We are grateful for technical assistance from Alison Church Bird at the Auburn University School of Veterinary Medicine Flow Cytometry Facility, for funding from the NIH to EHS R15 R15 AI107773 and to the Cellular and Molecular Biology Program at Auburn University for summer research funding to PBR.

All animal work was approved by the Auburn University Institutional Animal Care and Use Committee in accordance with the recommendations outlined in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health.
1. Preparation for Bone Marrow Collection
<ol>
	<li>Prepare 250 mL complete media by adding a solution of Roswell Park Memorial Institute (RPMI) 1640 medium supplemented with 10% fetal calf serum, 2 mM glutamine, and 50 &#181;M 2-mercaptoethanol to the top...

<ol>
	<li>Zhan, Y., Xu, Y., Lew, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+regulation+of+the+development+and+function+of+dendritic+cell+subsets+by+GM-CSF:+more+than+a+hematopoietic+growth+factor.">The regulation of the development and function of dendritic cell subsets by GM-CSF: more than a hematopoietic growth factor.</a> Mol Immunol. 52, 30-37 (2012).</li><li>Zhan, Y., 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+inflammatory+cytokine,+GM-CSF,+alters+the+developmental+outcome+of+murine+dendritic+cells.">The inflammatory cytokine, GM-CSF, alters the developmental outcome of murine dendritic cells.</a> Eur J Immunol. , (2012).</li><li>van de Laar, L., Coffer, P. J., Woltman, A. 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M., Inaba, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myeloid+dendritic+cells.">Myeloid dendritic cells.</a> J Leukoc Biol. 66, 205-208 (1999).</li><li>Inaba, K., 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> J Exp Med. 176, 1693-1702 (1992).</li><li>Steinman, R. M., Pack, M., Inaba, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendritic+cell+development+and+maturation.">Dendritic cell development and maturation.</a> Adv Exp Med Biol. , 1-6 (1997).</li><li>Pierre, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Developmental+regulation+of+MHC+class+II+transport+in+mouse+dendritic+cells.">Developmental regulation of MHC class II transport in mouse dendritic cells.</a> Nature. 388, 787-792 (1997).</li><li>Steinman, R. M., Witmer-Pack, M., Inaba, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendritic+cells:+antigen+presentation,+accessory+function+and+clinical+relevance.">Dendritic cells: antigen presentation, accessory function and clinical relevance.</a> Adv Exp Med Biol. , 1-9 (1993).</li><li>Na, Y. R., Jung, D., Gu, G. J., Seok, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=GM-CSF+Grown+Bone+Marrow+Derived+Cells+Are+Composed+of+Phenotypically+Different+Dendritic+Cells+and+Macrophages.">GM-CSF Grown Bone Marrow Derived Cells Are Composed of Phenotypically Different Dendritic Cells and Macrophages.</a> Mol Cells. 39, 734-741 (2016).</li><li>Rogers, P. B., Driessnack, M. G., Hiltbold Schwartz, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+the+developmental+stages,+kinetics,+and+phenotypes+exhibited+by+myeloid+cells+driven+by+GM-CSF+in+vitro.">Analysis of the developmental stages, kinetics, and phenotypes exhibited by myeloid cells driven by GM-CSF in vitro.