Umbilical cords were collected with the assistance of the Birmingham Women's Health Care NHS Trust. HMM was supported by an Arthritis Research UK Career Development Fellowship (19899) and Systems Science for Health, University of Birmingham (5212).

1. Isolation and Culture of Primary Human Endothelial Cells and Mesenchymal Stem Cells
<ol>
	<li>Isolation and culture of human umbilical vein endothelial cells (HUVEC):
	<ol>
		<li>Put umbilical cord on a tray with paper towels and spray with 70% ethanol. Place in a tissue culture hood. Identify the vein and cannulate at both ends. Place a cable tie around the cannulated end to secure it.</li>
		<li>Wash out venous blood with PBS using a syringe. Fill syringe with air and pass through the vein to remove and discard th...

<ol>
	<li>Springer, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Traffic+signals+on+endothelium+for+lymphocyte+recirculation+and+leukocyte+emigration.">Traffic signals on endothelium for lymphocyte recirculation and leukocyte emigration.</a> Ann. Rev. Physiol. 57, 827-872 (1995).</li><li>Ley, K., Laudanna, C., Cybulsky, M. I., Nourshargh, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Getting+to+the+site+of+inflammation:+the+leukocyte+adhesion+cascade+updated.">Getting to the site of inflammation: the leukocyte adhesion cascade updated.</a> Nature reviews. Immunology. 7 (9), 678-689 (2007).</li><li>McGettrick, H. M., Butler, L. M., Buckley, C. D., Rainger, G. E., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+stroma+as+a+regulator+of+leukocyte+recruitment+in+inflammation.">Tissue stroma as a regulator of leukocyte recruitment in inflammation.</a> Journal of leukocyte biology. 91 (3), 385-400 (2012).</li><li>Serhan, C. N., Savill, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Resolution+of+inflammation:+the+beginning+programs+the+end.">Resolution of inflammation: the beginning programs the end.</a> Nature immunology. 6 (12), 1191-1197 (2005).</li><li>Schmidt, S., Moser, M., Sperandio, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+molecular+basis+of+leukocyte+recruitment+and+its+deficiencies.">The molecular basis of leukocyte recruitment and its deficiencies.</a> Molecular immunology. 55, 49-58 (2013).</li><li>Luu, N. T., Rainger, G. E., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+Ability+of+Exogenous+Chemotactic+Agents+to+Disrupt+Transendothelial+Migration+of+Flowing+Neutrophils.">Differential Ability of Exogenous Chemotactic Agents to Disrupt Transendothelial Migration of Flowing Neutrophils.</a> The Journal of Immunology. 164 (11), 5961-5969 (2000).</li><li>Smith, C. W., Rothlein, R., 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=Recognition+of+an+endothelial+determinant+for+CD+18-dependent+human+neutrophil+adherence+and+transendothelial+migration.">Recognition of an endothelial determinant for CD 18-dependent human neutrophil adherence and transendothelial migration.</a> The Journal of clinical investigation. 82 (5), 1745-1756 (1988).</li><li>Luscinskas, F. W., Brock, A. F., Arnaout, M. A., Gimbrone, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial-leukocyte+adhesion+molecule-1-dependent+and+leukocyte+(CD11/CD18)-dependent+mechanisms+contribute+to+polymorphonuclear+leukocyte+adhesion+to+cytokine-activated+human+vascular+endothelium.">Endothelial-leukocyte adhesion molecule-1-dependent and leukocyte (CD11/CD18)-dependent mechanisms contribute to polymorphonuclear leukocyte adhesion to cytokine-activated human vascular endothelium.</a> J. Immunol. 142 (7), (1989).</li><li>Bahra, P., Rainger, G. E., Wautier, J. L., Nguyet-Thin, L., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Each+step+during+transendothelial+migration+of+flowing+neutrophils+is+regulated+by+the+stimulatory+concentration+of+tumour+necrosis+factor-alpha.">Each step during transendothelial migration of flowing neutrophils is regulated by the stimulatory concentration of tumour necrosis factor-alpha.</a> Cell adhesion and communication. 