Here, we present a protocol for the in vivo determination of naïve 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 naïve 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 naïve 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.
CD4 T cells and antigen presenting cells (APCs) such as DCs are required mediators of immunity to microbial pathogens1,2. In peripheral lymphoid organs, CD4 T cells are activated upon recognition of specific antigens presented by APCs3,4,5. Activated CD4 T cells proliferate and differentiate into distinct specific effector Th cells that are necessary for the development of a correct adaptive immune response6,7. Control of these processes is critical for producing an adequate adaptive defense that kills the pathogen without producing harmful tissue damage8. Th cells are defined according to the expression or production of surface molecules, transcription factors, and effector cytokines and perform essential and precise functions in response to pathogens1. Cells of the Th1 cell subset express the transcription factor T-bet and the cytokine interferon γ (IFNγ) and participate in host defense against intracellular pathogens1. Quantification of naïve CD4 T cell activation, proliferation, and Th1 differentiation is a useful means of assessing the role T cells play in an immune response.
This protocol enables in vivo analysis of the capacity of in vitro-generated BM-derived DCs to modulate the activation, proliferation, and Th1 differentiation of naïve CD4 T cells. The protocol also serves to assess the capacity of naïve CD4 T cells to be activated, induced to proliferate, and Th1 differentiated (Figure 1). This versatile protocol circumvents the inability to specifically manipulate or select the studied cell population in purely in vivo protocols. The effects of diverse molecules and treatments on DCs can be studied by using BM from genetically modified mice5 or by treating or genetically manipulating isolated BM cells9. Similarly, T cell responses can be explored by obtaining T cells for adoptive transfer from different sources or after several manipulations3,8,10.
The main advantages of this protocol are twofold. T cell activation, proliferation, and Th1 differentiation are analyzed with a flow cytometry approach; and this is combined with in vivo studies, thus averting alterations that may occur in vitro and including cell types and other factors only found in intact organs11.
The use of vital dyes is a widely used technique to track cell proliferation while avoiding the use of radioactivity. The measurement of proliferation with these reagents is based on dye dilution after cell division. Moreover, these dyes can be detected at multiple wavelengths and are easily analyzed by flow cytometry in combination with multiple fluorescent antibodies or markers. We highlight the utility of this protocol by showing how T cell activation, proliferation, and Th1 differentiation can be analyzed by flow cytometry.
Experimental procedures were approved by the Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) and the Comunidad Autónoma de Madrid in accordance with Spanish and European guidelines. Mice were bred in specific pathogen free (SPF) conditions and were euthanized by carbon dioxide (CO2) inhalation.
1. Isolation of Mouse Bone Marrow Cells from Tibias and Femurs
NOTE: The C57BL/6 congenic mouse strain carries the differential leukocyte marker Ptprca, generally recognized as CD45.1 or Ly5.1, whereas wild-type C57BL strains carry the Ptprcb allele, known as CD45.2 or Ly5.2. CD45.1 and CD45.2 variants can be distinguished by flow cytometry using antibodies. CD45.1, CD45.2, and CD45.1/CD45.2 mice can be used as cell sources or as recipients for adoptive transfer, permitting tracing of the distinct cell populations by flow cytometry. Preferentially use age-and sex-matched male or female mice below 12 weeks of age.
2. DC Differentiation, Maturation and Antigen Loading
3. Isolation of Naïve CD4 T Cells from OTII Mice
NOTE: This method yields approximately 100 x 106 spleenocytes per uninfected 8 to 12 week-old C57BL/6 mouse. Both males and females can be used. CD4 T cells can be isolated from spleen or lymph nodes; CD4 T cells account for approximately 25% and 50% of cells in these organs, respectively. Perform the following steps in sterile conditions.
4. In Vivo Activation, Proliferation and Th1 Differentiation Assay
NOTE: The vital cell tracer dye carboxyfluorescein diacetate succinimidyl ester (CFSE) and other succinimidyl ester-based dyes, which are excited and emit fluorescence at different wavelengths, are widely used to assess lymphocyte proliferation by flow cytometry due to their high fluorescence intensity, long-life, low variability, and low toxicity14.