</a> PLoS One. 12, e0181985 (2017).</li><li>Helft, 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=GM-CSF+Mouse+Bone+Marrow+Cultures+Comprise+a+Heterogeneous+Population+of+CD11c(+)MHCII(+)+Macrophages+and+Dendritic+Cells.">GM-CSF Mouse Bone Marrow Cultures Comprise a Heterogeneous Population of CD11c(+)MHCII(+) Macrophages and Dendritic Cells.</a> Immunity. 42, 1197-1211 (2015).</li><li>Alloatti, A., Kotsias, F., Magalhaes, J. G., Amigorena, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendritic+cell+maturation+and+cross-presentation:+timing+matters!.">Dendritic cell maturation and cross-presentation: timing matters!.</a> Immunol Rev. 272, 97-108 (2016).</li><li>Jakubzick, C. V., Randolph, G. J., Henson, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monocyte+differentiation+and+antigen-presenting+functions.">Monocyte differentiation and antigen-presenting functions.</a> Nat Rev Immunol. 17, 349-362 (2017).</li><li>Mbongue, J. C., Nieves, H. A., Torrez, T. W., Langridge, W. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Role+of+Dendritic+Cell+Maturation+in+the+Induction+of+Insulin-Dependent+Diabetes+Mellitus.">The Role of Dendritic Cell Maturation in the Induction of Insulin-Dependent Diabetes Mellitus.</a> Frontiers in immunology. 8, 327 (2017).</li><li>Shortman, K., Naik, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Steady-state+and+inflammatory+dendritic-cell+development.">Steady-state and inflammatory dendritic-cell development.</a> Nat Rev Immunol. 7, 19-30 (2007).</li><li>Xu, Y., Zhan, Y., Lew, A. M., Naik, S. H., Kershaw, M. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+development+of+murine+dendritic+cells+by+GM-CSF+versus+Flt3+ligand+has+implications+for+inflammation+and+trafficking.">Differential development of murine dendritic cells by GM-CSF versus Flt3 ligand has implications for inflammation and trafficking.</a> J Immunol. 179, 7577-7584 (2007).</li><li>Naik, S. H. <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+pro-DCs+and+pre-DCs+in+vitro.">Generation of large numbers of pro-DCs and pre-DCs in vitro.</a> Methods Mol Biol. 595, 177-186 (2010).</li><li>Nikolic, T., de Bruijn, M. F., Lutz, M. B., Leenen, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Developmental+stages+of+myeloid+dendritic+cells+in+mouse+bone+marrow.">Developmental stages of myeloid dendritic cells in mouse bone marrow.</a> Int Immunol. 15, 515-524 (2003).</li><li>Hettinger, 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=Origin+of+monocytes+and+macrophages+in+a+committed+progenitor.">Origin of monocytes and macrophages in a committed progenitor.</a> Nat Immunol. 14, 821-830 (2013).</li><li>Fogg, D. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+clonogenic+bone+marrow+progenitor+specific+for+macrophages+and+dendritic+cells.">A clonogenic bone marrow progenitor specific for macrophages and dendritic cells.</a> Science. 311, 83-87 (2006).</li><li>Traver, 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=Development+of+CD8{alpha}-Positive+Dendritic+Cells+from+a+Common+Myeloid+Progenitor.">Development of CD8{alpha}-Positive Dendritic Cells from a Common Myeloid Progenitor.</a> Science. 290, 2152-2154 (2000).</li></ol>

