Name: isolation, characterization and functional examination of the gingival immune cell network
Uploaded: 2016-02-16T15:00:00
Description: Watch this Scientific Journal Video about Isolation, Characterization and Functional Examination of the Gingival Immune Cell Network at JoVE.com

Authors were funded in part by the intramural program of NIDCR (N.M.M) and supported by a Wellcome Trust Stepping Stones Fellowship (097820/Z/11/B to J.E.K) and by a Manchester Collaborative Centre for Inflammation Research grant (to J.E.K). The authors thank Teresa Wild for critically reviewing the manuscript.

All experimental procedures described in this protocol followed required guidelines and were approved by the Institutional Animal Care and Use Committee, NIDCR/NIH.
1. Prepare in Advance
<ol>
	<li>Prepare Complete media: RPMI supplemented with 2 mM L-glutamine, 100 units/ml penicillin, 100 ug/ml streptomycin and 10% FBS.</li>
	<li>Prepare DNase media: 50 ml of RPMI media supplemented with 7.5 &#181;g DNase (Make fresh, keep on ice at all times).</li>
	<li>Prepare Collagenase-DNase media: 5 ml of DNase media plus...

<ol>
	<li>Aas, J. A., Paster, B. J., Stokes, L. N., Olsen, I., Dewhirst, F. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defining+The+Normal+Bacterial+Flora+Of+The+Oral+Cavity.">Defining The Normal Bacterial Flora Of The Oral Cavity.</a> J Clin Microbiol. 43, 5721-5732 (2005).</li><li>Belkaid, Y., Naik, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Compartmentalized+And+Systemic+Control+Of+Tissue+Immunity+By+Commensals.">Compartmentalized And Systemic Control Of Tissue Immunity By Commensals.</a> Nat Immunol. 14, 646-653 (2013).</li><li>Darveau, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Periodontitis:+A+Polymicrobial+Disruption+Of+Host+Homeostasis.">Periodontitis: A Polymicrobial Disruption Of Host Homeostasis.</a> Nat Rev Microbiol. 8, 481-490 (2010).</li><li>Hajishengallis, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunomicrobial+Pathogenesis+Of+Periodontitis:+Keystones,+Pathobionts,+And+Host+Response.">Immunomicrobial Pathogenesis Of Periodontitis: Keystones, Pathobionts, And Host Response.</a> Trends Immunol. 35, 3-11 (2014).</li><li>Eke, P. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prevalence+Of+Periodontitis+In+Adults+In+The+United+States:+2009+And+2010.">Prevalence Of Periodontitis In Adults In The United States: 2009 And 2010.</a> J Dent Res. 91, 914-920 (2012).</li><li>Moutsopoulos, N. M., Lionakis, M. S., Hajishengallis, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inborn+Errors+In+Immunity:+Unique+Natural+Models+To+Dissect+Oral+Immunity.">Inborn Errors In Immunity: Unique Natural Models To Dissect Oral Immunity.</a> J Dent Res. , (2015).</li><li>Hajishengallis, G., Lamont, R. J., Graves, D. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Enduring+Importance+Of+Animal+Modelsin+Understanding+Periodontal+Disease.">The Enduring Importance Of Animal Modelsin Understanding Periodontal Disease.</a> Virulence. 6, 229-235 (2015).</li><li>Sharrow, S. O., Coligan, J. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+Of+Flow+Cytometry+Data.">Analysis Of Flow Cytometry Data.</a> Current Protocols In Immunology. , (2001).</li><li>Arizon, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Langerhans+Cells+Down-Regulate+Inflammation-Driven+Alveolar+Bone+Loss.">Langerhans Cells Down-Regulate Inflammation-Driven Alveolar Bone Loss.</a> Proc Natl Acad Sci U S A. 109, 7043-7048 (2012).</li><li>Moutsopoulos, N. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defective+Neutrophil+Recruitment+In+Leukocyte+Adhesion+Deficiency+Type+I+Disease+Causes+Local+IL-17-Driven+Inflammatory+Bone+Loss.">Defective Neutrophil Recruitment In Leukocyte Adhesion Deficiency Type I Disease Causes Local IL-17-Driven Inflammatory Bone Loss.</a> Sci Transl Med. 6, 229-240 (2014).</li><li>Gaffen, S. L., Jain, R., Garg, A. V., Cua, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+IL-23-IL-17+Immune+Axis:+From+Mechanisms+To+Therapeutic+Testing.">The IL-23-IL-17 Immune Axis: From Mechanisms To Therapeutic Testing.</a> Nat Rev Immunol. 14, 585-600 (2014).</li></ol>

The current technique successfully yields a large number of immune cells (from a single mouse) suitable, not only for phenotypic characterization, but also for functional studies ex vivo. Another group had previously published a protocol to isolate and characterize murine gingival immune cells and introduced the value of using multicolor flow cytometry in the study of periodontitis in animal models 9. Following considerable troubleshooting the key modification in this protocol was to include dissectio...