Figure 1 illustrates the steps described in this protocol. Figure 2 illustrates the isolation and culture of mouse BM cells. The addition of GM-CSF and LPS to these cultures allows the in vitro generation and maturation of DCs. Figure 3 illustrates the flow cytometry analysis of the differentiation and maturation of the obtained DCs. OVAp-loaded GM-CSF BM-derived DCs and isolated vital cell trace dye-stained CD4/OTII T cells are adoptively transferred to mice. Figure 4 shows the location of the lymph nodes used for the isolation of CD4/OTII T cells. Figure 5 shows a 50 mL tube fitted with the 70 µm nylon filter and a syringe plunger used to homogenize the lymph nodes and spleen. Figure 6 shows i.v. injection of the CD4/OTII T cells into the retro-orbital plexus and the s.c. injection of the OVAp-loaded GM-CSF BM-derived DCs into the footpad. CD4/OTII T cells distribute to the different lymphoid organs, whereas GM-CSF DCs migrate to the popliteal lymph nodes where GM-CSF DCs activate naïve CD4/OTII T cells by the presentation of OVAp. Naïve CD4/OTII T cells then proliferate and differentiate towards the Th1 phenotype. Figure 7 illustrates the quantification of naïve CD4/OTII T cell activation from the analysis of membrane CD69 and CD25 expression. Figure 8 shows the quantification of CD4/OTII T cell proliferation. Figure 9 illustrates the quantification of CD4/OTII T cell differentiation towards the Th1 phenotype.
Figure 1: Protocol scheme. 1) Isolate BM cells from mouse femurs and tibias. 2) Culture BM cells with GM-CSF to generate GM-CSF BM derived-DCs. 3) Check DC differentiation and mature GM-CSF BM derived-DCs with LPS. 4) Check DC maturation. 5) Load DCs with OVAp. 6) Isolate CD4/OTII T cells form mouse spleen. 7) Stain CD4/OTII T cells with vital cell tracer dye. 8) Check isolation purity and vital cell tracer dye staining of isolated CD4/OTII T cells. 9) Adoptively transfer isolated CD4/OTII T cells i.v. to recipient mice. 10). Adoptively transfer OVAp-loaded and matured DCs s.c. to recipient mice. 11) Check CD4/OTII T cell activation. 12) Check CD4/OTII T cell proliferation and differentiation. Please click here to view a larger version of this figure.
Figure 2: Bone marrow isolation process from mouse femurs and tibias. (A) Skin incision with scissors. (B) Removal of skin from the limb. (C) Muscle incision with scissors. (D) Removal of muscle from the limb with a scalpel. Please click here to view a larger version of this figure.
Figure 3: Flow cytometry analysis of the maturation of GM-CSF BM-derived DCs. Surface expression of MHCII, CD80, and CD86 in LPS activated (+LPS) and non-activated (-LPS) GM-CSF BM-derived DCs. Numbers show the mean fluorescence intensity in arbitrary units (a.u.). Please click here to view a larger version of this figure.
Figure 4: Location of the inguinal, axillary, brachial, cervical, and mesenteric lymph nodes and the spleen in mice. Please click here to view a larger version of this figure.
Figure 5: Experimental set up for lymph node and spleen homogenization. Please click here to view a larger version of this figure.
Figure 6: Adoptive transfer of CD4/OTII T cells and OVAp-loaded GM-CSF BM-derived-DCs. (A) Intravenous injection of CD4/OTII T cells into the retro-orbital plexus. (B) Subcutaneous injection of OVAp-loaded GM-CSF BM-derived DCs into the footpad. Please click here to view a larger version of this figure.
Figure 7: Quantification of T cell activation in vivo. Flow cytometry plots and graph showing the analysis and quantification of the membrane expression of CD69 in CD4 T cells. CD45.1/CD45.2 mice were adoptively transferred i.v. with mouse CD45.1/CD4/OTII and CD45.1/CD4/OTII cells 24 h before the s.c. adoptive transfer of OVAp-loaded GM-CSF BM-derived-DCs. T cell activation was measured at 2 days post-DC transfer by flow cytometry after staining with fluorescent-tagged antibodies to the indicated antigens. Please click here to view a larger version of this figure.
Figure 8: Quantification of T cell proliferation in vivo. Flow cytometry plots and graphs showing the analysis and quantification of the decline vital cell tracer dye staining in proliferating CD4 T cells. CD45.2 mice were adoptively transferred i.v. with mouse CD45.1/CD4/OTII cells 24 h before the s.c. adoptive transfer of OVAp-loaded GM-CSF BM-derived-DCs. T cell proliferation was measured at 5 days post-DC transfer by flow cytometry after staining with the indicated fluorescent antibodies. T cell proliferation can be determined by measuring the percentage of proliferating cells, the percentage of cells in each division peak, or by counting the number of division peaks as shown in the graphs. Please click here to view a larger version of this figure.