The authors have no conflicts to disclose.

This protocol facilitates isolation of GM-CSF-driven progenitor and precursor cell types in numbers sufficient for several types of analyses including biochemical assays, assays of cellular function in vitro, or instillation in vivo. This method represents a significant advance in the field of monocyte-derived dendritic cell development, enabling the reliable isolation and identification of cells early in this pathway of development as well as those differentiated cell types more commonly isolated in pr...

Culturing of murine bone marrow cells with the cytokine Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) is widely used as a method to generate monocyte-derived dendritic cells (moDC; also known as inflammatory DC) in large numbers 1,2,3,4,5. These cells have been extremely useful in a variety of studies of dendritic cell (DC) function 6,7,8. Typically, these murine bone marrow cells are cultured for 6-8 days and are then used for study of dendritic cell function 5. These cultures had long been considered mostly homogenous, consisting of a majority of differentiated moDC. More recently, it has become clear that at the end of this 6&#8211;8 day culture period, there are indeed many moDC, as well as a large subset of differentiated monocyte-derived macrophages (moMacs) 9,10,11. Our own studies have further extended these findings demonstrating that other subsets of less developed cells, such as moDC precursors (moDP) and monocytes, remain in the cultures at low frequency even after 7 days 10. Thus, studies of dendritic cells (DC) function using cells generated by this system could reflect the responses of a broader cohort of cell types than previously appreciated.
We have learned a great deal from the study of GM-CSF-generated moDC relating to the function of these cells in the final stages of differentiation&#160;12,13,14. However, we understand significantly less about the developmental pathway of these cells&#160;2,15,16 and of how and when they exhibit specific functions such as: responsiveness to Pathogen Associated Molecular Patterns (PAMPs), phagocytosis, antigen processing and presentation&#160;13, and anti-bacterial activity. A protocol for isolation of large numbers of conventional Flt3L-driven DC progenitors and precursors has been reported&#160;17. Isolation of these distinct populations was achieved using carboxyfluorescein succinimidyl ester (CFSE)-stained bone marrow cells (to track dividing cells) and culture in Flt3L for 3 days. Cells were then depleted of linage positive cells and sorted into progenitor and precursor populations based on CD11c expression&#160;17. Another approach by Leenen&#39;s group to identify early progenitors of DC in GM-CSF-driven culture was to sort cells based on CD31 and Ly6C 18. The initial goal was to create a similar method for obtaining progenitors and precursors of GM-CSF-driven moDC. Due to the specific cell types generated by GM-CSF, we adapted the approach and sorting strategy based on expression of molecules that were expressed at early and later stages of development. We ultimately determined that Ly6C, CD115 (CSF-1 receptor), and CD11c were the best markers for distinguishing these cell types&#160;10.
Here, we present a method for isolation of cells at several distinct stages of development along the pathway of differentiation driven by GM-CSF: Common Myeloid Progenitor (CMP), Granulocyte-Macrophage Progenitor (GMP), monocyte, monocyte-derived Macrophage (MoMac) and monocyte-derived DC (MoDC). The moMac population can be further segregated based on level of MHC class II expression, revealing a moDC precursor population (moDP)&#160;10. We utilize a high-speed fluorescence-activated cell sorting (FACS) strategy to isolate these 5 populations based on expression of Ly6C, CD115, and CD11c. We then demonstrate the examination of these cells in functional assays revealing their responses to PAMP stimulation.