6 (6), 491-501 (1998).</li><li>Piali, L., Weber, C., 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=The+chemokine+receptor+CXCR3+mediates+rapid+and+shear-resistant+adhesion-induction+of+effector+T+lymphocytes+by+the+chemokines+IP10+and+Mig.">The chemokine receptor CXCR3 mediates rapid and shear-resistant adhesion-induction of effector T lymphocytes by the chemokines IP10 and Mig.</a> European journal of immunology. 28 (3), 961-972 (1998).</li><li>McGettrick, H. M., Smith, 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=Fibroblasts+from+different+sites+may+promote+or+inhibit+recruitment+of+flowing+lymphocytes+by+endothelial+cells.">Fibroblasts from different sites may promote or inhibit recruitment of flowing lymphocytes by endothelial cells.</a> European journal of immunology. 39 (1), 113-125 (2009).</li><li>McGettrick, H. M., Hunter, K., Moss, P. a., Buckley, C. D., Rainger, G. E., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+observations+of+the+kinetics+of+migrating+T+cells+suggest+active+retention+by+endothelial+cells+with+continual+bidirectional+migration.">Direct observations of the kinetics of migrating T cells suggest active retention by endothelial cells with continual bidirectional migration.</a> Journal of leukocyte biology. 85 (1), 98-107 (2009).</li><li>McGettrick, H. M., Buckley, C. D., Filer, A., Rainger, G. E., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stromal+cells+differentially+regulate+neutrophil+and+lymphocyte+recruitment+through+the+endothelium.">Stromal cells differentially regulate neutrophil and lymphocyte recruitment through the endothelium.</a> Immunology. 131 (3), 357-370 (2010).</li><li>Tull, S. P., Yates, C. 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=Omega-3+Fatty+acids+and+inflammation:+novel+interactions+reveal+a+new+step+in+neutrophil+recruitment.">Omega-3 Fatty acids and inflammation: novel interactions reveal a new step in neutrophil recruitment.</a> PLoS biology. 7 (8), e1000177 (2009).</li><li>Ahmed, S. R., McGettrick, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prostaglandin+D2+regulates+CD4++memory+T+cell+trafficking+across+blood+vascular+endothelium+and+primes+these+cells+for+clearance+across+lymphatic+endothelium.">Prostaglandin D2 regulates CD4+ memory T cell trafficking across blood vascular endothelium and primes these cells for clearance across lymphatic endothelium.</a> Journal of immunology. 187 (3), 1432-1439 (2011).</li><li>Bradfield, P. F., Amft, N., 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=Rheumatoid+fibroblast-like+synoviocytes+overexpress+the+chemokine+stromal+cell-derived+factor+1+(CXCL12),+which+supports+distinct+patterns+and+rates+of+CD4++and+CD8++T+cell+migration+within+synovial+tissue.">Rheumatoid fibroblast-like synoviocytes overexpress the chemokine stromal cell-derived factor 1 (CXCL12), which supports distinct patterns and rates of CD4+ and CD8+ T cell migration within synovial tissue.</a> Arthritis and rheumatism. 48 (9), 2472-2482 (2003).</li><li>Filer, A., Parsonage, G., 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=Differential+survival+of+leukocyte+subsets+mediated+by+synovial,+bone+marrow,+and+skin+fibroblasts:+site-specific+versus+activation-dependent+survival+of+T+cells+and+neutrophils.">Differential survival of leukocyte subsets mediated by synovial, bone marrow, and skin fibroblasts: site-specific versus activation-dependent survival of T cells and neutrophils.</a> Arthritis and rheumatism. 54 (7), 2096-2108 (2006).</li><li>Lally, F., Smith, 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=A+novel+mechanism+of+neutrophil+recruitment+in+a+coculture+model+of+the+rheumatoid+synovium.">A novel mechanism of neutrophil recruitment in a coculture model of the rheumatoid synovium.</a> Arthritis and rheumatism. 52 (11), 3460-3490 (2005).</li><li>Chakravorty, S. J., McGettrick, H. M., Butler, L. M., Buckley, C. D., Rainger, G. E., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+in+vitro.