Figure 9: Quantification of T cell differentiation towards Th1 phenotype in vivo. Flow cytometry plots and graphs showing the analysis and quantification of the percentage of IFNγ-expressing CD4 T cells. CD45.2 mice were adoptively transferred i.v. with mouse CD45.1/CD4/OTII cells 24 h before the s.c. adoptive transfer of OVAp-loaded GM-CSF BM-derived-DCs. T cell differentiation was measured at days post-DC transfer by flow cytometry after staining with the indicated fluorescent antibodies. T cell differentiation towards the Th1 phenotype was determined as IFNγ-expressing cells as a percentage of total CD4 T cells and from only the proliferating CD4 T cells. Please click here to view a larger version of this figure.
This protocol allows for the characterization of the capacity of BM-derived DCs to modulate the activation, proliferation, and differentiation of naïve CD4 T cells. Moreover, it can also be used to assess the susceptibility of CD4 T cells to modulation by BM-derived DCs. With this protocol, changes in these events can be measured in vivo.
Depending on the hypothesis under investigation, several combinations of T cells and DCs can be used. For example, one can analyze the consequences of knocking in or knocking out specific genes or the efficiency of a specific stimulus of CD4 T cell activation, proliferation, or Th1 differentiation. These procedures can be performed on DCs or CD4 T cells or on both cell types. Thus, CD4 T cells from wild-type or genetically modified mice can be combined with DCs derived from wild-type mice and vice versa.
This protocol can be adapted to distinguish the origin of the different cell populations by using flow cytometry and antibodies against CD45.1 and CD45.2. Indeed, CD45.1/CD45.1 and CD45.2/CD45.2 mice can be used as the source of any of the cell types used or as recipients for adoptive transfer in any combination. For example, CD4 T cells can be obtained from CD45.1/CD45.1/OTII mice while CD45.2/CD45.2 mice can be the origin of BM for DC generation. In this experiment, both cell types can be adoptively transferred to CD45.1/CD45.2 mice. Furthermore, CD4/OTII T cells from CD45.1/CD45.1 type one mice and CD45.2/CD45.2 type two mice can be combined in the same or different CD45.1/CD45.2 type three recipients to compare the behavior of type one and type two CD4 T cell populations in competing and non-competing conditions, respectively.
This method describes the generation of GM-CSF BM-derived DCs. However, alternative protocols are available for DC maturation and differentiation; for example, papain can be used instead of LPS or fms-related tyrosine kinase 3 ligand (Flt3-L) instead of GM-CSF, allowing study of the capacity of phenotypically distinct DCs to activate CD4 T cell adaptive immunity. With the same intention, DCs for antigen loading and presentation can be directly isolated from mice. Combination of this protocol with others9 allows the manipulation of naïve CD4/OTII T cells by viral infection16 before their adoptive transfer to recipient mice. BM can be also transduced with retroviruses9 to study the effect of controlled cell modifications on DCs before their use in the protocol.
Additionally, this protocol can be adapted for intravital microscopy studies17 by using fluorescent protein-expressing cells. For example, CD4/OTII mice can be crossed with GFP- or cherry-expressing mice to obtain GFP or Cherry/OTII CD4 mice. These mice can then be used as a source of CD4 T cells and can be combined with BM-derived DCs from cherry- or GFP-expressing mice, as required, in vivo experiments.
The authors have nothing to disclose.
We thank Dr. Simon Bartlett for English editing. This study was supported by grants from Instituto de Salud Carlos III (ISCIII) (PI14/00526; PI17/01395; CP11/00145; CPII16/00022), the Miguel Servet Program and Fundación Ramón Areces; with co-funding from the Fondo Europeo de Desarrollo Regional (FEDER). The CNIC is supported by the Ministry of Economy, Industry and Competitiveness (MEIC), and the Pro CNIC Foundation and is a Severo Ochoa Center of Excellence (SEV-2015-0505). RTF is founded by Fundación Ramón Areces and CNIC, VZG by ISCIII, BHF by Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12) and JMG-G by the ISCIII Miguel Servet Program and imas12.
