We would like to thank the LJI Flow Cytometry core for assistance with mass cytometry procedure. This work was supported by NIH grants R01HL134236, P01HL136275, and R01CA202987 (all to C.C.H) and ADA7-12-MN-31 (04) (to C.C.H. and Y.P.Z).

All experiments followed approved guidelines of the La Jolla Institute for Allergy and Immunology Animal Care and Use Committee, and approval for the use of rodents was obtained from the La Jolla Institute for Allergy and Immunology according to criteria outlined in the Guide for the Care and Use of Laboratory Animals from the National Institutes of Health.
1. Harvest Mouse Bone Marrow (BM)
<ol>
	<li>Purchase C57BL/6J mice from a commercial vendor. Feed the standard rodent chow diet and hous...

<ol>
	<li>Akashi, K., Traver, D., Miyamoto, T., Weissman, I. L. <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+common+myeloid+progenitor+that+gives+rise+to+all+myeloid+lineages.">A clonogenic common myeloid progenitor that gives rise to all myeloid lineages.</a> Nature. 404, 193-197 (2000).</li><li>Iwasaki, H., Akashi, 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+lineage+commitment+from+the+hematopoietic+stem+cell.">Myeloid lineage commitment from the hematopoietic stem cell.</a> Immunity. 26, 726-740 (2007).</li><li>Manz, M. G., Miyamoto, T., Akashi, K., Weissman, I. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prospective+isolation+of+human+clonogenic+common+myeloid+progenitors.">Prospective isolation of human clonogenic common myeloid progenitors.</a> Proceedings of the National Academy of Sciences. 99, 11872-11877 (2002).</li><li>Becher, 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=High-dimensional+analysis+of+the+murine+myeloid+cell+system.">High-dimensional analysis of the murine myeloid cell system.</a> Nature Immunology. 15, 1181-1189 (2014).</li><li>Bendall, S. C., 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=Single-cell+mass+cytometry+of+differential+immune+and+drug+responses+across+a+human+hematopoietic+continuum.">Single-cell mass cytometry of differential immune and drug responses across a human hematopoietic continuum.</a> Science. 332, 687-696 (2011).</li><li>Samusik, N., Good, Z., Spitzer, M. H., Davis, K. L., Nolan, G. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+mapping+of+phenotype+space+with+single-cell+data.">Automated mapping of phenotype space with single-cell data.</a> Nature Methods. 13, 493-496 (2016).</li><li>Zhu, Y. 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=Identification+of+an+Early+Unipotent+Neutrophil+Progenitor+with+Pro-tumoral+Activity+in+Mouse+and+Human+Bone+Marrow.">Identification of an Early Unipotent Neutrophil Progenitor with Pro-tumoral Activity in Mouse and Human Bone Marrow.</a> Cell Reports. 24, 2329-2341 (2018).</li><li>Van der Maaten, L. J. P., Hinton, G. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualizing+High-Dimensional+Data+Using+t-SNE.">Visualizing High-Dimensional Data Using t-SNE.</a> Journal of Machine Learning Research. 9, 2579-2605 (2008).</li><li>Amir, E. A. 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=viSNE+enables+visualization+of+high+dimensional+single-cell+data+and+reveals+phenotypic+heterogeneity+of+leukemia.">viSNE enables visualization of high dimensional single-cell data and reveals phenotypic heterogeneity of leukemia.</a> Nature Biotechnology. 31, 545-552 (2013).</li><li>van der Maaten, L., Hinton, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualizing+data+using+t-SNE.">Visualizing data using t-SNE.</a> Journal of Machine Learning Research. 9 (85), 2579-2065 (2008).</li><li>Cloos, 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=Comprehensive+Protocol+to+Sample+and+Process+Bone+Marrow+for+Measuring+Measurable+Residual+Disease+and+Leukemic+Stem+Cells+in+Acute+Myeloid+Leukemia.">Comprehensive Protocol to Sample and Process Bone Marrow for Measuring Measurable Residual Disease and Leukemic Stem Cells in Acute Myeloid Leukemia.</a> Journal of Visualized Experiment. 133, 56386 (2018).</li><li>Bendall, S. C., Nolan, G. P., Roederer, M., Chattopadhyay, P. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+deep+profiler&#8217;s+guide+to+cytometry.">A deep profiler&#8217;s guide to cytometry.</a> Trends in Immunology. 33, 323-332 (2012).</li><li>Ley, 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=Neutrophils:+New+insights+and+open+questions.">Neutrophils: New insights and open questions.</a> Science Immunology. 3 (30), 4579 (2018).</li><li>Ng, L. G., Ostuni, R., Hidalgo, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterogeneity+of+neutrophils.">Heterogeneity of neutrophils.</a> Nature Reviews in Immunology. , (2019).</li></ol>

The authors have nothing to disclose.