+model+for+analysing+neutrophil+migration+into+and+away+from+the+sub-endothelial+space:+Roles+of+flow+and+CD31.">An in vitro. model for analysing neutrophil migration into and away from the sub-endothelial space: Roles of flow and CD31.</a> Biorheology. 43 (1), 71-82 (2006).</li><li>Rainger, G. E., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+Pathology+of+Atherosclerosis+Smooth+Muscle+Cells+Prime+Cocultured+Endothelial+Cells+for+Enhanced+Leukocyte+Adhesion.">Cellular Pathology of Atherosclerosis Smooth Muscle Cells Prime Cocultured Endothelial Cells for Enhanced Leukocyte Adhesion.</a> Circulation Research. 88 (6), 615-622 (2001).</li><li>Kuravi, S. J., McGettrick, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Podocytes+regulate+neutrophil+recruitment+by+glomerular+endothelial+cells+via+IL-6-mediated+crosstalk.">Podocytes regulate neutrophil recruitment by glomerular endothelial cells via IL-6-mediated crosstalk.</a> Journal of immunology. 193 (1), 234-243 (2004).</li><li>Parsonage, G., Filer, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+stromal+address+code+defined+by+fibroblasts.">A stromal address code defined by fibroblasts.</a> Trends in immunology. 26 (3), 150-156 (2005).</li><li>Luu, N. T., McGettrick, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crosstalk+between+mesenchymal+stem+cells+and+endothelial+cells+leads+to+downregulation+of+cytokine-induced+leukocyte+recruitment.">Crosstalk between mesenchymal stem cells and endothelial cells leads to downregulation of cytokine-induced leukocyte recruitment.</a> Stem cells. 31 (12), 2690-2702 (2013).</li><li>Bevilacqua, M. P., Nelson, R. M., Mannori, G., Cecconi, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial-leukocyte+adhesion+molecules+in+human+disease.">Endothelial-leukocyte adhesion molecules in human disease.</a> Annual review of medicine. 45, 361-378 (1994).</li><li>Stanness, K. A., Beatty, P. G., Ochs, H. D., Harlan, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+endothelial+cell+surface+factor(s)+induced+in+vitro.">An endothelial cell surface factor(s) induced in vitro.</a> 136 (12), 4548-4553 (1986).</li><li>Burton, V. J., Butler, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Delay+of+migrating+leukocytes+by+the+basement+membrane+deposited+by+endothelial+cells+in+long-term+culture.">Delay of migrating leukocytes by the basement membrane deposited by endothelial cells in long-term culture.</a> Experimental cell research. 317 (3), 276-292 (2011).</li><li>Luu, N. T., Rainger, G. E., Buckley, C. D., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CD31+Regulates+Direction+and+Rate+of+Neutrophil+Migration+over+and+under+Endothelial+Cells.">CD31 Regulates Direction and Rate of Neutrophil Migration over and under Endothelial Cells.</a> Journal of Vascular Research. 40 (5), 467-479 (2003).</li><li>McGettrick, H. M., Buckley, C. D., Ed Rainger, G., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+stromal+cells+on+lymphocyte+adhesion+and+migration+on+endothelial+cells.">Influence of stromal cells on lymphocyte adhesion and migration on endothelial cells.</a> Methods in molecular biology. 616, 49-68 (2010).</li><li>Butler, L. M., McGettrick, H. M., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Static+and+dynamic+assays+of+cell+adhesion+relevant+to+the+vasculature.">Static and dynamic assays of cell adhesion relevant to the vasculature.</a> Methods in molecular biology. 467, 211-228 (2009).</li><li>Jeffery, H. C., Buckley, C. D., Moss, P., Rainger, G. E., Nash, G. B., McGettrick, H. M. <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+the+effects+of+stromal+cells+on+the+migration+of+lymphocytes+into+and+through+inflamed+tissue+using+3-D+culture+models.">Analysis of the effects of stromal cells on the migration of lymphocytes into and through inflamed tissue using 3-D culture models.</a> Journal of immunological methods. 400-401, 45-57 (2013).</li></ol>

