The authors acknowledge the Special Topic of Laboratory Management of Jiangnan University: Construction of Digital Slice Library Based on Pathological Specimens (JDSYS202223) and the National Natural Science Foundation of China (81800065).

All experiments were performed in accordance with the Guide for the Care and Use of Laboratory Animals. All the animal experiments were approved by the Experimental Animal Welfare Ethics committee of Jiangnan University (JN No. 20211130m1720615[501]).
NOTE: In total, 10 male C57BL/6 mice aged 6-8 weeks old and weighing 20-25 g were used in this study. The three experimental groups in the study included three recipient mice each, and one host mouse was used for the IM isolation.
1. Depletion of mouse pulmonary macrophages
<ol>
	<li>Take out the vial of clodronate liposomes (see Table of Materials) from the refrigerator 30 min in advance, warm it to room temperature, and invert it several times to ensure uniform mixing. 
	NOTE: Clodronate liposomes encapsulate the hydrophilic dichloromethylene bisphosphonate molecules. When these liposomes are consumed by the macrophages, the clodronate is gradually released by the action of the lysosome phosphatase, and its accumulation consequently triggers cell apoptosis and the depletion of macrophages7.</li>
	<li>Anesthetize mice with 3% isoflurane. Check the depth of anesthesia by pinching one foot to check consciousness. Apply veterinary ointment to both eyes to prevent dryness under anesthesia.</li>
	<li>Aspirate 60 &#181;L of clodronate liposomes using a pipette with a sterile suction tip. Administer the drug dropwise into the nasal cavity of the anesthetized mouse, such that when the mouse inhales, the drug is inhaled into the trachea. After each drop, make sure the mouse inhales the drug completely and is breathing evenly. Administer liposomes containing PBS alone as a control8 (Figure 2).</li>
	<li>Place the mice on a 38 &#176;C constant temperature table for rewarming to speed up their recovery. Monitor the mice until they wake up. After the mice recover well and achieve sternal recumbency, transfer them to the cage.</li>
	<li>Use mice with depleted alveolar macrophages 2 days after the treatment with clodronate liposomes as the recipient mice for the transfer experiment. 
	&#8203;NOTE: In this study, the depletion of alveolar macrophages was confirmed by checking the expression of macrophage markers as described earlier8,9 following the administration of clodronate liposomes by inhalation (see Supplementary Figure 1).</li>
</ol>
2. Isolation and culture of IMs
<ol>
	<li>Anesthetize the host mouse&#160;with an intraperitoneal injection of Ketamine (120 mg/kg) and Xylazine (16 mg/kg). Confirm the depth of anesthesia via loss of the toe pinch reflex. Apply veterinary ointment to both eyes to prevent dryness under anesthesia. Then, disinfect the skin of the anesthetized mouse with 75% alcohol and iodine. Use scissors to cut through the skin and expose the cardiopulmonary tissue</li>
	<li>Aspirate 10 mL of 1x PBS in a syringe with a 20 G needle and insert the tip of the needle into the right atrium of the mouse (Figure 3A). Cut the inferior vena cava of the mouse with surgical scissors, and then manually perfuse the mouse with PBS at a constant speed (10-20 mL/min) until the lung tissue turns white. Excise the lung tissue and transfer it into ice-cold PBS in a culture dish (Figure 3B).</li>
	<li>Cut the lung tissue into fragments of approximately 2 mm x 2 mm x 2 mm. Then, add 15 mL of Dulbecco&#39;s modified Eagle&#39;s medium (DMEM) containing 1% collagenase A to the lung tissue to isolate the macrophages. Incubate at 100 rpm for 30 min on a 37 &#176;C shaking table.</li>
	<li>Aspirate the lung tissue suspension through a 10 mL syringe at least 20x to make it as fine as possible. Filter this suspension through a 40 &#181;m cell strainer. Centrifuge the filtrate at 400 x g for 10 min and discard the supernatant.</li>
	<li>Lyse the red blood cells in the pellet by adding 3 mL of RBC lysis buffer (see Table of Materials) on ice for 2-3 min.</li>
	<li>After centrifugation at 150 x g for 5 min, resuspend the cell pellet with 10 mL of DMEM (containing 100 U/mL penicillin and 100 &#181;g/mL streptomycin). Count the cells using a hemocytometer.</li>
	<li>Seed the cells into 10 cm adherent cell culture dishes at 2 x 107 cells/dish, and incubate for 1 h at 37 &#176;C and 5% CO2. This allows the lung IMs to adhere to the dish5. After 1 h, aspirate the supernatant and floating cells, and add 10 mL of fresh complete culture medium (DMEM containing 10% FBS, 100 U/mL penicillin, and 100 &#181;g/mL streptomycin). Incubate for more than 8 h or overnight.</li>
