This work was supported by Program of Tianjin Science and Technology Plan (20JCQNJC00550), Tianjin Health Science and Technology Project (TJWJ202021QN033 and TJWJ202021QN034).

All procedures were approved by the Nanjing Medical University Animal Care and Use Committee.
1. Isolation of bone marrow and preparation of BM cells
<ol>
	<li>Sacrifice C57BL/6 mice (18-22 g, 6-8 weeks old) via CO2 asphyxiation. Fix the mouse on the mouse operating table. Disinfect the surfaces with 70% ethanol.</li>
	<li>Cut the skin of the leg to expose the muscles and femoral artery. Clamp and tear off the femoral artery using two forceps, then pull the proximal end toward the abdomen. 
	NOTE: Do not cut the femoral artery directly. Otherwise, it will cause excessive bleeding and contaminate the field of vision.</li>
	<li>Cut all the muscles around the femur.</li>
	<li>Slowly stretch the lower limbs of the mouse outward until the sound of hip joint dislocation is heard and the femoral head prolapse is visible.</li>
	<li>Separate the lower limbs from the body using scissors along the inside of the femoral head.</li>
	<li>Cut the hind legs from the end of the knee joint to obtain a free and complete femur.</li>
	<li>Remove the muscles attached to the femur using gauze. 
	NOTE: Do not tear the muscles directly. The femur of mice is delicate, its integrity must be maintained.</li>
	<li>Immerse the femur in 75% alcohol for 2-5 min.</li>
</ol>
2. Induction culture of BMDC
<ol>
	<li>Rinse the residual alcohol with PBS. Use hemostatic forceps to clamp the middle and bottom part of the femur and another set to clamp the lower end of the femur. The hemostatic forceps are applied laterally to the femur, and the femur is separated from the epiphyseal line. 
	NOTE: The epiphyseal line is not easily visible until the femur fractures. This and the next steps are all performed in a sterile environment.</li>
	<li>Use a 1 mL syringe (needle: 0.6 mm x 25 mm) to penetrate the bone marrow cavity from the epiphyseal line break and rotate the needle to penetrate the femoral head and through the bone marrow cavity. Pulse and flush the bone marrow cavity using 1 mL of the complete medium containing GM-CSF/IL-4 until the bone becomes white. 
	NOTE: Complete culture medium: 10% FBS, 1% penicillin-streptomycin, 55 &#181;M &#946;-Mercaptoethanol, 10 ng/mL GM-CSF, and 10 ng/mL IL-4.</li>
	<li>Resuspend all the cells in 24 mL of complete culture medium (~5 x 105 cells/mL). After mixing, all the medium was seeded on a 6-well plate with 4 mL/well, then incubated at 37 &#176;C with 5% CO2 for 2 days. 
	NOTE: It is not necessary to lyse erythrocytes.</li>
	<li>Replace all the medium after 2 days with medium containing GM-CSF/IL-47. On the fourth, sixth, and eighth days, replace half of the medium with the complete medium containing 10 ng/mL GM-CSF/IL-4. 
	NOTE: In this step, suspended cells such as erythrocytes and lymphocytes are removed.</li>
	<li>Take pictures every day to record cell growth. Starting from day six, harvest one well of cells per day to count the cell number and detect CD11c, CD80, and MHC II expression6,7.</li>
</ol>
3. Flow cytometric detection of the expression of CD11c, CD80, and MHC II
<ol>
	<li>After washing the DCs with PBS, resuspend 1 x 106 cells in 100 &#181;L of FACS buffer, add 0.5 &#181;g of anti-mouse CD16/32 antibody, and incubate for 10 min on ice to block non-specific antigen sites.</li>
	<li>Add 1 &#181;g of Percp/cy5.5-CD11c, 0.5 &#181;g of PE-CD80, and 0.04 &#181;g of APC-MHC II antibodies, and incubate on ice for 30 min.</li>
	<li>Centrifuge at 1,000 x g for 3 min at 4 &#176;C, remove the supernatant, add 1 mL of 4% paraformaldehyde, fix for 30 min at 4 &#176;C, and re-suspend in 300 &#181;L of FACS buffer.</li>
	<li>Perform flow cytometry.</li>
</ol>

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All authors declare they have no conflicts of interest and that they have nothing to disclose.