Here we describe two in vitro &#8220;vascular&#8221; models for studying the recruitment of circulating neutrophils by inflamed endothelium. A major advantage of these models is the ability to analyze each step in the leukocyte adhesion cascade in order, as would occur in vivo. We have previously observed a dose-dependent increase in neutrophil adhesion to and transmigration through TNF&#945;-stimulated EC9,29. We also describe how both models can be adapted to study the effects of stromal ce...

Inflammation is a protective response to microbial infection or tissue injury that requires tight regulation of leukocyte entry into and exit from the inflamed tissue to allow resolution1,2. Cross-talk between endothelial cells (EC) that line blood vessels, circulating leukocytes and tissue-resident stromal cells is essential for coordinating this process3. However, uncontrolled recruitment of leukocytes and their ineffective clearance underpin the development of chronic inflammatory diseases4. Our current understanding of leukocyte recruitment in health and disease is incomplete and more robust models are needed to analyze this process.
The mechanisms supporting the recruitment of leukocytes from blood through vascular EC in post-capillary venules have been well described1,2,5. Circulating leukocytes are captured by specialized receptors (e.g., VCAM-1, E-selectin, P-selectin) which are up-regulated on inflamed endothelium. These transient interactions allow leukocytes to interact with surface bound chemokines and lipid-derived mediators (either endothelial or stromal in origin) that activate integrins expressed by leukocytes6-11. This in turn stabilizes adhesion and drives migration across the endothelium and into the tissue12-15. Within tissue, recruited leukocytes are subjected to stromal-derived agents that influence their motility, function and survival16,17. Growing evidence strongly suggests that signals received at each stage of the recruitment process conditions leukocytes for the next. However, our understanding of leukocyte recruitment remains incomplete and very little is known about the components shaping leukocyte movement within tissue.
In Birmingham we have developed several in vitro &#8220;vascular&#8221; models to study the recruitment of leukocytes from flow9,18,19. We now understand that vascular EC act as immediate regulators of leukocyte recruitment responding to changes in their local microenvironment. Specifically, tissue-resident stromal cells can actively regulate the inflammatory response, in part by conversing with neighboring vascular EC to influence their role in recruitment3. We have previously shown that various stromal cells modulate the ability of EC to support adhesion and migration of leukocytes in a tissue-specific manner, and that these effects become altered in chronic diseases13,16,20,21. Thus, stromal cells establish tissue &#8216;address-codes&#8217; that define the context of each inflammatory response22. More recently, we have demonstrated that bone-marrow derived MSC (BMMSC) potently down-regulate the response of EC to cytokines, leading to a reduction in the recruitment of both neutrophils and lymphocytes23.
The mechanisms governing recruitment elucidated in vitro have largely used assays incorporating a single cell type (e.g., EC) or protein in isolation. However, these studies do not take into consideration the effects of the local tissue environment (i.e., the presence of stromal cells) on recruitment of leukocytes and their subsequent migration into the tissue. Here we describe two flow-based methods in which stromal cells, specifically mesenchymal stem cells (MSC), are co-cultured with EC23. Such models allow us to examine the effect of stromal cell on endothelial responses, in particular their ability to support leukocyte recruitment from flow.