	<li>Determine the purity of the obtained IMs using flow cytometry with staining for F4/80 and CD11c markers, as described earlier5 (see Supplementary Figure 1).</li>
</ol>
3. Adoptive transfer of IMs into the lung alveoli
<ol>
	<li>Replace the culture medium from the plate containing the isolated pulmonary IMs (step 2.7) with a complete culture medium containing 10 ng/mL IL-33 for stimulating the IMs. Incubate for 24 h at 37 &#176;C and 5% CO2. Use 1x PBS in place of IL-33 as a control.</li>
	<li>Dissociate the pulmonary IMs by treating them with 1 mL of 0.25% trypsin for 5 min. Then, quench the digestion by adding 3 mL of fresh culture complete medium, and harvest the pulmonary macrophages by centrifuging the cell suspension at 150 x g and 4 &#176;C for 5 min. Count the cells using a hemocytometer, and resuspend the cells in PBS to a final concentration of 5 x 105 cells/50 &#181;L.</li>
	<li>Anesthetize the recipient mice with 3% isoflurane gas. Wait for the mouse to become unconscious (as in step 1.2), and then fix the limbs of the anesthetized mouse on a vertical plate with medical tape. Gently pull the mouse&#39;s tongue to one side using a cotton swab.</li>
	<li>Turn on the intubation lamp and shine it on the throat of the mouse so that the trachea can be seen. Check that the trachea is close to the base of the tongue, the esophagus is near the back of the neck, but the opening of the esophagus is not visible during the operation.</li>
	<li>Use the intubation lamp (22 G) to help intubate the mouse. Guide the indwelling needle cannula into the trachea with a guide wire (0.4 mm diameter). Remove the guide wire and push the cannula into the mouse trachea to complete the intubation.</li>
	<li>After the cannula is observed to enter the trachea, inject 50 &#181;L of the cell suspension (containing 5 x 105 IMs) into the recipient mouse through the trachea.</li>
	<li>Place the mice on a 38&#176;C constant warming pad for rewarming to speed up the recovery. Monitor the mice until they wake up. After they recover well and achieve sternal recumbency, transfer them to the cage.</li>
	<li>After 24 h, administer bleomycin (BLM) via the trachea (using the procedure in steps 3.3-3.5) at a dose of 1.4 U/kg body weight to induce IPF. Administer an equal volume of saline to the control group.</li>
	<li>After 21 days, determine the degree of severity of pulmonary fibrosis for the different groups of mice that were adoptively transferred with PBS or the IL-33-stimulated IM suspension by evaluating the expression of markers for fibrosis and the Ashcroft scores10.
	<ol>
		<li>Extract the total RNA from the lung tissue using an RNA extraction reagent (see Table of Materials). 
		NOTE: Quantitative analysis was carried out with a microplate reader. If the OD260/OD280 ratio is 1.8-2.0, the RNA purity is high. All the samples were stored at &#8722;80 &#176; C.</li>
		<li>Perform fluorescence quantitative PCR to evaluate the expression of &#945;-smooth muscle actin (SMA) and fibronectin using specific primers. 
		&#8203;NOTE: The primers used for &#945;-SMA were forward 5&#39;- GACGCTGAAGTATCCGATAGAACACG-3&#39; and reverse 5&#39;-CACCATCTCCAGAGTCCAGCACAAT-3&#39;, and the primers used for fibronectin were forward 5&#39;-TCTGGGAAATGGAAAAGGGGAATGG-3&#39; and reverse 5&#39;-CACTGAAGCAGGTTTCCTCGGTTGT-3&#39;.</li>
	</ol>
	</li>
	<li>Perform immunohistochemistry as described below.
	<ol>
		<li>Dehydrate the left lung, embed it, and slice it with a paraffin slicer to a thickness of 4 &#181;m.</li>
		<li>Place the tissue sections onto slides and bake the slides in an oven at 65-70 &#176; C for 30 min to 1 h. Dewax the slides with a decreasing percentage of alcohol (i.e., 100%, 95%, 90%, 80%, and 70% alcohol) for 5 min.</li>
		<li>Stain the slides in hematoxylin dye solution (analytically pure) for 5 min. Then, wash the slides with tap water. Soak the slides in 1% hydrochloric acid alcohol for 3 s, wash off the floating color, and soak in flowing water for 5 min. The sections will turn blue.</li>
		<li>Immerse in eosin solution for 10 s to 1 min (determine the dyeing time according to the color), wash with tap water, and place in 70%, 80%, 95%, 100%, and 100% alcohol, respectively, for 5 min each. Then place, the slides in xylene I and xylene II solutions for 3 min. After drying, observe and take photos under the vertical microscope with neutral adhesive sealing film.</li>
		<li>Perform Ashcroft scoring on the sections to indicate the severity of pulmonary fibrosis10. Perform statistical analysis of the data using a t-test of two independent samples.</li>
	</ol>
	</li>
</ol>

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The authors have no competing financial interests.