Gingival tissues surround the human and murine dentition and are constantly exposed to the complex biofilm of the tooth 1. The immune cell network policing the gingival barrier is vital to maintaining tissue integrity, ensuring homeostasis with the local commensal microbes and, at the same time, providing effective immunity against pathogenic challenge 2. To achieve homeostasis, the immune system is carefully tailored to the gingival environment creating a highly-specialized immune cell network, yet little detail is known of the gingival immune cell populations and their role in maintaining tissue immunity 2.
When immune homeostasis is disrupted at the gingiva, either through increased host susceptibility and/or presence of dysbiotic microbial communities, an inflammatory condition, periodontitis arises 34. Periodontitis is a common inflammatory disease, leading to loss of tooth supporting structures. In its severe forms it is seen in approximately 10% of the general population 5. Dissecting the key factors involved in periodontitis susceptibility and progression has proven difficult 6. However, animal models have been extremely useful in understanding the mechanisms of periodontitis initiation and progression 7. Models can be employed to define the key cell populations and molecular mediators that are vital for maintaining immune homeostasis and drive development of periodontitis. Such insight will transform our understanding of gingiva-specific control of immune homeostasis and further our current understanding of disease pathogenesis.

<table border="0" cellpadding="0" cellspacing="0" width="914">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Fine Scissors</td>
			<td style="width:188px;">Fine science tools</td>
			<td style="width:188px;">14058-11</td>
			<td style="width:235px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Scalpel Handle #3</td>
			<td style="width:188px;">Fine science tools</td>
			<td style="width:188px;">10003-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Scalpel Blades #10</td>
			<td style="width:188px;">Fine science tools</td>
			<td style="width:188px;">10010-00</td>
			<td>Sterile</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Splinter Forceps</td>
			<td style="width:188px;">Integra Miltex</td>
			<td style="width:188px;">6-304</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Needles with regular bevel&#160;</td>
			<td style="width:188px;">BD Medical</td>
			<td style="width:188px;">305109</td>
			<td>27G, 12.7 mm length</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Monoject syringes</td>
			<td style="width:188px;">Covidien</td>
			<td style="width:188px;">8881513934</td>
			<td>Luer-lock tip, 3mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">PBS, pH 7.4</td>
			<td style="width:188px;">Life Technologies</td>
			<td style="width:188px;">10010-049</td>
			<td>Without Calcium and Magnesium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">RPMI 1640</td>
			<td style="width:188px;">Lonza</td>
			<td style="width:188px;">12-167F</td>
			<td>Without L-glutamine</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">DNase I from bovine pancreas</td>
			<td style="width:188px;">Sigma-Aldrich</td>
			<td style="width:188px;">DN25-1G</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:304px;">Collagenase type IV</td>
			<td style="width:188px;">Gibco (by Life technologies)</td>
			<td style="width:188px;">17104-019</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Fetal Bovine Serum</td>
			<td style="width:188px;">Gemini Bio-products</td>
			<td style="width:188px;">100-106</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Gentamicin 50 mg/ml</td>
			<td style="width:188px;">Quality biological</td>
			<td style="width:188px;">120-098-661EA</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:304px;">Pen Strep</td>
			<td style="width:188px;">Gibco (by Life technologies)</td>
			<td style="width:188px;">15140-122</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:304px;">L-Glutamine</td>
			<td style="width:188px;">Gibco (by Life technologies)</td>
			<td style="width:188px;">25030-081</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">0.5M EDTA pH 8.0</td>
			<td style="width:188px;">Quality biological</td>
			<td style="width:188px;">351-027-721EA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">50 mL tubes</td>
			<td style="width:188px;">Corning</td>
			<td style="width:188px;">352070</td>
			<td>Polypropylene, sterile</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">70 &#956;M Cell Strainers</td>
			<td style="width:188px;">Corning</td>
			<td style="width:188px;">352350</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Petri dishes</td>
			<td style="width:188px;">Corning</td>
			<td style="width:188px;">351029</td>
			<td>Sterile</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">5 mL FACS tubes</td>
			<td style="width:188px;">Corning</td>
			<td style="width:188px;">352052</td>
			<td>Sterile</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">BD GolgiPlug</td>
			<td style="width:188px;">BD Biosciences</td>