<table border="0" cellpadding="0" cellspacing="0" >
	<tbody>
		<tr >
			<td >Collagenase Type Ia</td>
			<td >Sigma</td>
			<td>C2674</td>
			<td>Dilute in 10ml PBS to get a final concentration of 10mg/ml. Store at -20&#176;C in 1ml aliquots.</td>
		</tr>
		<tr >
			<td >Dulbecco&#39;s PBS</td>
			<td >Sigma</td>
			<td >D8662</td>
			<td>With calcium and magnesium chloride. Keep sterile and store at room temperature.</td>
		</tr>
		<tr >
			<td >1X Medium M199</td>
			<td >Gibco</td>
			<td >31150-022</td>
			<td>Warm in 37 &#176;C water bath before use.</td>
		</tr>
		<tr >
			<td >Gentamicin sulphate</td>
			<td >Sigma</td>
			<td >G1397</td>
			<td>Store at 4&#176;C. Add to M199 500ml bottle.</td>
		</tr>
		<tr >
			<td >Human epidermal growth factor</td>
			<td >Sigma</td>
			<td >E9644</td>
			<td>Store at -20&#176;C in 10&#181;l aliquots.</td>
		</tr>
		<tr >
			<td >Fetal calf serum (FCS)</td>
			<td >Sigma</td>
			<td >F9665</td>
			<td >FCS must be batch tested to ensure the growth and viability of isolated EC. Heat inactivate at 56&#176;C. Store in 10ml aliquots at -20&#176;C.</td>
		</tr>
		<tr >
			<td >Amphotericin B</td>
			<td >Gibco</td>
			<td >15290-026</td>
			<td >Potent and becomes toxic within a week so fresh complete HUVEC medium must be made up every week. Store at -20&#176;C in 1ml aliquots.</td>
		</tr>
		<tr >
			<td >Hydrocortisone</td>
			<td >Sigma</td>
			<td >H0135</td>
			<td>Stock is in ethanol. Store at -20&#176;C in 10&#181;l aliquots.</td>
		</tr>
		<tr >
			<td >Collagenase Type II</td>
			<td >Sigma</td>
			<td >C6885</td>
			<td>Dilute stock in PBS to a final concentration of 100mg/ml. Store at -20&#176;C in 100&#181;l aliquots.</td>
		</tr>
		<tr >
			<td >Hyaluronidase</td>
			<td >Sigma</td>
			<td >H3631</td>
			<td>Dilute stock in PBS to a final concentration of 20,000U/ml. Store at -20&#176;C in 100&#181;l aliquots.</td>
		</tr>
		<tr >
			<td >100&#181;m cell strainer for 50ml centifuge tube</td>
			<td >Scientific Lab Supplies (SLS)</td>
			<td >352360</td>
			<td >Other commercially available cell strainers (e.g. Greiner bio-one) can also be used.</td>
		</tr>
		<tr >
			<td >DMEM low glucose</td>
			<td >Biosera</td>
			<td >LM-D1102/500</td>
			<td>Warm in 37 &#176;C water bath before use.</td>
		</tr>
		<tr >
			<td >Penicillin/Streptomycin mix</td>
			<td >Sigma</td>
			<td >P4333</td>
			<td>Store at -20&#176;C in 1ml aliquots.</td>
		</tr>
		<tr >
			<td >25cm2 tissue culture flask</td>
			<td >SLS</td>
			<td >353109</td>
			<td></td>
		</tr>
		<tr >
			<td >75cm2 tissue culture flask</td>
			<td >SLS</td>
			<td >353136</td>
			<td></td>
		</tr>
		<tr >
			<td >Bone marrow mesenchymal stem cells vial</td>
			<td >Lonza</td>
			<td >PT-2501</td>
			<td >Store in liquid nitrogen upon arrival. Cells are at passage 2 upon arrival but are designated passage 0. Exapand to passage 3 and store in liquid nitrogen for later use.</td>
		</tr>
		<tr >
			<td >Mesenchymal stem cell growth medium (MSCGM)</td>
			<td >Lonza</td>
			<td >PT-3001</td>
			<td>Warm in 37 &#176;C water bath before use. For Cell Tracker Green staining use medium without FCS.</td>
		</tr>
		<tr >
			<td >EDTA (0.02%) solution</td>
			<td >Sigma</td>
			<td >E8008</td>
			<td>Store at 4&#176;C. Warm in 37&#176;C water bath before use.</td>
		</tr>
		<tr >
			<td >Trypsin solution</td>
			<td >Sigma</td>
			<td >T4424</td>
			<td>Store at -20&#176;C in 2ml aliquots. Thaw at room temperature and use immediately.</td>
		</tr>
		<tr >
			<td >Cryovials</td>
			<td >Greiner bio-one</td>
			<td>2019-02</td>
			<td>Keep on ice before adding before adding cell suspension.</td>
		</tr>
		<tr >
			<td >Mr. Frosty Freezing Container</td>
			<td >Nalgene</td>
			<td >5100-0001</td>
			<td >Store at room temperature. When adding cryovials with cells store at -80&#176;C for 24h before transfrring cells to liquid nitrogen.</td>
		</tr>
		<tr >
			<td >Ibidi u-Slide VI (0.4), T/C treated, sterile</td>
			<td >Ibidi</td>
			<td >IB-80606</td>
			<td >Alternative models include glass capillaries, Cellix Biochips (www.cellixltd.com), BioFlux Plates (www.fluxionbio.com/bioflux/) and GlycoTech parallel plate flow chambers (http://www.glycotech.com/apparatus/parallel.html).</td>
		</tr>
		<tr >
			<td >Cell tracker green dye</td>
			<td >Life technologies</td>
			<td >C2925</td>
			<td>Store in 5&#181;l aliquots at -20&#176;C. Dilute in 5ml prewarmed (at 37&#176;C) MSCGM.</td>
		</tr>
		<tr >
			<td >Cell counting chambers</td>
			<td >Nexcelom</td>
			<td >SD-100</td>
			<td>Alternatively a haemocytometer can be used.</td>
		</tr>