This study provides an effective method to deplete, isolate, culture, and transfer macrophages, which can help in studying the mechanisms of pulmonary fibrosis in mice. There are many methods for mouse macrophage depletion, such as tracheal administration, tail vein injection, and nasal inhalation11. This study optimized the nasal inhalation method, which is simple to operate and can effectively deplete pulmonary macrophages8,9. After the ...

An erratum was issued for:&#160;<a href="https://www.jove.com/t/64742">Adoptive Transfer of IL-33-Stimulated Macrophages into Bleomycin-Induced Mouse Models to Study Their Effect on Idiopathic Pulmonary Fibrosis In Vivo</a>. The Protocol section was updated.
Step 2.1 of the Protocol was updated from:
Anesthetize the host mouse with 3% isoflurane, and then euthanize it by cervical dislocation. Disinfect the skin of the euthanized mouse with 75% alcohol and iodine. Use scissors to cut through the skin and expose the cardiopulmonary tissue
to:
Anesthetize the host mouse&#160;with an intraperitoneal injection of Ketamine (120 mg/kg) and Xylazine (16 mg/kg). Confirm the depth of anesthesia via loss of the toe pinch reflex. Apply veterinary ointment to both eyes to prevent dryness under anesthesia. Then, disinfect the skin of the anesthetized mouse with 75% alcohol and iodine. Use scissors to cut through the skin and expose the cardiopulmonary tissue

An erratum was issued for:&#160;<a href="https://www.jove.com/t/64742">Adoptive Transfer of IL-33-Stimulated Macrophages into Bleomycin-Induced Mouse Models to Study Their Effect on Idiopathic Pulmonary Fibrosis In Vivo</a>. The Protocol section was updated.

Erratum: Adoptive Transfer of IL-33-Stimulated Macrophages into Bleomycin-Induced Mouse Models to Study Their Effect on Idiopathic Pulmonary Fibrosis In Vivo

