We thank Clare Prendergast for assistance with editing the manuscript. DKN is supported by a research grant (#2095) from the Flinn Foundation and TM is supported by grants from National Institutes of Health (R01HL056643 and R01HL092514). DKN developed the methods, designed the study and wrote the manuscript; OM assisted with animal studies and clinical sample procurement; SB assisted with Flow cytometric analysis and cell sorting; TM supervised the studies and reviewed the manuscript.

All methods described here have been approved by the Institutional Animal Care and Use Committee (IACUC) and the Institutional Review Board (IRB) at St Joseph&#39;s Hospital and Medical Center.
1. Isolation of AMs from Murine Bronchoalveolar Lavage (BAL) Fluid
<ol>
	<li>Anaesthetize an eight-week-old C57BL/6 mouse with ketamine (87.5 mg/kg body weight) and xylazine (12.5 mg/kg body weight) cocktail via an intraperitoneal injection. Proceed when mouse attains surgical anesthesia with loss of ...

<ol>
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The authors have no conflicts of interest to declare.

AMs are long-living lung-resident macrophages that populate the lungs beginning at birth and enduring over the entire life span26. Their roles in pulmonary physiology7 and pathology12 and their potential to predict of pulmonary autoimmunity24 have been recognized. Because AMs have a long-term presence in lungs11,27 and because they are involved in activation and progre...

The lung microenvironment is a uniquely complex ecosystem with an elaborate air conduit and vasculature. The inhaled air travels through the trachea and through numerous branches of bronchi and bronchioles before reaching the alveoli, where the blood-air gas exchange occurs. Due to direct interaction with the atmosphere, the respiratory surface requires protection from the potentially harmful effects of airborne particles and pollutants. A number of physical, chemical, and immunologic barriers protect the lungs. Notably, deployment of phagocytes at the respiratory surface serves an important first-line defense system. Alveolar macrophages (AMs) are one type of lung-resident phagocytes, and they make up the vast majority of the lung macrophage pool. As their name suggests, AMs are primarily localized to the alveolar lumen and occur as sessile cells that constantly sample the ambient atmosphere and communicate with the alveolar epithelium1. In steady state lungs, more than 95% of the phagocytes in the alveolar space are AMs2, whose composition may alter due to inflammation, infection, or chronic exposure to pollutants.
AMs participate in a wide range of functions that may be local to the lungs and/or of systemic importance. For example, AMs are essential in the development and the optimal functioning of lungs; immune surveillance; and clearance of cellular debris, invading pathogens, and inhaled particles3,4,5,6,7. Targeted depletion of AMs is known to impair clearance of respiratory viruses and bacteria4,8. Besides their role as phagocytes and a first-line defenders of pulmonary homeostasis, AMs are known to function as antigen-presenting cells in eliciting T cell immunity9, potentiating the efficacy of intranasal vaccine10 and influencing lung-restricted autoimmunity after lung transplantation11,12. Deficiency in AM function has been linked to pulmonary alveolar proteinosis (PAP), a condition resulting from a genetic mutation, malignancy or infection that impairs clearance of pulmonary surfactants13,14. Transplantation of AMs is now being explored as a therapeutic approach for treatment of PAP 15,16.
AMs are known to originate during embryogenesis and to persist in the lungs throughout life without being replaced by circulating leukocytes2,17. Although, AM turnover is undetectable in homeostatic lungs, varying levels of AM turnover have been reported in certain clinical conditions including infection by the influenza virus4, myeloablative irradiation18, exposure to endotoxin19, and old age20. AMs are believed to self-renew via a low-grade proliferation17,21, but some recent studies claim that monocytes can give rise to a population of intravascular lung macrophages22,23 under experimental conditions, but functionality of these newly converted pulmonary macrophages have yet to be defined in lung diseases. Furthermore, understanding the threshold of stimulus in the context of AM activation is a potentially interesting area, as the lung attempts to preserve an equilibrium between the inflammatory signals and the immunoregulatory machinery.
The physiologic or pathologic alterations that lead to loss of immune regulation are important to evaluate in various clinical settings (e.g., respiratory infections, inflammatory lung disease and fibrotic lung disease). Nevertheless, AMs are increasingly recognized as indicators or even determinants of pulmonary health11,24. Currently, there are no unified protocols available for harvesting, characterizing, and/or maintaining AMs from humans and preclinical murine models. Lack of a consensus on AM precursors and phenotypes, and absence of a detailed methodology had been the major roadblock in deciphering role(s) of AM in pulmonary health and disease. The following protocol offers a definitive identification, isolation, and in vitro culture strategy that will greatly advance the understanding of AM behavior and facilitate AM-targeted diagnostic and therapeutic studies.