		<tr >
			<td >Cellometer auto T4 cell counter</td>
			<td >Nexcelom</td>
			<td >Auto T4-203-0238</td>
			<td></td>
		</tr>
		<tr >
			<td >Tumor necrosis factor &#945; (TNF&#945;)</td>
			<td >R&#38;D Systems</td>
			<td >210-TA-100</td>
			<td>Dilute stock in PBS to a final concentration of 100,000U/ml. Store at -80&#176;C in 10&#181;l aliquots.</td>
		</tr>
		<tr >
			<td >6-well, 0.4&#181;m PET Transwell filters</td>
			<td >SLS</td>
			<td >353090</td>
			<td></td>
		</tr>
		<tr >
			<td >K2-EDTA in 10ml tubes</td>
			<td >Sarstedt</td>
			<td ></td>
			<td>Store at room temperature.</td>
		</tr>
		<tr >
			<td >Histopaque 1119</td>
			<td >Sigma</td>
			<td >11191</td>
			<td>Store at 4&#176;C. Warm to room temperature before use.</td>
		</tr>
		<tr >
			<td >Histopaque 1077</td>
			<td >Sigma</td>
			<td >10771</td>
			<td>Store at 4&#176;C. Warm to room temperature before use.</td>
		</tr>
		<tr >
			<td >10ml round bottomed tube</td>
			<td >Appleton Woods</td>
			<td >SC211 142 AS</td>
			<td></td>
		</tr>
		<tr >
			<td >7.5% BSA Fraction V solution</td>
			<td >Life technologies</td>
			<td >15260-037</td>
			<td>Store at 4&#176;C.</td>
		</tr>
		<tr >
			<td >20ml Plastipak syringes</td>
			<td >BD falcon</td>
			<td >300613</td>
			<td></td>
		</tr>
		<tr >
			<td >5ml Plastipak syringes</td>
			<td >BD falcon</td>
			<td >302187</td>
			<td></td>
		</tr>
		<tr >
			<td >2ml Plastipak syringes</td>
			<td >BD falcon</td>
			<td >300185</td>
			<td></td>
		</tr>
		<tr >
			<td >3M hypo-allergenic surgical tape 9m x 2.5cm</td>
			<td >Micropore</td>
			<td >1530-1</td>
			<td>Use to secure the syringe tap onto the wall of the perspex chamber.</td>
		</tr>
		<tr >
			<td >Silicon rubber tubing, internal diameter/external diameter (ID/OD) of 1/3mm (thin tubing)</td>
			<td >Fisher Scientific</td>
			<td >FB68854</td>
			<td >Cut silicon tubing to the appropriate size. All tubing leading directly to the electronic microvalve must be thin.</td>
		</tr>
		<tr >
			<td >Silicon rubber tubing ID/OD of 2/4mm (thick tubing)</td>
			<td >Fisher Scientific</td>
			<td >FB68855</td>
			<td></td>
		</tr>
		<tr >
			<td >Portex Blue Line Manometer tubing</td>
			<td>Smiths</td>
			<td >200/495/200</td>
			<td>Tubing leading to the syringe pump.</td>
		</tr>
		<tr >
			<td >3-way stopcock</td>
			<td >BOC Ohmeda AB</td>
			<td ></td>
			<td></td>
		</tr>
		<tr >
			<td >Glass 50ml syringe for pump</td>
			<td >Popper Micromate</td>
			<td >550962</td>
			<td>Must be primed prior to use by removing any air bubbles.</td>
		</tr>
		<tr >
			<td >Glass coverslip</td>
			<td >Raymond A Lamb</td>
			<td ></td>
			<td>26x76mm coverslips made to order. Lot number 2440980.</td>
		</tr>
		<tr >
			<td >Parafilm gasket</td>
			<td >American National Can Company</td>
			<td ></td>
			<td >Cut a 26x76mm piece of parafilm using an aluminium template and cut a 20x4mm slot into it using a scalpel 10a. Gasket thickness is approximately 133&#181;m.</td>
		</tr>
		<tr >
			<td >Two perspex parallel plates</td>
			<td >Wolfson Applied Technology Laboratory</td>
			<td ></td>
			<td >Specially designed chamber consisting of parallel plates held together by 8 screws. The lower plate has a viewing slot cut out in the middle and a shallow recess milled to allow space for the coverslip, filter and gasket. The upper perspex plate has an inlet and outlet hole positioned over the flow channel.</td>
		</tr>
		<tr >
			<td >Electronic 3-way microvalve with min. dead space</td>
			<td >Lee Products Ltd.</td>
			<td >LFYA1226032H</td>
			<td>Electronically connected to a 12 volt DC power supply.</td>
		</tr>
		<tr >
			<td >Syringe pump for infusion/withdrawal (PHD2000)</td>
			<td >Harvard Apparatus</td>
			<td >70-2001</td>
			<td>Set the diameter to 29mm and refill (flow) rate.</td>
		</tr>
		<tr >
			<td >L-shaped connector</td>
			<td >Labhut</td>
			<td >LE876</td>
			<td>To attach to the inlet and outlet ports onto the Ibidi microslide channel.</td>
		</tr>
		<tr >
			<td >Video camera</td>
			<td >Qimaging</td>
			<td >01-QIC-F-M-12-C</td>
			<td>Connected to a computer which enables digitall videos to be recorded.</td>
		</tr>
		<tr >
			<td >Image-Pro Plus 7.0</td>
			<td >Media Cybernetics</td>
			<td >41N70000-61592</td>
			<td >For data analysis. Manually tag cells displaying the different behaviors. Track cells for analysis of rolling and migration velocities.</td>
		</tr>
		<tr >
			<td ></td>
			<td ></td>
			<td ></td>
			<td>Refer to product datasheets for details on hazards of using the reagents described here.</td>
		</tr>
	</tbody>
</table>