Idiopathic pulmonary fibrosis (IPF) is a diffuse pulmonary inflammatory disease caused by many factors1. In the cytokine microenvironment of the Th1 and Th2 immune response, macrophages can be polarized into classically activated macrophages (M1) and alternatively activated macrophages (M2). Lipopolysaccharides (LPS) or the cytokine IFN- &#947; induce M1 macrophages to polarize and produce pro-inflammatory cytokines, including iNOS, IL-1, IL-6, TNF-&#945;, and IL-12. In contrast, the type II cytokines IL-4 and IL-13 drive the polarization of M2 macrophages, which can produce different fibroblast growth-promoting factors, such as TGF-&#946; and PDGF, that promote pulmonary fibrosis2. The pathological process of IPF is accompanied by macrophage activation and infiltration. IPF mediates injury repair, inflammation, and fibrosis through the release of cytokines3. As only limited therapeutic options are available, exploring the molecular pathological mechanisms of IPF holds great significance for developing new strategies for IPF prevention and treatment. Previous studies by our group and other researchers4,5 have confirmed the increased release of IL-33 in IPF patients and in mouse models with bleomycin (BLM)-induced IPF. IL-33 is released by the epithelial and endothelial cells during fibrosis and is involved in macrophage activation, resulting in the abnormal proliferation of fibroblasts, leukocyte infiltration, and the eventual loss of lung function5. The current protocol describes the adoptive transfer of IL-33-stimulated interstitial macrophages (IMs) into the alveoli as a means to study IPF development in mouse models. Here, IMs were isolated from the lung tissue of host mice, cultured in vitro, stimulated with IL-33 for 24 h, and then adoptively transferred into the alveoli of recipient mice by tracheal injection. The direct collection of stimulated mouse macrophages and their adoptive transfer into the recipient alveoli was found to aggravate the degree of pulmonary fibrosis and can more clearly illustrate the influence of stimulating factors on fibrosis compared to the previous studies6. The technique described in this paper can enable researchers to explore the function of macrophages stimulated by potential cytokines in the development of IPF.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>&#160;DMEM</td>
			<td>Life technologies Biotechnology,USA</td>
			<td>1508012</td>
			<td></td>
		</tr>
		<tr>
			<td>Arterial indwelling needle</td>
			<td>B Braun Melsingen AG,Germany</td>
			<td>21G15G8393</td>
			<td></td>
		</tr>
		<tr>
			<td>BD&#160;Accuri&#160;C6 Plus</td>
			<td>Becton Dickinson,USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bleomycin</td>
			<td>Biotang, USA</td>
			<td>Ab9465</td>
			<td></td>
		</tr>
		<tr>
			<td>Carbon dioxide incubator</td>
			<td>Thermo Forma, USA</td>
			<td>Thermo Forma370</td>
			<td></td>
		</tr>
		<tr>
			<td>CD11b</td>
			<td>R&#38;D Systems,USA</td>
			<td>1124F</td>
			<td></td>
		</tr>
		<tr>
			<td>CD11c</td>
			<td>R&#38;D Systems,USA</td>
			<td>N418</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell culture dish</td>
			<td>Thermo Forma, USA</td>
			<td>174926</td>
			<td></td>
		</tr>
		<tr>
			<td>Clodronate liposomes&#160;</td>
			<td>Clodronate liposomes,Netherlands</td>
			<td>CI-150-150</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagenase A</td>
			<td>Sigma-Aldrich, USA</td>
			<td>10103578001</td>
			<td></td>
		</tr>
		<tr>
			<td>F4/80</td>
			<td>R&#38;D Systems,USA</td>
			<td>521204</td>
			<td></td>
		</tr>
		<tr>
			<td>Falcon Cell Strainer</td>
			<td>Becton,Dickinson and Company, USA</td>
			<td>352340</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal bovine serum (FBS)</td>
			<td>Life technologies,USA</td>
			<td>1047571</td>
			<td></td>
		</tr>
		<tr>
			<td>Hematoxylin Eosin&#160;</td>
			<td>Nanjing Jiancheng Technology,China</td>
			<td>06-570</td>
			<td></td>
		</tr>
		<tr>
			<td>LightCycler 480 PCR detection system</td>
			<td>Roche, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Murine recombinant factor IL-33</td>
			<td>Peprotech, USA</td>
			<td>210-33</td>
			<td></td>
		</tr>
		<tr>
			<td>Nikon microscope</td>
			<td>Nikon Corporation, Japan</td>
			<td>941185</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin, streptomycin</td>
			<td>Life technologies,USA</td>
			<td>877113</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate buffer (PBS)</td>
			<td>Guangdong Huankai Microbial Technology ,China</td>
			<td>1535882</td>
			<td></td>
		</tr>
		<tr>
			<td>RBC lysis buffer</td>
			<td>Beyotime Biotechnology Company,China</td>
			<td>C3702</td>
			<td></td>
		</tr>
		<tr>
			<td>RNA Isolater</td>
			<td>Vazyme company,China</td>
			<td>R401-01-AA</td>
			<td>Total RNA extraction reagent</td>
		</tr>
		<tr>
			<td>RWD Inhalation Anesthesia Machine</td>
			<td>Shenzhen Rayward Life Technology ,China</td>
			<td>R500</td>
			<td></td>
		</tr>
		<tr>
			<td>Semi-automatic paraffin slicer</td>
			<td>Leica, Germany</td>
			<td>LeicaRM2245</td>
			<td></td>
		</tr>
		<tr>
			<td>SYBR Premix Ex Taq</td>
			<td>Takara, Japan</td>
			<td>410800</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin 0.25%</td>
			<td>Life Technologies, USA</td>
			<td>1627172</td>
			<td></td>
		</tr>
	</tbody>
</table>

adoptive transfer of il-33-stimulated macrophages into bleomycin-induced mouse models to study their effect on idiopathic pulmonary fibrosis in vivo

The inflammatory response caused by early lung injury is one of the important causes of the development of idiopathic pulmonary fibrosis (IPF), which is accompanied by the activation of inflammatory cells such as macrophages and neutrophils, as well as the release of inflammatory factors including TNF-&#945;, IL-1&#946;, and IL-6. Early inflammation caused by activated pulmonary interstitial macrophages (IMs) in response to IL-33 stimulation is known to play a vital role in the pathological process of IPF. This protocol describes the adoptive transfer of IMs stimulated by IL-33 into the lungs of mice to study IPF development. It involves the isolation and culture of primary IMs from host mouse lungs, followed by the adoptive transfer of stimulated IMs into the alveoli of bleomycin (BLM)-induced IPF recipient mice (which have been previously depleted of alveolar macrophages by treatment with clodronate liposomes), and the pathological evaluation of those mice. The representative results show that the adoptive transfer of IL-33-stimulated macrophages aggravates pulmonary fibrosis in mice, suggesting that the establishment of the macrophage adoptive transfer experiment is a good technical means to study IPF pathology.

The protocol used here is summarized in the flowchart in Figure 1. The inhalation of clodronate liposomes through the nose (Figure 2) was used to deplete the pulmonary macrophages of adult C57BL/6 mice, and this produced a good recipient mouse model. Pulmonary IMs were isolated from another untreated (host) mouse (Figure 3A,B) and cultured in vitro. The isolated macrophages were stimulated with IL-33 for 24...