<table border="0" cellpadding="0" cellspacing="0" width="910">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Non-enzymatic cell dissociating solution</td>
			<td style="width:223px;">Millipore-Sigma</td>
			<td style="width:220px;">C5789</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Puralube Vet Ointment</td>
			<td style="width:223px;">Dechra</td>
			<td>620300</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">22G Catheter&#160;</td>
			<td style="width:223px;">Terumo Medical Products</td>
			<td>SR-OX2225CA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">4-0 Non-absorbable silk braided suture&#160;</td>
			<td style="width:223px;">Kent Scientific</td>
			<td>SUT-15-2</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dulbecco&#8217;s phosphate buffered saline&#160;</td>
			<td style="width:223px;">Corning</td>
			<td style="width:220px;">21-031-CM</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mouse Fc block&#160;</td>
			<td>BD Biosciences</td>
			<td>553142</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Lysis buffer (PureLink RNA Kit)</td>
			<td>Thermo Fisher Scientific&#160;</td>
			<td>12183018A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">b-Mercaptoethanol&#160;</td>
			<td style="width:223px;">Millipore-Sigma</td>
			<td>M6250&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">FACSAria II cell sorter&#160;</td>
			<td style="width:223px;">BD Biosciences</td>
			<td style="width:220px;">644832</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ketamine&#160; (Ketathesia)</td>
			<td style="width:223px;">Henry Schein</td>
			<td style="width:220px;">56344</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Xylazine&#160; (AnaSed)</td>
			<td style="width:223px;">Akorn</td>
			<td style="width:220px;">139-236</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">RPMI 1640</td>
			<td style="width:223px;">Corning</td>
			<td style="width:220px;">10-040-CM</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DMEM</td>
			<td style="width:223px;">Corning</td>
			<td style="width:220px;">10-017-CM</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Liberase TL&#160;</td>
			<td style="width:223px;">Millipore-Sigma</td>
			<td style="width:220px;">5401020001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DNase I</td>
			<td style="width:223px;">Millipore-Sigma</td>
			<td>AMPD1-1KT</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">100&#956;m cell strainer&#160;</td>
			<td style="width:223px;">Corning</td>
			<td>352360</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Human Fc block</td>
			<td>BD Biosciences</td>
			<td>564220</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">EDTA</td>
			<td style="width:223px;">Corning</td>
			<td>46-034-CI</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Countess II Automated Cell Counter</td>
			<td>Thermo Fisher Scientific&#160;</td>
			<td>AMQAX1000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Trypan Blue Solution</td>
			<td>Thermo Fisher Scientific&#160;</td>
			<td>15250061</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">HEPES</td>
			<td style="width:223px;">Corning</td>
			<td>25-060-CI</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Fetal Bovine Serum</td>
			<td>Atlanta Biologicals</td>
			<td>S11150H</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">L-929 cell line</td>
			<td>American Type Culture Collection</td>
			<td>ATCC,&#160;CCL-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Penicillin/Streptomycin&#160;</td>
			<td style="width:223px;">Corning</td>
			<td>30-002-CI</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium Pyruvate</td>
			<td style="width:223px;">Corning</td>
			<td>25-000-CI</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">T25 Tissue culture flask</td>
			<td>Thermo Fisher Scientific&#160;</td>