analyzing the effects of stromal cells on the recruitment of leukocytes from flow

Stromal cells regulate the recruitment of circulating leukocytes during inflammation through cross-talk with neighboring endothelial cells. Here we describe two in vitro &#8220;vascular&#8221; models for studying the recruitment of circulating neutrophils from flow by inflamed endothelial cells. A major advantage of these models is the ability to analyze each step in the leukocyte adhesion cascade in order, as would occur in vivo. We also describe how both models can be adapted to study the role of stromal cells, in this case mesenchymal stem cells (MSC), in regulating leukocyte recruitment.
Primary endothelial cells were cultured alone or together with human MSC in direct contact on Ibidi microslides or on opposite sides of a Transwell filter for 24 hr. Cultures were stimulated with tumor necrosis factor alpha (TNF&#945;) for 4 hr and incorporated into a flow-based adhesion assay. A bolus of neutrophils was perfused over the endothelium for 4 min. The capture of flowing neutrophils and their interactions with the endothelium was visualized by phase-contrast microscopy.
In both models, cytokine-stimulation increased endothelial recruitment of flowing neutrophils in a dose-dependent manner. Analysis of the behavior of recruited neutrophils showed a dose-dependent decrease in rolling and a dose-dependent increase in transmigration through the endothelium. In co-culture, MSC suppressed neutrophil adhesion to TNF&#945;-stimulated endothelium.
Our flow based-adhesion models mimic the initial phases of leukocyte recruitment from the circulation. In addition to leukocytes, they can be used to examine the recruitment of other cell types, such as therapeutically administered MSC or circulating tumor cells. Our multi-layered co-culture models have shown that MSC communicate with endothelium to modify their response to pro-inflammatory cytokines, altering the recruitment of neutrophils. Further research using such models is required to fully understand how stromal cells from different tissues and conditions (inflammatory disorders or cancer) influence the recruitment of leukocytes during inflammation.

Initially, we analyzed the effect of stimulating EC with TNF&#945; on the recruitment of neutrophils from flow using the Ibidi microslide model (Section 7 - 9). In the absence of TNF&#945;, little if any neutrophils adhered to the endothelial monolayer (Figure 2A). This was expected, as untreated/resting EC do not express the necessary adhesion molecules (selectins) or chemokines to support binding25,26. In contrast, cytokine-stimulation significantly increased neutrophil adhe...

Watch this Scientific Journal Video about Analyzing the Effects of Stromal Cells on the Recruitment of Leukocytes from Flow at JoVE.com

Analyzing the Effects of Stromal Cells on the Recruitment of Leukocytes from Flow

The ability of inflamed endothelium to recruit leukocytes from flow is regulated by mesenchymal stromal cells. We describe two in vitro models incorporating primary human cells that can be used to assess neutrophil recruitment from flow and examine the role that mesenchymal stromal cells play in regulating this process.

Stromal cells regulate the recruitment of circulating leukocytes during inflammation through cross-talk with neighboring endothelial cells. Here we ...

analyzing-effects-stromal-cells-on-recruitment-leukocytes-from

Research

JoVE Journal

Immunology and Infection

Isolation and Analysis of Brain-sequestered Leukocytes from Plasmodium berghei ANKA-infected Mice

We describe a method for isolation and characterization of adherent inflammatory cells from brain blood vessels of P. berghei ANKA-infected mice. Infection of susceptible mouse-strains with this parasite strain results in the induction of experimental cerebral malaria, a neurologic syndrome that recapitulates certain important aspects of Plasmodium falciparum-mediated severe malaria in humans 1,2 . Mature forms of blood-stage malaria express parasitic proteins on the surface of the infected erythrocyte, which allows them to bind to vascular endothelial cells. This process induces obstructions in blood flow, resulting in hypoxia and haemorrhages 3 and also stimulates the recruitment of inflammatory leukocytes to the site of parasite sequestration.
Unlike other infections, i.e neutrotopic viruses4-6, both malaria-parasitized red blood cells (pRBC) as well as associated inflammatory leukocytes remain sequestered within blood vessels rather than infiltrating the brain parenchyma. Thus to avoid contamination of sequestered leukocytes with non-inflammatory circulating cells, extensive intracardial perfusion of infected-mice prior to organ extraction and tissue processing is required in this procedure to remove the blood compartment. After perfusion, brains are harvested and dissected in small pieces. The tissue structure is further disrupted by enzymatic treatment with Collagenase D and DNAse I. The resulting brain homogenate is then centrifuged on a Percoll gradient that allows separation of brain-sequestered leukocytes (BSL) from myelin and other tissue debris. Isolated cells are then washed, counted using a hemocytometer and stained with fluorescent antibodies for subsequent analysis by flow cytometry.
This procedure allows comprehensive phenotypic characterization of inflammatory leukocytes migrating to the brain in response to various stimuli, including stroke as well as viral or parasitic infections. The method also provides a useful tool for assessment of novel anti-inflammatory treatments in pre-clinical animal models.