In past decades, fluorescence-based flow cytometry was used as the main method to study cellular lineages and heterogeneity1,2,3. Although flow cytometry has provided multi-dimensional data, this method is limited by choices of parameters and spectral overlap. To overcome the weakness of flow cytometry we took advantage of CyTOF, which uses heavy metal isotopes instead of fluorophores to label antibodies that eliminates crosstal...

In the past few decades, cytometry methods have been a powerful tool to investigate the hematopoietic system in the BM. These methods include fluorescence-activated flow cytometry and the new method of CyTOF using heavy metal-labeled antibodies. They have led to discoveries of many cell types in a heterogeneous biological specimen by identification of their unique surface marker expression profiles. Increased spectrum overlaps that&#8217;s associated with more channels leads to higher data inaccuracy in fluorescence-activated flow cytometry applications. Therefore, unwanted cells are routinely removed in order to enrich cell populations of interest for fluorescence-activated flow cytometry analysis. For example, Ly6G (or Gr-1) and CD11b are considered mature myeloid cell markers and Ly6G+ (or Gr-1+) and CD11b+ cells are routinely removed from BM samples by using magnetic enrichment kits prior to flow cytometry analysis of hematopoietic stem and progenitor cells (HSPCs) or by combining these markers in one dump cocktail channel1,2,3. Another example is that neutrophils are routinely removed from human blood specimen to enrich peripheral blood mononuclear cells (PBMC) for immunological studies. Whole bone marrow isolated from mouse or human, however, is rarely investigated intact for cytometry analysis.
Recently, CyTOF has become a revolutionary tool to investigate the hematopoietic system4,5,6. With CyTOF, the fluorophore-labeled antibodies are replaced by heavy element reporter-labeled antibodies. This method allows for the measurement of over 40 markers simultaneously without the concern of spectrum overlap. It has enabled the analysis of intact biological specimen without pre-depletion steps or a dump channel. Therefore, we can view the hematopoietic system comprehensively with high-content dimensionality from conventional 2-D flow cytometry plots. Cell populations omitted in the past during depletion or gating process can now be brought into light with the high-dimensional data generated by CyTOF4,5. We have designed an antibody panel that simultaneously measures 39 parameters in the hematopoietic system with a focus on the myeloid linage7. Compared to the conventional flow cytometry data, the interpretation and visualization of the unprecedented single-cell high-dimensional data generated by CyTOF is challenging. Computational scientists have developed dimensionality reduction techniques for the visualization of high-dimensional datasets. In this article, we used the algorithm, viSNE, which uses t-Distributed Stochastic Neighbor Embedding (t-SNE) technique to analyze the CyTOF data and to present the high-dimensional result on a 2-dimensional map while conserving the high-dimensional structure of the data8,9,10. On the tSNE plot, similar cells are clustered into subsets and the color is used to highlight the feature of the cells. For example, on Figure 1 the myeloid cells are distributed into several cell subsets based on the similarities of their expression patterns of 33 surface markers resulted from CyTOF (Figure 1)4. Here we investigated mouse bone marrow with our previously reported 39-marker CyTOF panel by viSNE analysis7. viSNE analysis of our CyTOF data revealed an unidentified cell population that showed both HSPC (CD117+) and neutrophil (Ly6G+) characteristics (Figure 2)7.
In conclusion, we present a protocol to process fresh whole bone marrow for CyTOF analysis. In this article, we used mouse bone marrow as an example, while this protocol can also be used to process human bone marrow samples. The details specific to human bone marrow samples are also noted in the protocol as well. The advantage of this protocol is that it contains details such as incubation time and temperature that were optimized to preserve neutrophil-lineage cells in the whole bone marrow to enable investigation on the intact whole bone marrow. This protocol may also be easily modified for fluorescence-activated flow cytometry applications.