<table>
	<tbody>
		<tr>
			<td>RPMI 1640</td>
			<td>Corning</td>
			<td>15-040-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Calf Serum (FCS)</td>
			<td>HyClone</td>
			<td>SV30014.04</td>
			<td>to supplement complete medium and FWB</td>
		</tr>
		<tr>
			<td>GlutaMAX</td>
			<td>Gibco</td>
			<td>35050</td>
			<td>to supplement complete medium</td>
		</tr>
		<tr>
			<td>2-mercaptoethanol (2-ME)</td>
			<td>MP Biomedical</td>
			<td>190242</td>
			<td>to supplement complete medium</td>
		</tr>
		<tr>
			<td>75mM Vacuum Filter</td>
			<td>Thermo Scientific</td>
			<td>156-4045</td>
			<td>to sterilize complete media</td>
		</tr>
		<tr>
			<td>ACK Lysis Buffer</td>
			<td>Lonza</td>
			<td>10-548E</td>
			<td>to lyse red blood cell</td>
		</tr>
		<tr>
			<td>HEPES buffer</td>
			<td>Corning</td>
			<td>21-020-CM</td>
			<td>to rescue leukocytes after red blood cell lysis</td>
		</tr>
		<tr>
			<td>Phosphate Buffered Saline (PBS), Dulbecco&#39;s</td>
			<td>Lonza</td>
			<td>17-512F</td>
			<td>must be endotoxin free; chilled at 4 &#176;C</td>
		</tr>
		<tr>
			<td>35&#181;m Cell filter</td>
			<td>Falcon</td>
			<td>352235</td>
			<td>to break apart clumps before running through cytometer.</td>
		</tr>
		<tr>
			<td>GM-CSF</td>
			<td>Biosource</td>
			<td>PMC2011</td>
			<td>usable concentration of 10ng/mL</td>
		</tr>
		<tr>
			<td>Tissue cultured treated plate</td>
			<td>VWR</td>
			<td>10062-896</td>
			<td>for bone marrow cells after harvest</td>
		</tr>
		<tr>
			<td>Anti-Ly6C, Clone HK1.4</td>
			<td>Biolegend</td>
			<td>128018</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-CD115, Clone AFS98</td>
			<td>Tonbo Bioscience</td>
			<td>20-1152-U100</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-CD11c, Clone HL3</td>
			<td>BD Biosciences</td>
			<td>557400</td>
			<td>to differeniate CMP and MoDCs</td>
		</tr>
		<tr>
			<td>MoFlo XPD Flow Cytometer</td>
			<td>Beckman Coulter</td>
			<td>ML99030</td>
			<td></td>
		</tr>
		<tr>
			<td>BD Accuri C6</td>
			<td>BD Biosciences</td>
			<td>660517</td>
			<td></td>
		</tr>
		<tr>
			<td>100% Ethanol</td>
			<td>Pharmco-Aaper</td>
			<td>111000200CSPP</td>
			<td></td>
		</tr>
		<tr>
			<td>60mm Petri Dish</td>
			<td>Corning, Inc</td>
			<td>353002</td>
			<td></td>
		</tr>
		<tr>
			<td>50mL Conical tube</td>
			<td>VWR</td>
			<td>21008-242</td>
			<td></td>
		</tr>
		<tr>
			<td>C57BL/6 Mice</td>
			<td>The Jackson Laboratory</td>
			<td>000664</td>
			<td>Female; 10-20 weeks old</td>
		</tr>
		<tr>
			<td>Biosafety Hood</td>
			<td>Thermo Scientific</td>
			<td>8354-30-0011</td>
			<td></td>
		</tr>
		<tr>
			<td>10mL Syringe</td>
			<td>BD Biosciences</td>
			<td>301604</td>
			<td></td>
		</tr>
		<tr>
			<td>23-gauge needle</td>
			<td>BD Biosciences</td>
			<td>305145</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge 5810&#160;R</td>
			<td>eppendorf</td>
			<td>22625501</td>
			<td></td>
		</tr>
		<tr>
			<td>FlowJo Software v10</td>
			<td>BD Biosciences</td>
			<td>Version 10</td>
			<td>flowjo.com</td>
		</tr>
	</tbody>
</table>

generation of large numbers of myeloid progenitors and dendritic cell precursors from murine bone marrow using a novel cell sorting strategy

Cultures of monocyte-derived dendritic cells (moDC) generated from mouse bone marrow using Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) have recently been recognized to be more heterogeneous than previously appreciated. These cultures routinely contain moDC as well monocyte-derived macrophages (moMac), and even some less developed cells such as monocytes. The goal of this protocol is to provide a consistent method for identification and separation of the many cell types present in these cultures as they develop, so that their specific functions may be further investigated. The sorting strategy presented here separates cells first into four populations based on expression of Ly6C and CD115, both of which are expressed transiently by cells as they develop in GM-CSF-driven culture. These four populations include Common myeloid progenitors or CMP (Ly6C-, CD115-), granulocyte/macrophage progenitors or GMP (Ly6C+, CD115-), monocytes (Ly6C+, CD115+), and monocyte-derived macrophages or moMac (Ly6C-, CD115+). CD11c is also added to the sorting strategy to distinguish two populations within the Ly6C-, CD115- population: CMP (CD11c-) and moDC (CD11c+). Finally, two populations may be further distinguished within the Ly6C-, CD115+ population based on the level of MHC class II expression. MoMacs express lower levels of MHC class II, while a monocyte-derived DC precursor (moDP) expresses higher MHC class II. This method allows for the reliable isolation of several developmentally distinct populations in numbers sufficient for a variety of functional and developmental analyses. We highlight one such functional readout, the differential responses of these cell types to stimulation with Pathogen-Associated Molecular Patterns (PAMPs).