Humans and mice have different DC subsets, including classical DCs (cDCs, including cDC1s and cDC2s) plasmacytoid DCs (pDCs), and monocyte-derived DCs (MoDCs)9,10,11. It is generally accepted that cDC1s regulate cytotoxic T lymphocyte (CTL) responses to intracellular pathogens and cancer, and cDC2s regulate immune responses to extracellular pathogens, parasites, and allergens12. A significant number of DC...

Dendritic cells (DCs) are the most powerful antigen-presenting cells (APCs) for activating na&#239;ve T cells and inducing specific cytotoxic T lymphocyte (CTL) responses against infectious diseases, allergy diseases, and tumor cells1,2,3. DCs are the primary link between innate immunity and adaptive immunity and play an essential role in immunological defense and the maintenance of immune tolerance. In the last 40 years, many researchers have sought to define the subsets of DCs and their functions in inflammation and immunity. As per those studies, DCs develop along the myeloid and lymphoid lineages from bone marrow cells. Tumor vaccines have gained significant milestones in recent years and have a promising future. Mechanically, tumor vaccines modulate the immune response and prevent tumor growth by activating cytotoxic T lymphocytes using tumor antigens. The vaccine based on DCs plays an important role in tumor immunotherapy and has been identified as one of the most promising anti-tumor therapies1,4. In addition, DCs have been widely used in the testing of new molecular-targeted drugs and immune checkpoint inhibitors5.
Researchers urgently need a high number of high-purity DCs to further study the role of DCs. However, DCs are rare in various tissues and blood, accounting for only 1% of blood cells in humans and animals. In vitro culture of bone marrow dendritic cells (BMDC) is an important method for obtaining large amounts of DC cells. Meanwhile, The Lutz protocol for generating DCs from bone marrow has been widely used by researchers6. Although the protocol is effective in obtaining DC cells, it is complex and expensive, involving the addition of high concentrations of cytokines and the lysis of red blood cells.
In this study, we report a method for isolating almost all bone marrow cells from mouse bone marrow (BM) and inducing differentiation into BMDC after 7-9 days of incubation in vitro, with a lower concentration of GM-CSF and IL-4. This procedure only takes 10 min to harvest almost all bone marrow cells and to suspend them in a complete medium. In brief, we provide an efficient and cost-effective culturing method for BMDC in this research.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>&#946;-Mercaptoethanol</td>
			<td>Solarbio</td>
			<td>M8211</td>
			<td></td>
		</tr>
		<tr>
			<td>6-well plate</td>
			<td>Corning</td>
			<td>3516</td>
			<td></td>
		</tr>
		<tr>
			<td>APC-MHC II</td>
			<td>Biolegend</td>
			<td>116417</td>
			<td></td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>Gibco</td>
			<td>10100</td>
			<td></td>
		</tr>
		<tr>
			<td>PE-CD80</td>
			<td>Biolegend</td>
			<td>104707</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin</td>
			<td>Solarbio</td>
			<td>P1400</td>
			<td></td>
		</tr>
		<tr>
			<td>Percp/cy5.5-CD11c</td>
			<td>Biolegend</td>
			<td>117327</td>
			<td></td>
		</tr>
		<tr>
			<td>PRMI-1640</td>
			<td>Thermo</td>
			<td>11875093</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant Mouse GM-CSF</td>
			<td>Solarbio</td>
			<td>P00184</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant Mouse IL-4</td>
			<td>Solarbio</td>
			<td>P00196</td>
			<td></td>
		</tr>
		<tr>
			<td>TruStain Fc PLUS (anti-mouse CD16/32) Antibody</td>
			<td>Biolegend</td>
			<td>156603</td>
			<td></td>
		</tr>
	</tbody>
</table>

economical and efficient protocol for isolating and culturing bone marrow-derived dendritic cells from mice

