the molecular mechanisms underlying such events.

A Novel In Vitro Wound Healing Assay to Evaluate Cell Migration

Here, we present a protocol to evaluate the effect of peptides on the migration of bronchial epithelial cells. This method allows for the rapid and highly reproducible obtainment of quantitative data on the speed of cell migration and wound closure.

The aim of this work is to show a novel method to evaluate the ability of some immunomodulatory molecules, such as antimicrobial peptides (AMPs), to ...

A Plate-based Cytotoxicity Assay for the Assessment of Rat Placental Natural Killer Cell Cytolytic Function

It is well known that decidual natural killer (NK) cells play a critical role in establishment and maintenance of normal pregnancy. Recent studies have demonstrated an altered population of circulating and decidual NK cells in women who suffer from adverse pregnancy complications such as recurrent miscarriage and preeclampsia. Studies from our group have shown that hypertension in pregnancy is associated with an increased population of activated NK cells in the placenta based on the expression of surface activation markers. This manuscript provides a detailed protocol to assess the cytotoxic function of NK cells isolated from placentas in a preeclampsia-like animal model of surgically induced placental ischemia. The following steps are described in detail: generation of single cell suspension, NK cell isolation, ex vivo stimulation, effector:target cell co-culture, and the cytotoxicity assay.

Here, we provide a detailed methodology to isolate and assess cytotoxic function of natural killer cells from placentas by a colorimetric plate assay. The reduced uterine perfusion pressure rat model of placental ischemia was chosen to demonstrate the antibody-mediated isolation and assessment of the cytotoxic function of natural killer cells.

It is well known that decidual natural killer (NK) cells play a critical role in establishment and maintenance of normal pregnancy. Recent studies have ...