			<td style="width:188px;">555029</td>
			<td>Contains brefeldin A solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Phorbol 12-Myristate 13-Acetate (PMA)</td>
			<td style="width:188px;">Sigma-Aldrich</td>
			<td style="width:188px;">P8139</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Ionomycin Calcium Salt</td>
			<td style="width:188px;">Sigma-Aldrich</td>
			<td style="width:188px;">13909</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Saponin from quillaja bark</td>
			<td style="width:188px;">Sigma-Aldrich</td>
			<td style="width:188px;">S4521</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">LIVE/DEAD Fixable Aqua Dead Cell Stain Kit</td>
			<td style="width:188px;">Life Technologies</td>
			<td>L34957</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Anti-Mouse CD45 Alexa Fluor 700</td>
			<td style="width:188px;">eBioscience</td>
			<td style="width:188px;">56-0451-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Anti-Mouse CD4 eFluor 450</td>
			<td style="width:188px;">eBioscience</td>
			<td style="width:188px;">48-0042-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Anti-Mouse TCR beta APC eFluor 780</td>
			<td style="width:188px;">eBioscience</td>
			<td style="width:188px;">47-5961-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Anti-Mouse gamma delta TCR FITC</td>
			<td style="width:188px;">eBioscience</td>
			<td style="width:188px;">11-5711-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Anti-Mouse IL-17A APC</td>
			<td style="width:188px;">eBioscience</td>
			<td style="width:188px;">12-7311-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Anti-Mouse IFN-&#947; PE</td>
			<td style="width:188px;">eBioscience</td>
			<td>11-5931-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Anti-Mouse NK1.1 PE-Cy7</td>
			<td style="width:188px;">eBioscience</td>
			<td style="width:188px;">25-5941-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Anti-Mouse CD90.2 APC eFluor 780</td>
			<td style="width:188px;">eBioscience</td>
			<td style="width:188px;">47-0902-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Anti-Mouse CD3e FITC</td>
			<td style="width:188px;">eBioscience</td>
			<td style="width:188px;">11-0031-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Anti-Mouse CD19 FITC</td>
			<td style="width:188px;">eBioscience</td>
			<td style="width:188px;">11-0193-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Anti-Mouse CD11b FITC</td>
			<td style="width:188px;">eBioscience</td>
			<td style="width:188px;">11-0112-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Anti-Mouse CD11c FITC</td>
			<td style="width:188px;">eBioscience</td>
			<td style="width:188px;">11-0114-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Anti-Mouse TCR beta FITC</td>
			<td style="width:188px;">eBioscience</td>
			<td style="width:188px;">11-5961-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Anti-Mouse Ly-6G FITC</td>
			<td style="width:188px;">eBioscience</td>
			<td style="width:188px;">11-5931-82</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Anti-Mouse Ly-6C FITC</td>
			<td style="width:188px;">BD Pharmingen</td>
			<td style="width:188px;">553104</td>
			<td></td>
		</tr>
	</tbody>
</table>

isolation, characterization and functional examination of the gingival immune cell network

Immune cell networks in tissues play a vital role in mediating local immunity and maintaining tissue homeostasis, yet little is known of the resident immune cell populations in the oral mucosa and gingiva. We have established a technique for the isolation and study of immune cells from murine gingival tissues, an area of constant microbial exposure and a vulnerable site to a common inflammatory disease, periodontitis. Our protocol allows for a detailed phenotypic characterization of the immune cell populations resident in the gingiva, even at steady state. Our procedure also yields sufficient cells with high viability for use in functional studies, such as the assessment of cytokine secretion ex vivo. This combination of phenotypic and functional characterization of the gingival immune cell network should aid towards investigating the mechanisms involved in oral immunity and periodontal homeostasis, but will also advance our understanding of the mechanisms involved in local immunopathology.

To illustrate application of the protocol, we show representative results examining the immune cell network in the gingiva of mice with and without periodontitis (WT vs. LFA-/-, Figure 2A-C). Representative FACS plots show live CD45+ hematopoietic cells in the gingiva (Figure 2A, 2C). Isolation and processing of immune cells with this protocol yields sufficient cells to perform ex vivo stimu...

Watch this Scientific Journal Video about Isolation, Characterization and Functional Examination of the Gingival Immune Cell Network at JoVE.com

Isolation, Characterization and Functional Examination of the Gingival Immune Cell Network

We have established a technique for the isolation, phenotypic characterization and functional analysis of immune cells from murine gingiva.