Ethanol | VWR Chemicals | 20,824,365 | 5 L |
Scissors | Fine Science Tools (F.S.T.) | 14001-12 | |
Forceps | Fine Science Tools (F.S.T.) | 11000-13 | |
Fine Forceps | Fine Science Tools (F.S.T.) | 11253-20 | |
Scalpel | Fine Science Tools (F.S.T.) | 10020-00 | Box of 100 blades |
Fetal Bovine Serum | SIGMA | F7524 | |
Penicillin/streptomycin | LONZA | DE17-602E | |
Roswell Park Memorial Institute medium (RPMI) | GIBCO | 21875-034 | |
Sterile Petri dishes | Falcon | 353003 | |
25-gauge needle | BD Microlance 3 | 300600 | |
1 ml syringe | Novico | N15663 | |
15 ml conical tubes | Falcon | 352096 | |
50 ml conical tubes | Falcon | 352098 | |
70 μm nylon web filter | BD Falcon | 352350 | |
Red blood lysis buffer | SIGMA | R7757 | 100 Ml |
EDTA | SIGMA | ED2SS-250 | |
Bovine Serum Albumin | SIGMA | A7906 | 100 g |
Trypan blue | SIGMA | 302643-25G | |
Culture-plates | Falcon | 353003 | |
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) | Cambrex | BE17-737E | |
Beta-mercaptoethanol | Merck | 8-05740-0250 | |
Sodium pyruvate | LONZA | BE13-115E | |
L-glutamine | LONZA | BE17-605E | |
Recombinant murine Granulocyte Macrophage colony-stimulating factor (GM-CSF) | Prepotech | 315-03 | |
lipopolysaccharide (LPS) | SIGMA-ALDRICH | L2018 | |
96-well-plate | Costar | 3799 | |
v450 anti-mouse CD11b antibody | BD Biosciences | 560455 | |
PE anti-mouse CD64 antibody | BioLegend | 139303 | |
PE anti-mouse CD115 antibody | BioLegend | 135505 | |
FITC anti-mouse CD11c antibody | BioLegend | 117305 | |
FITC anti-mouse MHCII antibody | BioLegend | 125507 | |
APC anti-mouse CD86 antibody | BioLegend | 105011 | |
APC anti-mouse CD80 antibody | BioLegend | 104713 | |
Flow Cytometry tubes | Zelian | 300800-1 | PS 12X75 5mL |
OTII Ovoalbumine peptide | InvivoGen | 323-339 | |
anti-mouse biotinylated CD8α antibody | Tonbo Biosciences | 30-0081-U500 | |
anti-mouse biotinylated IgM antibody | BioLegend | 406503 | |
anti-mouse biotinylated B220 antibody | Tonbo Biosciences | 30-0452-U500 | |
anti-mouse biotinylated CD19 antibody | Tonbo Biosciences | 30-0193-U500 | |
anti-mouse biotinylated MHCII (I-Ab) antibody | BioLegend | 115302 | |
anti-mouse biotinylated CD11b antibody | Tonbo Biosciences | 30-0112-U500 | |
anti-mouse biotinylated CD11c antibody | BioLegend | 117303 | |
anti-mouse biotinylated CD44 antibody | BioLegend | 103003 | |
anti-mouse biotinylated CD25 antibody | Tonbo Biosciences | 30-0251-U100 | |
anti-mouse biotinylated DX5 antibody | BioLegend | 108903 | |
streptavidin-coated magnetic microbeads | MACS Miltenyi Biotec | 130-048-101 | |
Magnetic cell separator | MACS Miltenyi Biotec | 130-090-976 | QuadroMACS Separator |
Separation columns | MACS Miltenyi Biotec | 130-042-401 | |
PE anti-mouse CD4 antibody | BioLegend | 100408 | |
APC anti-mouse CD3 antibody | BioLegend | 100235 | |
FITC anti-mouse CD8 antibody | Tonbo Biosciences | 35-0081-U025 | |
Cell Violet Tracer | Thermofisher | C34557 | |
APC anti-mouse CD25 antibody | Tonbo Biosciences | 20-0251-U100 | |
Alexa647 anti-mouse CD69 antibody | BioLegend | 104518 | |
PerCPCY5.5 anti-mouse CD45.1 antibody | Tonbo Biosciences | 65-0453 | |
APC anti-mouse CD45.1 antibody | Tonbo Biosciences | 20-0453 | |
PECY7 anti-mouse CD45.1 antibody | Tonbo Biosciences | 60-0453 | |
FITC anti-mouse CD45.2 antibody | Tonbo Biosciences | 35-0454 | |
Ionomycin | SIGMA-ALDRICH | I0634 | |
Phorbol 12 Myristate 13 Acetate (PMA) | SIGMA | P8139 | |
Brefeldin A (BD GolgiPlug) | BD | 555029 | |
Paraformaldehyde | Millipore | 8-18715-02100 | |
Intracellular permeabilization buffer | eBioscience | 00-8333 | |
APC anti-mouse IFNg antibody | Tonbo Biosciences | 20-7311-U100 | |
Fc-block (anti-mouse CD16/CD32) | Tonbo Biosciences | 70-0161-U100 | |
B6.SJL CD45.1 mice | The Jackson Laboratory | 002014 | |
BD LSRFortessa™ Cell Analyzer | BD Biosciences | 649225 | |
DAPI Solution | Thermofisher | 62248 |