The demand for dendritic cells (DCs) is gradually increasing as immunology research advances. However, DCs are rare in all tissues. The traditional method for isolating DCs primarily involves inducing bone marrow (BM) differentiation into DCs by injecting large doses (&#62;10 ng/mL) of granulocyte-macrophage colony-stimulating factor/interleukin-4 (GM-CSF/IL-4), making the procedure complex and expensive. In this protocol, using all BM cells cultured in 10 ng/mL GM-CSF/IL-4 medium, after 3-4 half-culture exchanges, up to 2.7 x 107 CD11c+ cells&#160;(DCs) per mouse (two femurs) were harvested with a purity of 80%-95%. After 10 days in culture, the expression of CD11c, CD80, and MHC II increased, whereas the number of cells decreased. The number of cells peaked after 7 days of culture. Moreover, this method only took 10 min to harvest all bone marrow cells, and a high number of DCs were obtained after 1 week of culture.

The 1 x 107-1.7 x 107 cells were extracted from two femurs and were re-suspended in 24 mL of medium before being planted in a 6-well plate (Figure 1A). After 2 days, non-adherent cells were removed by completely changing the culture medium. Before changing the medium, a significant number of suspended cells were observed (Figure 1B). After 3 days of culture, small cell colonies began to form. On the sixth day, the size and number of colonie...

Watch this Scientific Journal Video about Economical and Efficient Protocol for Isolating and Culturing Bone Marrow-derived Dendritic Cells from Mice at JoVE.com

Economical and Efficient Protocol for Isolating and Culturing Bone Marrow-derived Dendritic Cells from Mice

Here, we present an economical and efficient method to isolate and generate high-purity bone marrow-derived dendritic cells from mice after 7 days of culture with 10 ng/mL GM-CSF/IL-4.

The demand for dendritic cells (DCs) is gradually increasing as immunology research advances. However, DCs are rare in all tissues. The traditional method ...

economical-efficient-protocol-for-isolating-culturing-bone-marrow

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Immunology and Infection

8.2K Views.  The Second Hospital of Tianjin Medical University. Here, we present an economical and efficient method to isolate and generate high-purity bone marrow-derived dendritic cells from mice after 7 days of culture with 10 ng/mL GM-CSF/IL-4.

Video: Economical and Efficient Protocol for Isolating and Culturing Bone Marrow-derived Dendritic Cells from Mice

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

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

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

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

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

Investigation of Macrophage Polarization Using Bone Marrow Derived Macrophages

The article describes a readily easy adaptive in vitro model to investigate macrophage polarization. In the presence of GM-CSF/M-CSF, hematopoietic stem/progenitor cells from the bone marrow are directed into monocytic differentiation, followed by M1 or M2 stimulation. The activation status can be tracked by changes in cell surface antigens, gene expression and cell signaling pathways.

The article describes a readily easy adaptive in vitro model to investigate macrophage polarization. In the presence of GM-CSF/M-CSF, hematopoietic stem/progenitor cells from the bone marrow are directed into monocytic differentiation, followed by M1 or M2 stimulation. The activation status can be tracked by changes in cell surface antigens, gene expression and cell signaling pathways.

The article describes a readily easy adaptive in vitro model to investigate macrophage polarization. In the presence of GM-CSF/M-CSF, hematopoietic ...

Isolation of Myeloid Dendritic Cells and Epithelial Cells from Human Thymus

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

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

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

Bone Marrow-derived Macrophage Production

Macrophages are critical components of the innate and adaptive immune responses, and they are the first line of defense against foreign invaders because of their powerful microbicidal activities. Macrophages are widely distributed throughout the body and are present in the lymphoid organs, liver, lungs, gastrointestinal tract, central nervous system, bone, and skin. Because of their repartition, they participate in a wide range of physiological and pathological processes. Macrophages are highly versatile cells that are able to recognize microenvironmental alterations and to maintain tissue homeostasis. Numerous pathogens have evolved mechanisms to use macrophages as Trojan horses to survive, replicate in, and infect both humans and animals and to propagate throughout the body. The recent explosion of interest in evolutionary, genetic, and biochemical aspects of host-pathogen interactions has renewed scientific attention regarding macrophages. Here, we describe a procedure to isolate and cultivate macrophages from murine bone marrow that will provide large numbers of macrophages for studying host-pathogen interactions as well as other processes.