			<td>156367</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">60 mm culture dish&#160;</td>
			<td style="width:223px;">Millipore-Sigma</td>
			<td>CLS3261</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">15 mL Conical tube&#160;</td>
			<td style="width:223px;">Corning</td>
			<td style="width:220px;">352097</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">50 mL Conical tube&#160;</td>
			<td style="width:223px;">Corning</td>
			<td>352098</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">LSRFortessa cell analyzer</td>
			<td>BD Biosciences</td>
			<td>657669</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">FlowJo</td>
			<td style="width:223px;">FlowJo</td>
			<td>v10.4</td>
			<td>Analysis Software</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-CD45 (Mouse)</td>
			<td style="width:223px;">Biolegend</td>
			<td>147709</td>
			<td>Clone I3/2.3, FITC conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-CD11b (Mouse)</td>
			<td style="width:223px;">Biolegend</td>
			<td>101228</td>
			<td>Clone M1/70, PerCP/Cy5.5 conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-CD11c (Mouse)</td>
			<td>BD Biosciences</td>
			<td>565452</td>
			<td>Clone N418, BV 421 conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-I-Ab (Mouse)</td>
			<td style="width:223px;">Biolegend</td>
			<td>116420</td>
			<td>Clone AF6-120.1, PE/Cy7 conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-Siglec-F (Mouse)</td>
			<td style="width:223px;">BD Biosciences</td>
			<td>562757</td>
			<td>Clone E50-2440, PE-CF594 conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-Siglec-H (Mouse)</td>
			<td style="width:223px;">Biolegend</td>
			<td>129605</td>
			<td>Clone 551, PE conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-F4/80 (Mouse)</td>
			<td style="width:223px;">Biolegend</td>
			<td>123118</td>
			<td>Clone BM8, APC/Cy7 conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-Ly-6C (Mouse)</td>
			<td style="width:223px;">Biolegend</td>
			<td>128035</td>
			<td>Clone HK1.4, BV605 conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-CD64 (Mouse)</td>
			<td style="width:223px;">Biolegend</td>
			<td>139311</td>
			<td>Clone X54-5/7.1, BV711 conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-CD24 (Mouse)</td>
			<td style="width:223px;">BD Biosciences</td>
			<td>563115</td>
			<td>Clone M1/69, BV510 conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-CD103 (Mouse)</td>
			<td style="width:223px;">BD Biosciences</td>
			<td>745305</td>
			<td>Clone OX-62, BV650 conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-CD317 (Mouse)</td>
			<td style="width:223px;">Biolegend</td>
			<td>127015</td>
			<td>Clone 927, APC conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-CXCR1 (Mouse)</td>
			<td style="width:223px;">Biolegend</td>
			<td>149029</td>
			<td>Clone SA011F11, BV785 conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-CD45 (Human)</td>
			<td style="width:223px;">Biolegend</td>
			<td>304017</td>
			<td>Clone HI30, AF488 conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-CD11b (Human)</td>
			<td style="width:223px;">Biolegend</td>
			<td>101216</td>
			<td>Clone M1/70, PE/Cy7 conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-HLA-DR (Human)</td>
			<td style="width:223px;">Biolegend</td>
			<td>307618</td>
			<td>Clone L243, APC/Cy7 conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-CD169 (Human)</td>
			<td style="width:223px;">Biolegend</td>
			<td>346008</td>
			<td>Clone 7-239, APC conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-CD206 (Human)</td>
			<td style="width:223px;">Biolegend</td>
			<td>321106</td>
			<td>Clone 15-2, PE conjugated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:301px;">Anti-CD163 (Human)</td>
			<td style="width:223px;">Biolegend</td>
			<td>333612</td>
			<td>Clone GHI/61, BV421 conjugated</td>
		</tr>
	</tbody>
</table>