<table>
	<tbody>
		<tr>
			<td>CyTOF Antibodies (mouse)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse CD45 (Clone 30-F11) -89Y</td>
			<td>Fluidigm</td>
			<td>Cat# 3089005B</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Human/Mouse CD45R/B220 (Clone RA36B2)-176Yb</td>
			<td>Fluidigm</td>
			<td>Cat# 3176002B</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD105 (Clone MJ7/18)-Purified</td>
			<td>Biolegend</td>
			<td>Cat# 120402; RRID:AB_961070</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD115 (CSF-1R) (Clone AFS98)-Purified</td>
			<td>Biolegend</td>
			<td>Cat# 135502; RRID:AB_1937293</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse CD117/c-kit (Clone 2B8)-166Er</td>
			<td>Fluidigm</td>
			<td>Cat# 3166004B</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD11a (Clone M17/4)-Purified</td>
			<td>Biolegend</td>
			<td>Cat# 101101; RRID:AB_312774</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse CD11b (Clone M1/70)-148Nd</td>
			<td>Fluidigm</td>
			<td>Cat# 3148003B</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse CD11c (Clone N418)-142Nd</td>
			<td>Fluidigm</td>
			<td>Cat# 3142003B</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD127 (IL-7R&#945;) (Clone A7R34)-MaxPar Ready</td>
			<td>Biolegend</td>
			<td>Cat# 133919; RRID:AB_2565433</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse CD150 (Clone TC1512F12.2)-167Er</td>
			<td>Fluidigm</td>
			<td>Cat# 3167004B</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD16.2 (Fc&#947;RIV) (Clone 9E9)-Purified</td>
			<td>Biolegend</td>
			<td>Cat# 149502; RRID:AB_2565302</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse CD162 (Clone 4RA10 (RUO))-Purified</td>
			<td>BD Biosciences</td>
			<td>Cat# 557787; RRID:AB_647340</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD169 (Siglec-1) (Clone 3D6.112)-Purified</td>
			<td>Biolegend</td>
			<td>Cat# 142402; RRID:AB_10916523</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD182 (CXCR2) (Clone SA044G4)-Purified</td>
			<td>Biolegend</td>
			<td>Cat# 149302; RRID:AB_2565277</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD183 (Clone CXCR3-173)-Purified</td>
			<td>Biolegend</td>
			<td>Cat# 126502; RRID:AB_1027635</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD335 (NKp46) (Clone 29A1.4)-MaxPar Ready</td>
			<td>Biolegend</td>
			<td>Cat# 137625; RRID:AB_2563744</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD34 (Clone MEC14.7)-Purified</td>
			<td>Biolegend</td>
			<td>Cat# 119302; RRID:AB_345280</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD41 (Clone MWReg30)-MaxPar Ready</td>
			<td>Biolegend</td>
			<td>Cat# 133919; RRID:AB_2565433</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse CD43 (Clone S11)-146Nd</td>
			<td>Fluidigm</td>
			<td>Cat# 3146009B</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse CD48 (Clone HM48.1)-156Gd</td>
			<td>Fluidigm</td>
			<td>Cat# 3156012B</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD62L (Clone MEL-14)-MaxPar Ready</td>
			<td>ThermoFisher</td>
			<td>Cat# 14-1351-82; RRID:AB_467481</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD71 (Clone RI7217)-Purified</td>
			<td>Biolegend</td>
			<td>Cat# 113802; RRID:AB_313563</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse CD90 (Clone G7)-Purified</td>
			<td>Biolegend</td>
			<td>Cat# 105202; RRID:AB_313169</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse F4/80 (Clone BM8)-159Tb</td>
			<td>Fluidigm</td>
			<td>Cat# 3159009B</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse Fc&#949;RI&#945; (Clone MAR-1)-MaxPar Ready</td>
			<td>Biolegend</td>
			<td>Cat# 134321; RRID:AB_2563768</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse GM-CSF (MP1-22E9 (RUO))-Purified</td>
			<td>BD Biosciences</td>
			<td>Cat# 554404; RRID:AB_395370</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse I-A/I-E (Clone M5/114.15.2)-174Yb</td>
			<td>Fluidigm</td>
			<td>Cat# 3174003B</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse Ki67 (Clone B56 (RUO))-Purified</td>