Immune cell networks in tissues play a vital role in mediating local immunity and maintaining tissue homeostasis, yet little is known of the resident ...

The overall goal of this method is to isolate gingival immune cells for the in-depth characterization of the immune responses related to oral immunity and periodontitis. This method can help answer key questions in the field of oral immunity, such as what cellular factors are implicated in the pathogenesis of periodontitis. The main advantages of this technique are that it allows the evaluation of the oral immune cell network and the isolation of enough viable cells for downstream in-vitro investigations.As a first step of this protocol, begin by placing pins to immobilize the body of the mouse and open the thoracic and abdominal cavities to expose the heart and internal organs. Next, make an incision in the vena cava, and use a 3-milliliter syringe, equipped with a 27-gauge needle, to profuse 3 milliliters of PBS via the left ventricle. When all of the blood has been flushed, pin the head of the mouse onto a dissecting pad, with the stomach facing up.Then use scissors to cut each commissure of the lip towards the neck, separating the skin that covers the mandible and neck region, and exposing the underlying tissues and muscles. Cut between the lower incisors to separate both sides of the mandible. Immobilize each side of the separated mandible with 25-gauge needles to access the oral cavity.After identifying the palate, use a number 10 surgical blade to make vertical incisions just anterior to the first molar, and posterior to the third molar. Then dissect the tissue away from the nasal cavity, and also dissect the blocks from the mandible. Then eliminate the excess tissue from the border of the gingiva and transfer the maxillary and mandibular blocks into a 50-milliliter conical tube containing 5 milliliters of collagenase and DNase on ice.Digest the tissue in a shaker incubator at 37 degrees Celsius for one hour, adding 50 microliters of 0.5 molar EDTA during the last five minutes. Then add 5 milliliters of cold DNase medium to the tissues, and gently mix the tube contents by swirling. Next, transfer the four blocks of tissue into a petri dish.And cover them with 500 microliters of fresh DNase medium. Use a scalpel to remove the gingiva from each block of tissue. And transfer the entire contents of the dish into a 70 micron cell strainer on top of a 50-milliliter tube.Wash the petri dish and strainer with 3 to 5 milliliters of fresh DNase medium. And then use the plunger of a sterile, 3-milliliter syringe to mash the gingival tissue against the mesh of the strainer. Rinse the strainer with 30 to 35 millilters of cold DNase medium, and centrifuge the filtrate.Then resuspend the palate in 1 milliliter of complete medium, and determine the number of viable cells. The isolation and processing of immune cells as just demonstrated, yields a sufficient number of cells to perfom an ex-vivo stimulation and characterization of the gingival cell cytokine secretion patterns from both wild-type, as well as periodontitis-susceptible animals. Indeed, the murine gingival immune cell composition can be analyzed as demonstrated in these density plots evaluating the t and natural killer cell compartments in periodontitis-susceptible LFA knockout mice.Using the appropriate gating strategies, the intracellular cytokine production of TCR beta CD4 positive, TCR beta CD8 positive, and TCR gamma delta positive t cells, as well as NK, and innate lymphoid cells, can also be determined. Once mastered, the cells can be isolated in three hours for immunostaining if the technique is performed properly. While attempting this procedure, it's important to remember to complete all of the steps efficiently and quickly, keeping the cells on ice whenever they are not being manipulated.Following this procedure, other methods, like cell sorting, can be performed to answer additional questions related to the function of the specific cell subsets.

isolation-characterization-functional-examination-gingival-immune

Research

JoVE Journal

Immunology and Infection

Measuring Calpain Activity in Fixed and Living Cells by Flow Cytometry

Calpains are ubiquitous intracellular, calcium-sensitive, neutral cysteine proteases 1. Calpains play crucial roles in many physiological processes, including signaling, cytoskeletal remodeling, regulation of gene expression, apoptosis and cell cycle progression 1. Calpains have been implicated in many pathologies including muscular dystrophies, cancer, diabetes, Alzheimer's disease and multiple sclerosis 1. Calpain regulation is complex and incompletely understood. mRNA and protein levels correlate poorly with activity, limiting the use of gene or protein expression techniques to measure calpain activity. This video protocol details a flow cytometric assay developed in our laboratory for measuring calpain activity in fixed and living cells. This method uses the fluorescent substrate BOC-LM-CMAC, which is cleaved specifically by calpain, to measure calpain activity. 2 In this video, calpain activity in fixed and living murine 32Dkit leukemia cells, alone or as part of a splenocyte population is measured using an LSRII (BD Bioscience). 32Dkit cells are shown to have elevated activity compared to normal splenocytes.