Watch this Scientific Journal Video about Adoptive Transfer of IL-33-Stimulated Macrophages into Bleomycin-Induced Mouse Models to Study Their Effect on Idiopathic Pulmonary Fibrosis In Vivo at JoVE.c

Adoptive Transfer of IL-33-Stimulated Macrophages into Bleomycin-Induced Mouse Models to Study Their Effect on Idiopathic Pulmonary Fibrosis In Vivo

This protocol describes the isolation of pulmonary interstitial macrophages (IMs) and their adoptive transfer after IL-33 stimulation of the lung alveoli in a mouse model, which can facilitate the in vivo study of idiopathic pulmonary fibrosis (IPF).

Adoptive Transfer of IL-33-Stimulated Macrophages into Bleomycin-Induced Mouse Models to Study Their Effect on Idiopathic Pulmonary Fibrosis In Vivo

The inflammatory response caused by early lung injury is one of the important causes of the development of idiopathic pulmonary fibrosis (IPF), which is ...

adoptive-transfer-il-33-stimulated-macrophages-into-bleomycin-induced

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2.0K Views.  Jiangnan University. This protocol describes the isolation of pulmonary interstitial macrophages (IMs) and their adoptive transfer after IL-33 stimulation of the lung alveoli in a mouse model, which can facilitate the in vivo study of idiopathic pulmonary fibrosis (IPF).

Video: Adoptive Transfer of IL-33-Stimulated Macrophages into Bleomycin-Induced Mouse Models to Study Their Effect on Idiopathic Pulmonary Fibrosis In Vivo

Experimental Metastasis and CTL Adoptive Transfer Immunotherapy Mouse Model

Experimental metastasis mouse model is a simple and yet physiologically relevant metastasis model. The tumor cells are injected intravenously (i.v) into mouse tail veins and colonize in the lungs, thereby, resembling the last steps of tumor cell spontaneous metastasis: survival in the circulation, extravasation and colonization in the distal organs. From a therapeutic point of view, the experimental metastasis model is the simplest and ideal model since the target of therapies is often the end point of metastasis: established metastatic tumor in the distal organ. In this model, tumor cells are injected i.v into mouse tail veins and allowed to colonize and grow in the lungs. Tumor-specific CTLs are then injected i.v into the metastases-bearing mouse. The number and size of the lung metastases can be controlled by the number of tumor cells to be injected and the time of tumor growth. Therefore, various stages of metastasis, from minimal metastasis to extensive metastasis, can be modeled. Lung metastases are analyzed by inflation with ink, thus allowing easier visual observation and quantification.

An experimental lung metastasis and CTL immunotherapy mouse model for analysis of tumor cells-T cell interaction in vivo.

Experimental metastasis mouse model is a simple and yet physiologically relevant metastasis model. The tumor cells are injected intravenously (i.v) into ...

Overcoming Unresponsiveness in Experimental Autoimmune Encephalomyelitis (EAE) Resistant Mouse Strains by Adoptive Transfer and Antigenic Challenge

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease of the central nervous system (CNS) and has been used as an animal model for study of the human demyelinating disease, multiple sclerosis (MS). EAE is characterized by pathologic infiltration of mononuclear cells into the CNS and by clinical manifestation of paralytic disease. Similar to MS, EAE is also under genetic control in that certain mouse strains are susceptible to disease induction while others are resistant. Typically, C57BL/6 (H-2b) mice immunized with myelin basic protein (MBP) fail to develop paralytic signs. This unresponsiveness is certainly not due to defects in antigen processing or antigen presentation of MBP, as an experimental protocol described here had been used to induce severe EAE in C57BL/6 mice as well as other reputed resistant mouse strains. In addition, encephalitogenic T cell clones from C57BL/6 and Balb/c mice reactive to MBP had been successfully isolated and propagated.
The experimental protocol involves using a cellular adoptive transfer system in which MBP-primed (200 &mu;g/mouse) C57BL/6 donor lymph node cells are isolated and cultured for five days with the antigen to expand the pool of MBP-specific T cells. At the end of the culture period, 50 million viable cells are transferred into naive syngeneic recipients through the tail vein. Recipient mice so treated normally do not develop EAE, thus reaffirming their resistant status, and they can remain normal indefinitely. Ten days post cell transfer, recipient mice are challenged with complete Freund adjuvant (CFA)-emulsified MBP in four sites in the flanks. Severe EAE starts to develop in these mice ten to fourteen days after challenge. Results showed that the induction of disease was antigenic specific as challenge with irrelevant antigens did not induce clinical signs of disease. Significantly, a titration of the antigen dose used to challenge the recipient mice showed that it could be as low as 5 &mu;g/mouse. In addition, a kinetic study of the timing of antigenic challenge showed that challenge to induce disease was effective as early as 5 days post antigenic challenge and as long as over 445 days post antigenic challenge. These data strongly point toward the involvement of a "long-lived" T cell population in maintaining unresponsiveness. The involvement of regulatory T cells (Tregs) in this system is not defined.