			<td>BD Biosciences</td>
			<td>Cat# 556003; RRID:AB_396287</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse Ly-6A/E (Sca-1) (Clone D7)-169Tm</td>
			<td>Fluidigm</td>
			<td>Cat# 3169015B</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse Ly6B (Clone 7/4)-Purified</td>
			<td>abcam</td>
			<td>Cat# ab53457; RRID:AB_881409</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse Ly-6G (Clone 1A8)-MaxPar Ready</td>
			<td>Biolegend</td>
			<td>Cat# 127637; RRID:AB_2563784</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse NK1.1 (Clone PK136)-165Ho</td>
			<td>Fluidigm</td>
			<td>Cat# 3165018B</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse Siglec-F (Clone E50-2440 (RUO))-Purified</td>
			<td>BD Biosciences</td>
			<td>Cat# 552125; RRID:AB_394340</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Mouse TCR&#946; (Clone H57-597)-143Nd</td>
			<td>Fluidigm</td>
			<td>(Clone H57-597)-143Nd</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse TER-119/Erythroid Cells (Clone TER-119)-MaxPar Ready</td>
			<td>Biolegend</td>
			<td>Cat# 116241; RRID:AB_2563789</td>
			<td></td>
		</tr>
		<tr>
			<td>Chemicals, Peptides and Recombinant Proteins </td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Antibody Stabilizer</td>
			<td>CANDOR Bioscience</td>
			<td>Cat# 130050</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin</td>
			<td>Sigma-Aldrich</td>
			<td>Cat# A4503</td>
			<td></td>
		</tr>
		<tr>
			<td>Cisplatin-194Pt</td>
			<td>Fluidigm</td>
			<td>Cat# 201194</td>
			<td></td>
		</tr>
		<tr>
			<td>eBioscience 1X RBC Lysis Buffer</td>
			<td>ThermoFisher</td>
			<td>Cat# 00-4333-57</td>
			<td></td>
		</tr>
		<tr>
			<td>eBioscience Foxp3 / Transcription Factor Staining Buffer Set</td>
			<td>ThermoFisher</td>
			<td>Cat# 00-4333-57</td>
			<td></td>
		</tr>
		<tr>
			<td>EQ Four Element Calibration Beads</td>
			<td>Fluidigm</td>
			<td>Cat# 201078</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethylenediaminetetraacetic acid (EDTA)</td>
			<td>ThermoFisher</td>
			<td>Cat# AM9260G</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Omega Scientific</td>
			<td>Cat# FB-02</td>
			<td></td>
		</tr>
		<tr>
			<td>HyClone Phosphate Buffered Saline solution</td>
			<td>GE Lifesciences</td>
			<td>Cat#SH30256.01</td>
			<td></td>
		</tr>
		<tr>
			<td>Intercalator-Ir</td>
			<td>Fluidigm</td>
			<td>Cat# 201192B</td>
			<td></td>
		</tr>
		<tr>
			<td>MAXPAR Antibody Labeling Kits</td>
			<td>Fluidigm</td>
			<td>http://www.dvssciences.com/product-catalog-maxpar.php</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>Cat# 158127</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium azide</td>
			<td>Sigma-Aldrich</td>
			<td>Cat# S2002</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton&#160;X-100</td>
			<td>Sigma-Aldrich</td>
			<td>Cat# X100</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin EDTA 1X</td>
			<td>Corning</td>
			<td>Cat# 25-053-Cl</td>
			<td></td>
		</tr>
		<tr>
			<td>Experimental Model: Organism/Strains</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse: C57BL/6J</td>
			<td>The Jackson Laboratory</td>
			<td>Stock No: 000664</td>
			<td></td>
		</tr>
		<tr>
			<td>Software Alogrithm</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bead-based Normalizer</td>
			<td>Finck et al., 2013</td>
			<td>https://med.virginia.edu/flow-cytometry-facility/wp-content/uploads/sites/170/2015/10/3_Finck-Rachel_CUGM_May2013.pdf</td>
			<td></td>
		</tr>
		<tr>
			<td>Cytobank</td>
			<td>Cytobank</td>
			<td>https://www.cytobank.org/</td>
			<td></td>
		</tr>
		<tr>
			<td>Cytofkit v1.r.0</td>
			<td>Chen et al., 2016</td>
			<td>https://bioconductor.org/packages/release/bioc/html/cytofkit.html</td>
			<td></td>
		</tr>
		<tr>
			<td>t-SNE</td>
			<td>van der Maaten and Hinton, 2008</td>
			<td>https://cran.r-project.org/web/packages/Rtsne/index.html</td>
			<td></td>
		</tr>
		<tr>
		</tr>
	</tbody>
</table>