This article will detail the protocol for measuring calpain activity in fixed and living cells using flow cytometry.

Calpains are ubiquitous intracellular, calcium-sensitive, neutral cysteine proteases 1. Calpains play crucial roles in many physiological processes, ...

Isolation of Functional Cardiac Immune Cells

Cardiac immune cells are gaining interest for the roles they play in the pathological remodeling in many cardiac diseases.1-5 These immune cells, which include mast cells, T-cells and macrophages; store and release a variety of biologically active mediators including cytokines and proteases such as tryptase.6-8 These mediators have been shown to be key players in extracellular matrix metabolism by activating matrix metalloproteinases or causing collagen accumulation by modulating the cardiac fibroblasts' function.9-11 However, available techniques for isolating cardiac immune cells have been problematic because they use bacterial collagenase to digest the myocardial tissue. This technique causes activation of the immune cells and thus a loss of function. For example, cardiac mast cells become significantly less responsive to compounds that cause degranulation.12 Therefore, we developed a technique that allows for the isolation of functional cardiac immune cells which would lead to a better understanding of the role of these cells in cardiac disease.13, 14
This method requires a familiarity with the anatomical location of the rat's xiphoid process, axilla and falciform ligament, and pericardium of the heart. These landmarks are important to increase success of the procedure and to ensure a higher yield of cardiac immune cells. These isolated cardiac immune cells can then be used for characterization of functionality, phenotype, maturity, and co-culture experiments with other cardiac cells to gain a better understanding of their interactions.

This method for isolating functional immune cells from the heart provides an alternative to the conventional methods of collagenase digestion, which causes unwanted immune cell activation, resulting in a decreased responsiveness of these cells. Our method of isolation yields functional cardiac immune cells by avoiding problems associated with enzymatic digestion.

Cardiac immune cells are gaining interest for the roles they play in the pathological remodeling in many cardiac diseases.1-5  These immune cells, which ...

Differentiating Functional Roles of Gene Expression from Immune and Non-immune Cells in Mouse Colitis by Bone Marrow Transplantation

To understand the role of a gene in the development of colitis, we compared the responses of wild-type mice and gene-of-interest deficient knockout mice to colitis. If the gene-of-interest is expressed in both bone marrow derived cells and non-bone marrow derived cells of the host; however, it is possible to differentiate the role of a gene of interest in bone marrow derived cells and non- bone marrow derived cells by bone marrow transplantation technique. To change the bone marrow derived cell genotype of mice, the original bone marrow of recipient mice were destroyed by irradiation and then replaced by new donor bone marrow of different genotype. When wild-type mice donor bone marrow was transplanted to knockout mice, we could generate knockout mice with wild-type gene expression in bone marrow derived cells. Alternatively, when knockout mice donor bone marrow was transplanted to wild-type recipient mice, wild-type mice without gene-of-interest expressing from bone marrow derived cells were produced. However, bone marrow transplantation may not be 100% complete. Therefore, we utilized cluster of differentiation (CD) molecules (CD45.1 and CD45.2) as markers of donor and recipient cells to track the proportion of donor bone marrow derived cells in recipient mice and success of bone marrow transplantation. Wild-type mice with CD45.1 genotype and knockout mice with CD45.2 genotype were used. After irradiation of recipient mice, the donor bone marrow cells of different genotypes were infused into the recipient mice. When the new bone marrow regenerated to take over its immunity, the mice were challenged by chemical agent (dextran sodium sulfate, DSS 5%) to induce colitis. Here we also showed the method to induce colitis in mice and evaluate the role of the gene of interest expressed from bone-marrow derived cells. If the gene-of-interest from the bone derived cells plays an important role in the development of the disease (such as colitis), the phenotype of the recipient mice with bone marrow transplantation can be significantly altered. At the end of colitis experiments, the bone marrow derived cells in blood and bone marrow were labeled with antibodies against CD45.1 and CD45.2 and their quantitative ratio of existence could be used to evaluate the success of bone marrow transplantation by flow cytometry. Successful bone marrow transplantation should show a vast majority of donor genotype (in term of CD molecule marker) over recipient genotype in both the bone marrow and blood of recipient mice.