isolation and in vitro culture of murine and human alveolar macrophages

Alveolar macrophages are terminally differentiated, lung-resident macrophages of prenatal origin. Alveolar macrophages are unique in their long life and their important role in lung development and function, as well as their lung-localized responses to infection and inflammation. To date, no unified method for identification, isolation, and handling of alveolar macrophages from humans and mice exists. Such a method is needed for studies on these important innate immune cells in various experimental settings. The method described here, which can be easily adopted by any laboratory, is a simplified approach to harvesting alveolar macrophages from bronchoalveolar lavage fluid or from lung tissue and maintaining them in vitro. Because alveolar macrophages primarily occur as adherent cells in the alveoli, the focus of this method is on dislodging them prior to harvest and identification. The lung is a highly vascularized organ, and various cell types of myeloid and lymphoid origin inhabit, interact, and are influenced by the lung microenvironment. By using the set of surface markers described here, researchers can easily and unambiguously distinguish alveolar macrophages from other leukocytes, and purify them for downstream applications. The culture method developed herein supports both human and mouse alveolar macrophages for in vitro growth, and is compatible with cellular and molecular studies.

The flow cytometric approach to identify mouse AMs is shown in Figure 1. This includes analysis of a minimum set of surface markers necessary in distinguishing AMs from other lung-resident or lung-infiltrating phagocytes. Differential analysis is required to positively identify AMs from interstitial macrophages, dendritic cells, neutrophils, monocytes, and monocyte-derived pulmonary macrophages that occur in lungs. The following scheme of surface markers can ...

Watch this Scientific Journal Video about Isolation and In Vitro Culture of Murine and Human Alveolar Macrophages at JoVE.com

Isolation and In Vitro Culture of Murine and Human Alveolar Macrophages

This communication describes methodologies for isolation and culture of alveolar macrophages from humans and murine models for experimental purposes.

Isolation and In Vitro Culture of Murine and Human Alveolar Macrophages

Alveolar macrophages are terminally differentiated, lung-resident macrophages of prenatal origin. Alveolar macrophages are unique in their long life and ...