preparation of whole bone marrow for mass cytometry analysis of neutrophil-lineage cells

In this article, we present a protocol that is optimized to preserve neutrophil-lineage cells in fresh BM for whole BM CyTOF analysis. We utilized a myeloid-biased 39-antibody CyTOF panel to evaluate the hematopoietic system with a focus on the neutrophil-lineage cells by using this protocol. The CyTOF result was analyzed with an open-resource dimensional reduction algorithm, viSNE, and the data was presented to demonstrate the outcome of this protocol. We have discovered new neutrophil-lineage cell populations based on this protocol. This protocol of fresh whole BM preparation may be used for 1), CyTOF analysis to discover unidentified cell populations from whole BM, 2), investigating whole BM defects for patients with blood disorders such as leukemia, 3), assisting optimization of fluorescence-activated flow cytometry protocols that utilize fresh whole BM.

Figure 1 is presented as an example result from CyTOF experiments. On this tSNE plot the cells across multiple mouse tissues were clustered into subsets based on the similarity of their surface marker expression profiles measured by a 33-parameter CyTOF panel. Cells with more similar properties were automatically clustered together such as the neutrophils, macrophages, or the DCs based on the expression of the 33 markers on each cell.
Figure 2...

Watch this Scientific Journal Video about Preparation of Whole Bone Marrow for Mass Cytometry Analysis of Neutrophil-lineage Cells at JoVE.com

Preparation of Whole Bone Marrow for Mass Cytometry Analysis of Neutrophil-lineage Cells

Here, we present a protocol to process fresh bone marrow (BM) isolated from mouse or human for high-dimensional mass cytometry (Cytometry by Time-Of-Flight, CyTOF) analysis of neutrophil-lineage cells.

In this article, we present a protocol that is optimized to preserve neutrophil-lineage cells in fresh BM for whole BM CyTOF analysis. We utilized a ...