Overcoming Unresponsiveness in Experimental Autoimmune Encephalomyelitis EAE Resistant Mouse Strains by Adoptive Transfer and Antigenic Challenge

Certain mouse strains are able to resist induction of experimental autoimmune encephalomyelitis (EAE) with myelin basic protein. Described here is a simple immunization protocol that reverses the unresponsiveness and induces paralytic disease in several typical EAE resistant mouse stains.

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease of the central nervous system (CNS) and has been used as an animal model for ...

Isolation, Purification and Labeling of Mouse Bone Marrow Neutrophils for Functional Studies and Adoptive Transfer Experiments

Neutrophils are critical effector cells of the innate immune system. They are rapidly recruited at sites of acute inflammation and exert protective or pathogenic effects depending on the inflammatory milieu. Nonetheless, despite the indispensable role of neutrophils in immunity, detailed understanding of the molecular factors that mediate neutrophils' effector and immunopathogenic effects in different infectious diseases and inflammatory conditions is still lacking, partly because of their short half life, the difficulties with handling of these cells and the lack of reliable experimental protocols for obtaining sufficient numbers of neutrophils for downstream functional studies and adoptive transfer experiments. Therefore, simple, fast, economical and reliable methods are highly desirable for harvesting sufficient numbers of mouse neutrophils for assessing functions such as phagocytosis, killing, cytokine production, degranulation and trafficking. To that end, we present a reproducible density gradient centrifugation-based protocol, which can be adapted in any laboratory to isolate large numbers of neutrophils from the bone marrow of mice with high purity and viability. Moreover, we present a simple protocol that uses CellTracker dyes to label the isolated neutrophils, which can then be adoptively transferred into recipient mice and tracked in several tissues for at least 4 hr post-transfer using flow cytometry. Using this approach, differential labeling of neutrophils from wild-type and gene-deficient mice with different CellTracker dyes can be successfully employed to perform competitive repopulation studies for evaluating the direct role of specific genes in trafficking of neutrophils from the blood into target tissues in vivo.

We describe a protocol for isolation and purification of neutrophils from mouse bone marrow by density gradient centrifugation and for neutrophil labeling using CellTracker dyes. This represents a simple, fast, reproducible and economical method for obtaining large numbers of neutrophils for downstream functional studies or adoptive transfer and tracking experiments.

Neutrophils are critical effector cells of the innate immune system. They are rapidly recruited at sites of acute inflammation and exert protective or ...

Use of Shigella flexneri to Study Autophagy-Cytoskeleton Interactions

Shigella flexneri is an intracellular pathogen that can escape from phagosomes to reach the cytosol, and polymerize the host actin cytoskeleton to promote its motility and dissemination. New work has shown that proteins involved in actin-based motility are also linked to autophagy, an intracellular degradation process crucial for cell autonomous immunity. Strikingly, host cells may prevent actin-based motility of S. flexneri by compartmentalizing bacteria inside &#8216;septin cages&#8217; and targeting them to autophagy. These observations indicate that a more complete understanding of septins, a family of filamentous GTP-binding proteins, will provide new insights into the process of autophagy. This report describes protocols to monitor autophagy-cytoskeleton interactions caused by S. flexneri in vitro using tissue culture cells and in vivo using zebrafish larvae. These protocols enable investigation of intracellular mechanisms that control bacterial dissemination at the molecular, cellular, and whole organism level.

Use of Shigella flexneri to Study Autophagy-Cytoskeleton Interactions

To counteract pathogen dissemination, host cells reorganize their cytoskeleton to compartmentalize bacteria and induce autophagy. Using Shigella infection of tissue culture cells, host and pathogen determinants underlying this process are identified and characterized. Using zebrafish models of Shigella infection, the role of discovered molecules and mechanisms are investigated in vivo.

Shigella flexneri is an intracellular pathogen that can escape from phagosomes to reach the cytosol, and polymerize the host actin cytoskeleton to promote ...

Induction of Murine Intestinal Inflammation by Adoptive Transfer of Effector CD4+CD45RBhigh T Cells into Immunodeficient Mice

There are many different animal models available for studying the pathogenesis of human inflammatory bowel diseases (IBD), each with its own advantages and disadvantages. We describe here an experimental colitis model that is initiated by adoptive transfer of syngeneic splenic CD4+CD45RBhigh T cells into T and B cell deficient recipient mice. The CD4+CD45RBhigh T cell population that largely consists of na&#239;ve effector cells is capable of inducing chronic intestinal inflammation, closely resembling key aspects of human IBD. This method can be manipulated to study aspects of disease onset and progression. Additionally it can be used to study the function of innate, adaptive, and regulatory immune cell populations, and the role of environmental exposures, i.e., the microbiota, in intestinal inflammation. In this article we illustrate the methodology for inducing colitis with a step-by-step protocol. This includes a video demonstration of key technical aspects required to successfully develop this murine model of experimental colitis for research purposes.