The overall goal of this procedure is to isolate human and mice alveolar macrophages from lungs and bronchoalveolar lavage fluid and develop the method for their in vitro culture. This method can help answer some key questions in the field of pulmono immunology, such as the role of alveolar macrophages in respiratory infection, inflammation and autoimmunity. The main advantage of this technique is to be able to distinguish the alveolar macrophages from the other lung leukocytes and obtain a population of highly purified alveolar macrophages for experimental purposes.Place an anesthetized mouse on a dissection surface with the ventral side facing up. Apply ophthalmic vet ointment on the eyes to prevent dehydration. Wipe the entire ventral surface of the mouse with sterile alcohol prep pads, saturated with 70%isopropanol, to disinfect.Mount the mouse with all four legs retained. Gently open the abdominal cavity with micro dissection tools. Care must be taken to open as much area as possible without damaging any visceral organs or creating overhanging tissue.Gently open the thoracic cavity by slowly incising the rib cage through the mediastinum. Ideally, the rib cage can be excised from side to side. Extreme care must be taken not to injure the pleura of the lungs while opening the thoracic cavity.Locate the inferior vena cava and make an incision to bleed the mouse. Use absorbent cotton pads to soak up blood. Inject 10 milliliters of ice cold phosphate buffered saline into the right ventricle to flush circulating blood cells.Absorb the flow of blood with absorbent cotton pads. Once completely perfused, the lungs will appear blanched and are then ready for lavage. Gently cut open the skin and muscle in the neck to expose the airway.Carefully excise the adjoining muscles, cartilages, and fat tissues, without damaging the trachea. Next, make a small incision on the trachea, posterior to the larynx. This incision should be just enough to insert a catheter into while the trachea is still attached to the larynx.The single most critical step in collecting BAL fluid is to securely attach a catheter to the trachea that will minimize leaks during lavage. Insert a one inch 22 gauge catheter without a needle into the trachea towards the lungs. Secure the catheter with a silk braided suture and a square knot.Having sturdy hands and for following this step, slowly and gently prevents rupture of the trachea and lungs. Attach a one milliliter syringe, filled with ice cold BAL buffer to the catheter and slowly instill the buffer into the lungs. This will inflate the lungs.Keep the syringe attached to the catheter for five seconds, and then aspirate the lavage fluid by gently pulling the piston. This will deflate the lungs. Collect the fluid in a 15 milliliter conical tube, placed on ice.Repeat the inflation and deflation nine more times, and pool the lavage fluid. Do not exceed one milliliter of buffer per flush, as that may exceed the lung capacity and lead to its rupture. Centrifuge the 10 milliliters of BAL fluid at 250 times g and four degrees Celsius for 10 minutes.The cell pellet contains BAL cells. Resuspend the BAL cells in 100 microliters of flow sorting buffer. Proceed to stain and sort the cells as described in the text protocol.Prepare an anesthetized mouse for dissection, perform incisions and bleed the mouse as before. Inject 10 milliliters of ice cold PBS into the right ventricle to flush circulating blood cells. Once completely perfused, the lungs will appear blanched and are ready for harvest.Dissect out the lungs by severing the trachea, blood vessels and ligaments into a 15 milliliter conical tube, with five milliliters of cold DMEM. Maintain it on ice until the next step. Transfer the perfused lungs into a sterile and pyrogen-free 60 millimeter culture dish with three milliliters of DMEM.With the help of dissecting forceps, tease out the airways and other hard non-lung tissue material, if present. Mince the lung tissue with a scalpel to less than one millimeter size. Add 300 micrograms per milliliter of Liberase TL, and five units per milliliter of DNAse one.Mix by pipetting and incubate at 37 degrees Celsius in an incubator for 25 minutes. After 10 minutes, gently mix once by pipetting. Pass the dissociated lungs through a 100 micron cell strainer installed on a 50 milliliter conical tube.Use the back of a plunger from a one milliliter syringe to mash up cell clumps on the filter. Wash the filter with 20 milliliters of wash buffer. Centrifuge at 500 times g and four degrees Celsius for five minutes.Discard the supernatant, and resuspend the cell pellet in 20 milliliters of wash buffer. Repeat the straining and centrifugation steps twice, changing the filter and tube each time. Finally, prepare the single cell suspension by adding 100 microliters of flow sorting buffer to the cell pellet.Perform antibody staining and cell sorting, as described in the text protocol. Following the cell sorting, harvest the cells by centrifuging at 250 times g and four degrees Celsius for 10 minutes. Resuspend the mouse AMs in one milliliter of mouse AM culture medium.Based on the yield and experimental necessity, seed the cells in chamber slides, culture dishes, or culture flasks. Ideally, seed the AMs at 100, 000 per milliliter with 10 milliliters of medium in a T 25 tissue culture flask. Incubate the cells in a 37 degree Celsius humidified incubator with 5%carbon dioxide atmosphere.At 24 hours post-seeding, AMs should be adherent and will not be detached by a gentle change of culture medium. Remove the medium by aspiration from one end, and replenish with fresh medium pre-warmed to 37 degrees Celsius. Finally, observe the flask under an inverted microscope.Flow cytometric assessment of alveolar macrophages in mouse broncho alveolar lavage fluid is shown. The alveolar macrophages are positive identified for being CD45 positive, CD11c positive, and Siglec-F positive cells. Shown here, is a representative result of mouse alveolar macrophages cultured in vitro for 24 hours.The cells have become adherent and a gentle change of culture medium will not detach them. Once mastered, this technique can be done in approximately two hours, if it is performed properly. After watching this video, you should have a good understanding of how to distinguish the mouse and human alveolar macrophages from other lung cells.Also, as the procedures for obtaining a beautiful population of alveolar macrophages for downstream experiments. While attempting this procedure, it's important to remember that not all lung resident macrophages or phagocytes are alveolar macrophages. The alveolar macrophages are a type of specialized cells present in the lungs since birth.For isolation of alveolar macrophages, the focus should be on viable extraction methods from the alveolar micro environment. The in vitro culture method developed here supports growth of alveolar macrophages in a laboratory condition that can be utilized in molecular and cellular assays. Following this procedure, other methods like adoptive cell transfer, antigen presentation and evaluating response to inflammatory stimuli can be performed in order to answer additional questions on the biology of alveolar macrophages.

isolation-vitro-culture-murine-human-alveolar

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JoVE Journal

Immunology and Infection

22.9K vistas.  St. Joseph's Hospital and Medical Center. The overall goal of this procedure is to isolate human and mice alveolar macrophages from lungs and bronchoalveolar lavage fluid and develop the method for their in vitro culture. This method can help answer some key questions in the field of pulmono immunology, such as the role of alveolar macrophages in respiratory infection, inflammation and autoimmunity. The main advantage of this technique is to be able to distinguish the alveolar macrophages from the other lung leukocytes and obtain a p...