Bone marrow transplantation provides a way to change the genotype of the bone marrow derived cells. If the gene of interest is expressed in both bone marrow derived cells and non-bone marrow derived cells, bone marrow transplantation can change the bone marrow derived cells to a different genotype without changing the non-bone marrow derived cell genotype.

To understand the role of a gene in the development of colitis, we compared the responses of wild-type mice and gene-of-interest deficient knockout mice ...

Flow Cytometric Isolation of Primary Murine Type II Alveolar Epithelial Cells for Functional and Molecular Studies

Throughout the last years, the contribution of alveolar type II epithelial cells (AECII) to various aspects of immune regulation in the lung has been increasingly recognized. AECII have been shown to participate in cytokine production in inflamed airways and to even act as antigen-presenting cells in both infection and T-cell mediated autoimmunity 1-8. Therefore, they are especially interesting also in clinical contexts such as airway hyper-reactivity to foreign and self-antigens as well as infections that directly or indirectly target AECII. However, our understanding of the detailed immunologic functions served by alveolar type II epithelial cells in the healthy lung as well as in inflammation remains fragmentary. Many studies regarding AECII function are performed using mouse or human alveolar epithelial cell lines 9-12. Working with cell lines certainly offers a range of benefits, such as the availability of large numbers of cells for extensive analyses. However, we believe the use of primary murine AECII allows a better understanding of the role of this cell type in complex processes like infection or autoimmune inflammation. Primary murine AECII can be isolated directly from animals suffering from such respiratory conditions, meaning they have been subject to all additional extrinsic factors playing a role in the analyzed setting. As an example, viable AECII can be isolated from mice intranasally infected with influenza A virus, which primarily targets these cells for replication 13. Importantly, through ex vivo infection of AECII isolated from healthy mice, studies of the cellular responses mounted upon infection can be further extended.
Our protocol for the isolation of primary murine AECII is based on enzymatic digestion of the mouse lung followed by labeling of the resulting cell suspension with antibodies specific for CD11c, CD11b, F4/80, CD19, CD45 and CD16/CD32. Granular AECII are then identified as the unlabeled and sideward scatter high (SSChigh) cell population and are separated by fluorescence activated cell sorting 3.
In comparison to alternative methods of isolating primary epithelial cells from mouse lungs, our protocol for flow cytometric isolation of AECII by negative selection yields untouched, highly viable and pure AECII in relatively short time. Additionally, and in contrast to conventional methods of isolation by panning and depletion of lymphocytes via binding of antibody-coupled magnetic beads 14, 15, flow cytometric cell-sorting allows discrimination by means of cell size and granularity. Given that instrumentation for flow cytometric cell sorting is available, the described procedure can be applied at relatively low costs. Next to standard antibodies and enzymes for lung disintegration, no additional reagents such as magnetic beads are required. The isolated cells are suitable for a wide range of functional and molecular studies, which include in vitro culture and T-cell stimulation assays as well as transcriptome, proteome or secretome analyses 3, 4.

We describe the rapid isolation of primary murine type II alveolar epithelial cells (AECII) by flow cytometric negative selection. These AECII show high viability and purity and are suitable for a wide range of functional and molecular studies regarding their role in respiratory conditions such as autoimmune or infectious diseases.

Throughout  the last years, the contribution of alveolar type II epithelial cells (AECII)  to various aspects of immune regulation in the lung has been ...

Isolation, Processing and Analysis of Murine Gingival Cells

We have developed a technique to precisely isolate and process murine gingival tissue for flow cytometry and molecular studies. The gingiva is a unique and important tissue to study immune mechanisms because it is involved in host immune response against oral biofilm that might cause periodontal diseases. Furthermore, the close proximity of the gingiva to alveolar bone tissue enables also studying bone remodeling under inflammatory conditions. Our method yields large amount of immune cells that allows analysis of even rare cell populations such as Langerhans cells and T regulatory cells as we demonstrated previously 1. Employing mice to study local immune responses involved in alveolar bone loss during periodontal diseases is advantageous because of the availability of various immunological and experimental tools. Nevertheless, due to their small size and the relatively inconvenient access to the murine gingiva, many studies avoided examination of this critical tissue. The method described in this work could facilitate gingival analysis, which hopefully will increase our understating on the oral immune system and its role during periodontal diseases.

This study describes an efficient technique to isolate and process gingival tissues from the mouse oral cavity in order to produce a single-cell culture. The resulting cells can be further used for flow cytometry analysis and molecular studies.

We have developed a technique to precisely isolate and process murine gingival tissue for flow cytometry and molecular studies. The gingiva is a unique ...