This mass cytometry protocol preserves the integrity of the whole bone marrow, allowing rescue of the information that was lost during conventional sample preparation for analysis of under studied cells. This fast and effortless bone marrow isolation protocol facilitates the acquisition of viable short-lived myeloid cell populations such as rare neutrophil-lineage subsets. Using mass cytometry to identify previously under appreciated immune cells such as neutrophil-lineage cells may have broad implications for a wide variety of diseases.This protocol preserves the integrity of the short lived myeloid cells that are present in the bone marrow and can easily be applied to other tissue types such as the solid tumor. We simplified to protocol to make it as user friendly as possible, but as in all biological studies it may need a few practice runs to manage. When you're doing this the first time, you can get all your reagents ready first and then strictly follow the protocol.If you do experience any issues, you can connect to the CyTOForum and talk to other CyTOF users who can help troubleshoot. For biological sample preparation, simple tricks can make a huge difference with the end result. A visual demonstration is much easier for a new user to grasp the protocol.If you are doing this for the first time, you can get your reagents ready first and then strictly follow the protocol. For bone marrow harvest, place a six to 10 week old C57 black six mouse in the supine position on a sterile surgical pad and use 70%ethanol to sterilize the abdomen and hind limbs. Use a pair of dissecting surgical scissors to open the abdominal cavity and remove the skin to expose the hind limbs.Using a pair of blunt tipped dressing forceps, hold the mouse tibia right below the ankle and use a pair of curved dressing forceps to stabilize the tibia below the blunt tipped dressing forceps. Use the blunt tipped dressing forceps to break the tibia and remove the muscle to expose the bone. Before placing the tibia in cold PBS, move the stabilizing curved dressing forceps to the femur and slide the blunt tipped dressing forceps below the knee joint to hold the kneecap.Gently pull up to dislocate the kneecap and remove the muscle from the kneecap to expose the femur. Hold the exposed femur by the curved dressing forceps and use surgical scissors to cut the femur from the bottom of the bone. Then place the femur in PBS.Next, use an 18 gauge needle to punch a hole in a 0.5 milliliter micro centrifuge tube and place both bones in the tube with the open ends of the bones facing downward into the hole. Place the 0.5 milliliter tube into a 1.7 milliliter micro centrifuge tube and spin the double layered tubes in a micro centrifuge. At the end of the centrifugation, confirm that the bone marrow has been extracted to the bottom of the tube.To stain the bone marrow cells for mass cytometry, re suspend the bone marrow in one milliliter of red blood cell lysis buffer for 10 minutes at room temperature. At the end of the incubation, collect the cells by centrifugation and re suspend the pellet in one milliliter of cold PBS. Filter the cells through a 70 micrometer strainer into a 15 milliliter conical tube and wash the cells with nine milliliters of fresh, cold PBS.Re suspend the bone marrow cell pellet in 10 milliliters of fresh, cold PBS for counting and transfer a five times 10 to the sixth cell aliquot into a new 15 milliliter tube. Collect the cells by centrifugation and re suspend the cells in one milliliter of mass cytometry staining buffer, supplemented with 125 nanomolar cisplatin. After five minutes at room temperature, wash the cells in four milliliters of fresh mass cytometry buffer.Re suspend the pellet in 50 microliters of FC receptor blocking solution. After 10 minutes at four degrees Celsius, add 50 microliters of the antibody cocktail of interest to the cells and gently pipet to mix. The temperature in different incubation steps are very important in preserving the viability of the bone marrow cells.After 30 minutes at four degrees Celsius, wash the cells two times in two milliliters of fresh mass cytometry buffer per wash before re suspending the cells in one milliliter of freshly prepared 1.6%formaldehyde for 15 minutes at room temperature. At the end of the incubation, collect the cells by centrifugation and re suspend the pellet in one milliliter of fixed perm buffer supplemented with 125 nanomolar intercalation solution for an overnight incubation at four degrees Celsius. Before analyzing the cells by mass cytometry, gently vortex and centrifuge the cell suspension before washing the cells in two milliliters of fresh mass cytometry staining buffer.Next, wash the cells two times in one milliliter of distilled water per wash, carefully aspirating the supernatant after the second wash before re suspending the cells at a one times 10 to the sixth cells per milliliter of mass cytometry buffer concentration for mass cytometry analysis. In this T distributed stochastic neighbor embedding plot, the cells across multiple mouse tissues were clustered into subsets based on the similarity of their surface marker expression profiles as measured by a 33 parameter mass cytometry panel. Cells with more similar properties were automatically clustered together based on the expression of these markers on each cell.Using this method, the integrity of the whole bone marrow was preserved, leading to the discovery of a previously unknown cell population that simultaneously co-expresses neutrophil and hematopoietic stem and progenitor cells signature surface markers. This cell population, which was previously omitted in myeloid progenitor studies, due to Ly6G positive cell depletion, exhibits a distinct pattern of surface marker expression. More importantly, these data led to the discovery of a small subset of the Ly6G positive cell cluster that doesn't express Ly6G, but was clustered closely to the CD117 positive Ly6G positive cells, suggesting the similarity of these cells to the neutrophil-lineage based on the expression of the 33 surface markers used in this mass cytometry experiment.A 13 color florescence activated cell sorting panel could then be built, allowing the isolation of the neutrophil progenitors by flow cytometry for downstream functional assays. It is important to perform the bone marrow isolation procedure as quickly as possible and keep the cells at four degrees Celsius during the staining procedure.

preparation-whole-bone-marrow-for-mass-cytometry-analysis-neutrophil

Research

JoVE Journal

Immunology and Infection

9.0K ビュー.  La Jolla Institute for Immunology. この質量サイトメトリープロトコルは、骨髄全体の完全性を維持し、研究対象細胞の分析のための従来のサンプル調製中に失われた情報を救出することを可能にする。この迅速で楽な骨髄分離プロトコルは、まれな好中球系のサブセットのような生存可能な短命骨髄細胞集団の獲得を促進する。質量サイトメトリーを使用して、好中球系細胞などの免疫細胞の下で以前?...