In an effort to keep as many channels available for analysis as possible, viable cells were routinely selected based on forward and side scatter, excluding very small and very granular events (a typical gate is applied to all the dot plots in Figure 1A). To determine if this gating strategy reliably excluded dead cells, we stained with 7-Amino actinomycin D (7-AAD) (Figure 1B). 7AAD stains DNA in dead and dying cells due to membr...

Watch this Scientific Journal Video about Generation of Large Numbers of Myeloid Progenitors and Dendritic Cell Precursors from Murine Bone Marrow Using a Novel Cell Sorting Strategy at JoVE.com

Generation of Large Numbers of Myeloid Progenitors and Dendritic Cell Precursors from Murine Bone Marrow Using a Novel Cell Sorting Strategy

Here we provide a method for identifying and isolating large numbers of GM-CSF driven myeloid cells using high speed cell sorting. Five distinct populations (Common myeloid progenitors, granulocyte/macrophage progenitors, monocytes, monocyte-derived macrophages, and monocyte-derived DCs) can be identified based on Ly6C and CD115 expression.

Cultures of monocyte-derived dendritic cells (moDC) generated from mouse bone marrow using Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) have ...

This method can enable researchers to acquire sufficient numbers of cell types to answer key questions in the field of developmental immunology. The main advantage of this technique is that it relies on a few select markers to isolate large numbers of cells that are traditionally found in low numbers ex vivo. The implication of this technique extends towards the therapeutic bone marrow transplantation, because it allows for the isolation of large numbers of progenitors.To begin the protocol, saturate the hind legs and torso of a previously prepared mouse with 75%ethanol, and make shallow cuts through the skin around the hip joint with curved tissue scissors. Then, remove and strip the hind legs. Using forceps, firmly pull the skin from the hip down towards the ankle, revealing the muscle, and use scissors to remove the skin flap.Cut just above the femur and hip joint, and remove the whole hind leg by cutting through the bone. Working in a sterile biosafety cabinet, transfer the legs to one of the previously-prepared petri dishes. Use scissors to cut just below the ankle, and carefully remove as much of the muscle and elastic connective tissue as possible.Transfer the cleaned bone to the second prepared petri dish. Next, separate the femur, knee, and tibia. Using forceps, hold the leg at the knee and locate the marrow, a faint red line inside the bone cavity at the top of the femur and toward the end of the tibia.With scissors, cut the tibia just above where the marrow appears to end. Cut just below the knee joint, cut just above the knee joint. Then, flush bone marrow from the femur and tibia.Fill a 10 milliliter syringe with complete media from the 50 milliliter conical tube, and cap the syringe with a 23 gauge needle. Holding the bone with forceps above the third prepared petri dish, insert the needle into the bone canal, and push the media through, flushing out the cells. Repeat this step until no more color can be seen through the bone.Continue the procedure by crushing the epiphysis. While still in the second petri dish, hold the kneecap firmly with forceps, and mash the knees with the tip of the syringe. Continue until the epiphysis are no longer red.Using the syringe, transfer the cells from the second and third petri dishes to the 50 milliliter tube. Break up clumps by gently pipetting up and down, and try to avoid forming bubbles. Centrifuge the cells.Then remove the supernatant with the serological pipette, dislodge the pellet by flicking, and lyse red blood cells by incubating them in one milliliter of ammonium chloride potassium or ACK lysis buffer, for one minute at room temperature. Using a serological pipette, add 40 milliliters of HBSS buffer. Using a serological pipette, filter the cells through a 70 micrometer cell strainer into a new 50 milliliter conical tube, and centrifuge the cells.Using a serological pipette, remove the supernatant and culture the bone marrow cells in complete media with 10 nanograms per milliliter of Recombinant Mouse GM-CSF at a density of one times 10 to the 6th cells per milliliter. Using a serological pipette, transfer the cells to tissue culture plates, and incubate them at 37 degrees Celsius in 5%carbon dioxide, until ready to proceed with staining. Gently, but thoroughly, pipette