An In Vitro Model for Measuring Immune Responses to Malaria in the Context of HIV Co-infection

Malaria and HIV co-infection is a growing health priority. However, most research on malaria or HIV currently focuses on each infection individually. Although understanding the disease dynamics for each of these pathogens independently is vital, it is also important that the interactions between these pathogens are investigated and understood. 
We have developed a versatile in vitro model of HIV-malaria co-infection to study host immune responses to malaria in the context of HIV infection. Our model allows the study of secreted factors in cellular supernatants, cell surface and intracellular protein markers, as well as RNA expression levels. The experimental design and methods used limit variability and promote data reliability and reproducibility. 
All pathogens used in this model are natural human pathogens (Plasmodium falciparum and HIV-1), and all infected cells are naturally infected and used fresh. We use human erythrocytes parasitized with P. falciparum and maintained in continuous in vitro culture. We obtain freshly isolated peripheral blood mononuclear cells from chronically HIV-infected volunteers. Every condition used has an appropriate control (P. falciparum parasitized vs. normal erythrocytes), and every HIV-infected donor has an HIV uninfected control, from which cells are harvested on the same day. This model provides a realistic environment to study the interactions between malaria parasites and human immune cells in the context of HIV infection.

An In Vitro Model for Measuring Immune Responses to Malaria in the Context of HIV Co-infection

Human co-infection is difficult to replicate in vitro. However, human malaria parasites can readily be cultured in vitro, as can freshly isolated human peripheral blood mononuclear cells naturally infected with HIV. This provides an excellent model for studying early immune responses to malaria parasites in the context of HIV co-infection.

Malaria and HIV co-infection is a growing health priority. However, most research on malaria or HIV currently focuses on each infection individually. ...

Isolation and Flow Cytometric Analysis of Immune Cells from the Ischemic Mouse Brain

Ischemic stroke initiates a robust inflammatory response that starts in the intravascular compartment and involves rapid activation of brain resident cells. A key mechanism of this inflammatory response is the migration of circulating immune cells to the ischemic brain facilitated by chemokine release and increased endothelial adhesion molecule expression. Brain-invading leukocytes are well-known contributing to early-stage secondary ischemic injury, but their significance for the termination of inflammation and later brain repair has only recently been noticed.
Here, a simple protocol for the efficient isolation of immune cells from the ischemic mouse brain is provided. After transcardial perfusion, brain hemispheres are dissected and mechanically dissociated. Enzymatic digestion with Liberase&#160;is followed by density gradient (such as Percoll) centrifugation to remove myelin and cell debris. One major advantage of this protocol is the single-layer density gradient procedure which does not require time-consuming preparation of gradients and can be reliably performed. The approach yields highly reproducible cell counts per brain hemisphere and allows for measuring several flow cytometry panels in one biological replicate. Phenotypic characterization and quantification of brain-invading leukocytes after experimental stroke may contribute to a better understanding of their multifaceted roles in ischemic injury and repair.

Inflammation plays a central role in the pathogenesis of ischemic stroke. Increasing evidence suggests that it acts as a double-edged sword which exacerbates early brain injury, but also contributes to later repair. This protocol describes the isolation of immune cells from the ischemic brain and their subsequent flow cytometric phenotyping.

Ischemic stroke initiates a robust inflammatory response that starts in the intravascular compartment and involves rapid activation of brain resident ...

Isolation and Characterization of Neutrophil-derived Microparticles for Functional Studies

Polymorphonuclear neutrophil-derived microparticles (PMN)-MPs) are lipid bilayer, spherical microvesicles with sizes ranging from 50&#8211;1,000 nm in diameter. MPs are a newly evolving, important part of cell-to-cell communication and signaling machinery. Because of their size and the nature of their release, until recently MP existence was overlooked. However, with improved technology and analytical methods their function in health and disease is now emerging. The protocols presented here are aimed at isolating and characterizing PMN-MPs by flow cytometry and immunoblotting. Moreover, several implementation examples are given. These protocols for MP isolation are fast, low-cost, and do not require the use of expensive kits. Furthermore, they allow for the labeling of MPs following isolation, as well as pre-labeling of source cells prior to MP release, using a membrane-specific fluorescent dye for visualization and analysis by flow cytometry. These methods, however, have several limitations including purity of PMNs and MPs and the need for sophisticated analytical instrumentation. A high-end flow cytometer is needed to reliably analyze MPs and minimize false positive reads due to noise or auto-fluorescence. The described protocols can be used to isolate and define MP biogenesis, and characterize their markers and variation in composition under different stimulating conditions. Size heterogeneity can be exploited to investigate whether the content of membrane particles versus exosomes is different, and whether they fulfill different roles in tissue homeostasis. Finally, following isolation and characterization of MPs, their function in cellular responses and various disease models (including, PMN-associated inflammatory disorders, such as Inflammatory Bowel Diseases or Acute Lung Injury) can be explored.