Induction of Murine Intestinal Inflammation by Adoptive Transfer of Effector CD4+CD45RBhigh T Cells into Immunodeficient Mice

Here, we present a protocol to induce colonic inflammation in mice by adoptive transfer of syngeneic CD4+CD45RBhigh T cells into T and B cell deficient recipients. Clinical and histopathological features mimic human inflammatory bowel diseases. This method allows the study of the initiation of colonic inflammation and progression of disease.

There are many different animal models available for studying the pathogenesis of human inflammatory bowel diseases (IBD), each with its own advantages ...

Generation of Lymphocytic Microparticles and Detection of their Proapoptotic Effect on Airway Epithelial Cells

Interest in the biological roles of cell membrane&#8211;derived vesicles in cell&#8211;cell communication has increased in recent years. Microparticles (MPs) are one such type of vesicles, ranging in diameter from 0.1 &#956;m to 1 &#956;m, and typically shed from the plasma membrane of eukaryotic cells undergoing activation or apoptosis. Here we describe the generation of T lymphocyte&#8211;derived microparticles (LMPs) from apoptotic CEM T cells stimulated with actinomycin D. LMPs are isolated through a multistep differential centrifugation process and characterized using flow cytometry. This protocol also presents an in situ cell death detection method for demonstrating the proapoptotic effect of LMPs on bronchial epithelial cells derived from mouse primary respiratory bronchial tissue explants. Methods described herein provide a reproducible procedure for isolating abundant quantities of LMPs from apoptotic lymphocytes in vitro. LMPs derived in this manner can be used to evaluate the characteristics of various disease models, and for pharmacology and toxicology testing. Given that the airway epithelium offers a protective physical and functional barrier between the external environment and underlying tissue, use of bronchial tissue explants rather than immortalized epithelial cell lines provides an effective model for investigations requiring airway tract tissue.

Cell membrane&#8211;shed microparticles (MPs) are active biological vesicles that can be isolated and their pathophysiological effects investigated in various models. Here we describe a method for generating MPs derived from T lymphocytes (LMPs) and for demonstrating their proapoptotic effect on airway epithelial cells.

Interest in the biological roles of cell membrane&#8211;derived vesicles in cell&#8211;cell communication has increased in recent years. Microparticles ...

Intranasal Administration of Recombinant Influenza Vaccines in Chimeric Mouse Models to Study Mucosal Immunity

Vaccines are one of the greatest achievements of mankind, and have saved millions of lives over the last century. Paradoxically, little is known about the physiological mechanisms that mediate immune responses to vaccines perhaps due to the overall success of vaccination, which has reduced interest into the molecular and physiological mechanisms of vaccine immunity. However, several important human pathogens including influenza virus still pose a challenge for vaccination, and may benefit from immune-based strategies. 
Although influenza reverse genetics has been successfully applied to the generation of live-attenuated influenza vaccines (LAIVs), the addition of molecular tools in vaccine preparations such as tracer components to follow up the kinetics of vaccination in vivo, has not been addressed. In addition, the recent generation of mouse models that allow specific depletion of leukocytes during kinetic studies has opened a window of opportunity to understand the basic immune mechanisms underlying vaccine-elicited protection. Here, we describe how the combination of reverse genetics and chimeric mouse models may help to provide new insights into how vaccines work at physiological and molecular levels, using as example a recombinant, cold-adapted, live-attenuated influenza vaccine (LAIV). We utilized laboratory-generated LAIVs harboring cell tracers as well as competitive bone marrow chimeras (BMCs) to determine the early kinetics of vaccine immunity and the main physiological mechanisms responsible for the initiation of vaccine-specific adaptive immunity. In addition, we show how this technique may facilitate gene function studies in single animals during immune responses to vaccines. We propose that this technique can be applied to improve current prophylactic strategies against pathogens for which urgent medical countermeasures are needed, for example influenza, HIV, Plasmodium, and hemorrhagic fever viruses such as Ebola virus.

There is an overall lack of knowledge about how vaccines work. Here we propose the combined use of reverse genetics and bone marrow chimeric mice to gain insight into the early host immune responses to vaccines with a special focus on dendritic cells and T cell immunity.

Vaccines are one of the greatest achievements of mankind, and have saved millions of lives over the last century. Paradoxically, little is known about the ...