the cells up and down to dislodge loosely adherent cells.Using a serological pipette, transfer cells to a 50 milliliter conical tube, and centrifuge the cells. Gently pour off the supernatant, and wash the pelleted cells by adding 30 milliliters of FACS wash buffer, or SFWB, with the serological pipette. Then centrifuge the cells and repeat the wash.Next, suspend and stain cells per the antibody manufacturer's instructions. Resuspend five times 10 to the 7th cells in one milliliter of FWB, and add two micrograms each of anti Ly-6C, and anti CD115, labeled with fluorophores. To further distinguish CMP from MODC, add two micrograms of anti CD11C antibodies.Incubate the samples for 30 minutes on ice. After incubation, use a serological pipette to add 10 milliliters of FWB, and centrifuge the cells. Gently pour off the supernatant, and wash the pelleted cells by adding 30 milliliters of FWB with a serological pipette.Centrifuge the cells, and repeat the wash. Before suspending the cells, flick the tube thoroughly to dislodge the pellet. Use a serological pipette to resuspend cells at one times 10 to the 7th cells per milliliter of FWB, and filter them through a 35 micrometer cell filter.Use a serological pipette to transfer the filtered cells into a polypropelyne tube, and place the tube on ice until they are ready to be sorted. Run the unstained control through the cell sorter, and apply a gate to exclude small debris and highly granular particles. Run the single fluorescent control samples through the cell sorter, and adjust the compensation as needed.Run a sample of the multi-labeled sample, and observe four distinct populations. Apply a gate to isolate each of the four major populations. Prepare collection tubes by adding enough fetal calf serum, or FCS, to achieve at least 20%final concentration when full.For example, if using five milliliter tubes, add one milliliter of FCS before sorting, and remove the tube when it reaches five milliliters total volume. To prevent membrane turnover and antibody uptake, keep all samples at four degrees Celsius throughout the sort. After the desired number of cells have been collected, use a serological pipette to transfer the cells to a new conical tube, and centrifuge the cells.Carefully remove the supernatant and resuspend the cells in 10 milliliters of FWB, and centrifuge the cells again. Repeat the FWB suspension for a total of two washes. Finally, remove the supernatant after the second wash, and proceed based on the experiment's design.To keep as many channels available for analysis as possible, viable cells were routinely selected, based on forward and side scatter, excluding very small and very granular events. To determine if this gating strategy reliably excluded dead cells, samples were stained with 7-Aminoactinomycin D.Cells analyzed immediately post harvest had approximately 10%of 7-AAD positive cells, when a typical FSC, SSC gate was applied to freshly isolated cells from the bone marrow. A similar proportion of dead cells was also present at stay 1 and stay 3 of culture.By day five, the number of dead cells within the gate was reduced to 5%thus, using such a viability gate is generally appropriate for sorting on day five and after. Flow cytometry revealed that within the Ly6C negative, CD115 population, CD3, CD45R positive cells persisted strongly through day zero through three. On day four, only a few CD3, CD45R positive cells remained, and by day five and six, there were no CD3, CD45R expressing cells present;thus, within four days of culture in GM-CSF, lineage positive cells were essentially absent, and were not detected at all at days five and six of culture.While attempting this procedure, it's important to remember cellular composition is dependent on the length of culture. Sorting three days post-harvest yields high numbers of early stages and few late stage, and vice-versa for cultures sorted after five days.

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Immunology and Infection

9.0K Görüntüleme.  Auburn University. This method can enable researchers to acquire sufficient numbers of cell types to answer key questions in the field of developmental immunology. The main advantage of this technique is that it relies on a few select markers to isolate large numbers of cells that are traditionally found in low numbers ex vivo. The implication of this technique extends towards the therapeutic bone marrow transplantation, because it allows for the isolation of large numbers of progenitors.To begin the pro...