New protocols are described here to isolate and characterize microparticles derived from human and mouse neutrophils. These protocols utilize ultracentrifugation, flow cytometry, and immunoblotting techniques to analyze microparticle content, and they can be used to study the role of microparticles derived from various cell types in cellular function.

Polymorphonuclear neutrophil-derived microparticles (PMN)-MPs) are lipid bilayer, spherical microvesicles with sizes ranging from 50&#8211;1,000 nm in ...

Isolation of Peritoneum-derived Mast Cells and Their Functional Characterization with Ca2+-imaging and Degranulation Assays

Mast cells (MCs), as a part of the immune system, play a key role in defending the host against several pathogens and in the initiation of the allergic immune response. The activation of MCs via the cross-linking of surface IgE bound to high affinity IgE receptor (Fc&#949;RI), as well as through the stimulation of several other receptors, initiates the rise of the free intracellular Ca2+ level ([Ca2+]i) that promotes the release of inflammatory and allergic mediators. The identification of molecular constituents involved in these signaling pathways is crucial for understanding the regulation of MC function. In this article, we describe a protocol for the isolation of murine connective tissue type MCs by peritoneal lavage and cultivation of peritoneal MCs (PMCs). Cultures of MCs from various knockout mouse models by this methodology represent a useful approach to the identification of proteins involved in MC signaling pathways. In addition, we also describe a protocol for single cell Fura-2 imaging as an important technique for the quantification of Ca2+ signaling in MCs. Fluorescence-based monitoring of [Ca2+]i is a reliable and commonly used approach to study Ca2+ signaling events, including store-operated calcium entry, which is of utmost importance for MC activation. For the analysis of MC degranulation, we describe a &#946;-hexosaminidase release assay. The amount of &#946;-hexosaminidase released into the culture medium is considered as a degranulation marker for all three different secretory subsets described in MCs. &#946;-hexosaminidase can easily be quantified by its reaction with a colorigenic substrate in a microtiter plate colorimetric assay. This highly reproducible technique is cost-effective and requires no specialized equipment. Overall, the provided protocol demonstrates a high yield of MCs expressing typical MC surface markers, displaying typical morphological and phenotypic features of MCs, and demonstrating highly reproducible responses to secretagogues in Ca2+-imaging and degranulation assays.

Isolation of Peritoneum-derived Mast Cells and Their Functional Characterization with Ca2+-imaging and Degranulation Assays

Here, we present a protocol to isolate and cultivate murine peritoneal mast cells. We also describe two protocols for their functional characterization: a fluorescent imaging of intracellular free Ca2+ concentration and a degranulation assay based on colorimetric quantification of the released &#946;-hexosaminidase.

Mast cells (MCs), as a part of the immune system, play a key role in defending the host against several pathogens and in the initiation of the allergic ...

Isolation and Identification of Extravascular Immune Cells of the Heart

The immune system is an essential component of a healthy heart. The myocardium is home to a rich population of different immune cell subsets with functional compartmentalization both during steady state and during different forms of inflammation. Until recently, the study of immune cells in the heart required the use of microscopy or poorly developed digestion protocols, which provided enough sensitivity during severe inflammation but were unable to confidently identify small &#8212; but key &#8212; populations of cells during steady state. Here, we discuss a simple method combining enzymatic (collagenase, hyaluronidase and DNAse) and mechanical digestion of murine hearts preceded by intravascular administration of fluorescently-labelled antibodies to differentiate small but unavoidable intravascular cell contaminants. This method generates a suspension of isolated viable cells that can be analyzed by flow cytometry for identification, phenotyping and quantification, or further purified with fluorescence-activated cell sorting or magnetic bead separation for transcriptional analysis or in vitro studies. We include an example of a step-by-step flow cytometric analysis to differentiate the key macrophage and dendritic cell populations of the heart. For a medium sized experiment (10 hearts) the completion of the procedure requires 2&#8211;3 h.

This protocol presents a simple and efficient method to isolate, identify and quantify immune cells residing in the myocardium of mice during steady state or inflammation. The protocol combines enzymatic and mechanical digestion for the generation of a single cell suspension that can be further analyzed by flow cytometry.