Intra-tracheal Administration of Haemophilus influenzae in Mouse Models to Study Airway Inflammation

Here, we describe a detailed procedure to efficiently and directly deliver Haemophilus influenzae into the lower respiratory tracts of mice. We demonstrate the procedure for preparing H. influenzae inoculum, intra-tracheal instillation of H. influenzae into the lung, collection of broncho-alveolar lavage fluid (BALF), analysis of immune cells in the BALF, and RNA isolation for differential gene expression analysis. This procedure can be used to study the lung inflammatory response to any bacteria, virus or fungi. Direct tracheal instillation is mostly preferred over intranasal or aerosol inhalation procedures because it more efficiently delivers the bacterial inoculum into the lower respiratory tract with less ambiguity.

Intra-tracheal Administration of Haemophilus influenzae in Mouse Models to Study Airway Inflammation

We demonstrate the procedure for intra-tracheal inoculation of Haemophilus influenzae into the lower respiratory tracts of mice. This is a very useful tool to study signaling pathways that regulate airway inflammation in mouse models.

Here, we describe a detailed procedure to efficiently and directly deliver Haemophilus influenzae into the lower respiratory tracts of mice. We ...

Legionella pneumophila Outer Membrane Vesicles: Isolation and Analysis of Their Pro-inflammatory Potential on Macrophages

Bacteria are able to secrete a variety of molecules via various secretory systems. Besides the secretion of molecules into the extracellular space or directly into another cell, Gram-negative bacteria can also form outer membrane vesicles (OMVs). These membrane vesicles can deliver their cargo over long distances, and the cargo is protected from degradation by proteases and nucleases. 
Legionella pneumophila (L. pneumophila) is an intracellular, Gram-negative pathogen that causes a severe form of pneumonia. In humans, it infects alveolar macrophages, where it blocks lysosomal degradation and forms a specialized replication vacuole. Moreover, L. pneumophila produces OMVs under various growth conditions. To understand the role of OMVs in the infection process of human macrophages, we set up a protocol to purify bacterial membrane vesicles from liquid culture. The method is based on differential ultracentrifugation. The enriched OMVs were subsequently analyzed with regard to their protein and lipopolysaccharide (LPS) amount and were then used for the treatment of a human monocytic cell line or murine bone marrow-derived macrophages. The pro-inflammatory responses of those cells were analyzed by enzyme-linked immunosorbent assay. Furthermore, alterations in a subsequent infection were analyzed. To this end, the bacterial replication of L. pneumophila in macrophages was studied by colony-forming unit assays. 
Here, we describe a detailed protocol for the purification of L. pneumophila OMVs from liquid culture by ultracentrifugation and for the downstream analysis of their pro-inflammatory potential on macrophages.

Legionella pneumophila Outer Membrane Vesicles: Isolation and Analysis of Their Pro-inflammatory Potential on Macrophages

Here, we describe the purification of Legionella pneumophila (L. pneumophila) outer membrane vesicles (OMVs) from liquid cultures. These purified vesicles are then used for the treatment of macrophages to analyze their pro-inflammatory potential.

Bacteria are able to secrete a variety of molecules via various secretory systems. Besides the secretion of molecules into the extracellular space or ...

An IL-8 Transiently Transgenized Mouse Model for the In Vivo Long-term Monitoring of Inflammatory Responses

Airway inflammation is often associated with bacterial infections and represents a major determinant of lung disease. The in vivo determination of the pro-inflammatory capabilities of various factors is challenging and requires terminal procedures, such as bronchoalveolar lavage and the removal of lungs for in situ analysis, precluding longitudinal visualization in the same mouse. Here, lung inflammation is induced through the intratracheal instillation of Pseudomonas aeruginosa culture supernatant (SN) in transiently transgenized mice expressing the luciferase reporter gene under the control of a heterologous IL-8 bovine promoter. Luciferase expression in the lung is monitored by in vivo bioluminescent image (BLI) analysis over a 2.5- to 48-h timeframe following the instillation. The procedure can be repeated multiple times within 2 - 3 months, thus permitting the evaluation of the inflammatory response in the same mice without the need to terminate the animals. This approach permits the monitoring of pro- and anti-inflammatory factors acting in the lung in real time and appears suitable for functional and pharmacological studies.

An IL-8 Transiently Transgenized Mouse Model for the In Vivo Long-term Monitoring of Inflammatory Responses

The method described here allows for the visualization of IL-8 promoter-dependent inflammation activation in the lungs of mice through non-invasive bioluminescence imaging (BLI). The same animal can be subjected to BLI multiple times for up to two months from the time of delivery of the luciferase reporter construct.

Airway inflammation is often associated with bacterial infections and represents a major determinant of lung disease. The in vivo determination of the ...