Macrophages have long been recognized as a critical component of the innate and adaptive immune responses. The recent explosion of knowledge pertaining to evolutionary, genetic, and biochemical aspects of the interaction between macrophages and microbes has renewed scientific attention to macrophages. This article describes a method to differentiate macrophages from mouse bone marrow.

Macrophages are critical components of the innate and adaptive immune responses, and they are the first line of defense against foreign invaders because ...

Isolation and Intravenous Injection of Murine Bone Marrow Derived Monocytes

As a subtype of leukocytes and progenitors of macrophages, monocytes are involved in many important processes of organisms and are often the subject of various fields in biomedical science. The method described below is a simple and effective way to isolate murine monocytes from heterogeneous bone marrow.
Bone marrow from the femur and tibia of Balb/c mice is harvested by flushing with phosphate buffered saline (PBS). Cell suspension is supplemented with macrophage-colony stimulating factor (M-CSF) and cultured on ultra-low attachment surfaces to avoid adhesion-triggered differentiation of monocytes. The properties and differentiation of monocytes are characterized at various intervals. Fluorescence activated cell sorting (FACS), with markers like CD11b, CD115, and F4/80, is used for phenotyping. At the end of cultivation, the suspension consists of 45%&#177; 12% monocytes. By removing adhesive macrophages, the purity can be raised up to 86%&#177; 6%. After the isolation, monocytes can be utilized in various ways, and one of the most effective and common methods for in vivo delivery is intravenous tail vein injection. 
This technique of isolation and application is important for mouse model studies, especially in the fields of inflammation or immunology. Monocytes can also be used therapeutically in mouse disease models.

Here we present a protocol that generates large amounts of murine monocytes from heterogeneous bone marrow for translational applications. In comparison to others, this new method helps reduce the number of sacrificed animals and lowers costs by avoiding expensive methods such as high gradient magnetic cell separation (MACS).

As a subtype of leukocytes and progenitors of macrophages, monocytes are involved in many important processes of organisms and are often the subject of ...

T Cells Capture Bacteria by Transinfection from Dendritic Cells

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

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

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

Efficient Isolation Protocol for B and T Lymphocytes from Human Palatine Tonsils

Tonsils form a part of the immune system providing the first line of defense against inhaled pathogens. Usually the term &#8220;tonsils&#8221; refers to the palatine tonsils situated at the lateral walls of the oral part of the pharynx. Surgically removed palatine tonsils provide a convenient accessible source of B and T lymphocytes to study the interplay between foreign pathogens and the host immune system. This video protocol describes the dissection and processing of surgically removed human palatine tonsils, followed by the isolation of the individual B and T cell populations from the same tissue sample. We present a method, which efficiently separates tonsillar B and T lymphocytes using an antibody-dependent affinity protocol. Further, we use the method to demonstrate that human adenovirus infects specifically the tonsillar T cell fraction. The established protocol is generally applicable to efficiently and rapidly isolate tonsillar B and T cell populations to study the role of different types of pathogens in tonsillar immune responses.

Palatine tonsils are a rich source of B and T lymphocytes. Here we provide an easy, efficient and rapid protocol to isolate B and T lymphocytes from human palatine tonsils. The method described has been specifically adapted for studies of the viral etiology of tonsil inflammation known as tonsillitis.

Tonsils form a part of the immune system providing the first line of defense against inhaled pathogens. Usually the term &#8220;tonsils&#8221; refers to ...

Generation and Identification of GM-CSF Derived Alveolar-like Macrophages and Dendritic Cells From Mouse Bone Marrow

Macrophages and dendritic cells (DCs) are innate immune cells found in tissues and lymphoid organs that play a key role in the defense against pathogens. However, they are difficult to isolate in sufficient numbers to study them in detail, therefore, in vitro models have been developed. In vitro cultures of bone marrow-derived macrophages and dendritic cells are well-established and valuable methods for immunological studies. Here, a method for culturing and identifying both DCs and macrophages from a single culture of primary mouse bone marrow cells using the cytokine granulocyte macrophage colony-stimulating factor (GM-CSF) is described. This protocol is based on the established procedure first developed by Lutz et al. in 1999 for bone marrow-derived DCs. The culture is heterogeneous, and MHCII and fluoresceinated hyaluronan (FL-HA) are used to distinguish macrophages from immature and mature DCs. These GM-CSF derived macrophages provide a convenient source of in vitro derived macrophages that closely resemble alveolar macrophages in both phenotype and function.

Bone marrow cells cultured with granulocyte macrophage colony stimulating factor (GM-CSF) generate a heterogeneous culture containing macrophages and dendritic cells (DCs). This method highlights using MHCII and hyaluronan (HA) binding to differentiate macrophages from the DCs in the GM-CSF culture. Macrophages in this culture have many similarities to alveolar macrophages.

Macrophages and dendritic cells (DCs) are innate immune cells found in tissues and lymphoid organs that play a key role in the defense against pathogens. ...

Fluorescence-activated Cell Sorting for Purification of Plasmacytoid Dendritic Cells from the Mouse Bone Marrow

Fluorescence-activated cell sorting (FACS) is a technique to purify specific cell populations based on phenotypes detected by flow cytometry. This method enables researchers to better understand the characteristics of a single cell population without the influence of other cells. Compared to other methods of cell enrichment, such as magnetic-activated cell sorting (MCS), FACS is more flexible and accurate for cell separation due to the ability of phenotype detection by flow cytometry. In addition, FACS is usually capable of separating multiple cell populations simultaneously, which improves the efficiency and diversity of experiments. Although FACS has some limitations, it has been broadly used to purify cells for functional studies in both in vitro and in vivo settings. Here we report a protocol using fluorescence-activated cell sorting to isolate a very rare population of immune cells, plasmacytoid dendritic cells (pDC), with high purity from the bone marrow of lupus-prone mice for in vitro functional studies of pDC.

We report a protocol using fluorescence-activated cell sorting to isolate plasmacytoid dendritic cells (pDC) with high purity from the bone marrow of lupus-prone mice for functional studies of pDC.

Fluorescence-activated cell sorting (FACS) is a technique to purify specific cell populations based on phenotypes detected by flow cytometry. This method ...

An In Vivo Mouse Model to Measure Na&#239;ve CD4 T Cell Activation, Proliferation and Th1 Differentiation Induced by Bone Marrow-derived Dendritic Cells

Quantification of na&#239;ve CD4 T cell activation, proliferation, and differentiation to T helper 1 (Th1) cells is a useful way to assess the role played by T cells in an immune response. This protocol describes the in vitro differentiation of bone marrow (BM) progenitors to obtain granulocyte macrophage colony-stimulating factor (GM-CSF) derived-dendritic cells (DCs). The protocol also describes the adoptive transfer of ovalbumin peptide (OVAp)-loaded GM-CSF-derived DCs and na&#239;ve CD4 T cells from OTII transgenic mice in order to analyze the in vivo activation, proliferation, and Th1 differentiation of the transferred CD4 T cells. This protocol circumvents the limitation of purely in vivo methods imposed by the inability to specifically manipulate or select the studied cell population. Moreover, this protocol allows studies in an in vivo environment, thus avoiding alterations to functional factors that may occur in vitro and including the influence of cell types and other factors only found in intact organs. The protocol is a useful tool for generating changes in DCs and T cells that modify adaptive immune responses, potentially providing important results to understand the origin or development of numerous immune associated diseases.

An &lt;em&gt;In Vivo&lt;/em&gt; Mouse Model to Measure Na&amp;#239;ve CD4 T Cell Activation, Proliferation and Th1 Differentiation Induced by Bone Marrow-derived Dendritic Cells

Here, we present a protocol for the in vivo determination of na&#239;ve CD4 T cell (T cell) activation, proliferation, and Th1 differentiation induced by GM-CSF bone marrow (BM)-derived dendritic cells (DCs). In addition, this protocol describes BM and T-cell isolation, DC generation, and DC and T-cell adoptive transfer.

Quantification of na&#239;ve CD4 T cell activation, proliferation, and differentiation to T helper 1 (Th1) cells is a useful way to assess the role played ...