Isolation and Analysis of Brain-sequestered Leukocytes from Plasmodium berghei ANKA-infected Mice

A method for isolation of adherent inflammatory leukocytes from brain blood vessels of Plasmodium berghei ANKA-infected mice is described. The method allows quantification as well as phenotypic characterization of isolated leukocytes after staining with fluorescent antibodies and subsequent analysis by flow cytometry.

We describe a method for isolation and  characterization of adherent inflammatory cells from brain blood vessels of P. berghei ANKA-infected mice. ...

Investigating the Effects of Probiotics on Pneumococcal Colonization Using an In Vitro Adherence Assay

Adherence of Streptococcus pneumoniae (the pneumococcus) to the epithelial lining of the nasopharynx can result in colonization and is considered a prerequisite for pneumococcal infections such as pneumonia and otitis media. In vitro adherence assays can be used to study the attachment of pneumococci to epithelial cell monolayers and to investigate potential interventions, such as the use of probiotics, to inhibit pneumococcal&#160;colonization.&#160;The protocol described here is used to investigate the effects of the probiotic Streptococcus salivarius on the adherence of pneumococci to the human epithelial cell line CCL-23 (sometimes referred to as HEp-2 cells). The assay involves three main steps: 1) preparation of epithelial and bacterial cells, 2) addition of bacteria to epithelial cell monolayers, and 3) detection of adherent pneumococci by viable counts (serial dilution and plating) or quantitative real-time PCR (qPCR). This technique is relatively straightforward and does not require specialized equipment other than a tissue culture setup. The assay can be used to test other probiotic species and/or potential inhibitors of pneumococcal colonization and can be easily modified to address other scientific questions regarding pneumococcal adherence and invasion.

Investigating the Effects of Probiotics on Pneumococcal Colonization Using an In Vitro Adherence Assay

In vitro adherence assays can be used to study the attachment of Streptococcus pneumoniae to epithelial cell monolayers and to investigate potential interventions such as the use of probiotics for inhibiting pneumococcal colonization.

Adherence of Streptococcus pneumoniae (the pneumococcus) to the epithelial lining of the nasopharynx can result in colonization and is considered a ...

Isolation of Leukocytes from the Human Maternal-fetal Interface

Pregnancy is characterized by the infiltration of leukocytes in the reproductive tissues and at the maternal-fetal interface (decidua basalis and decidua parietalis). This interface is the anatomical site of contact between maternal and fetal tissues; therefore, it is an immunological site of action during pregnancy. Infiltrating leukocytes at the maternal-fetal interface play a central role in implantation, pregnancy maintenance, and timing of delivery. Therefore, phenotypic and functional characterizations of these leukocytes will provide insight into the mechanisms that lead to&#160;pregnancy disorders. Several protocols have been described in order to isolate infiltrating leukocytes from the decidua basalis and decidua parietalis; however, the lack of consistency in the reagents, enzymes, and times of incubation makes it difficult to compare these results. Described herein is&#160;a novel approach that combines the use of gentle mechanical and enzymatic dissociation techniques to preserve the viability and integrity of extracellular and intracellular markers in leukocytes isolated from the human tissues at the maternal-fetal interface. Aside from immunophenotyping, cell culture, and cell sorting, the future applications of this protocol are numerous and varied. Following this protocol, the isolated leukocytes can be used to determine DNA methylation, expression of target genes, in vitro leukocyte functionality (i.e., phagocytosis, cytotoxicity, T-cell proliferation, and plasticity, etc.), and the production of reactive oxygen species at the maternal-fetal interface. Additionally, using the described protocol, this laboratory has been able to describe new and rare leukocytes at the maternal-fetal interface.

Described herein is a protocol to isolate and further study the infiltrating leukocytes of the decidua basalis and decidua parietalis - the human maternal-fetal interface. This protocol maintains the integrity of cell surface markers and yields enough viable cells for downstream applications as proven by flow cytometry analysis.

Pregnancy is characterized by the infiltration of leukocytes in the reproductive tissues and at the maternal-fetal interface (decidua basalis and decidua ...

Isolation of Leukocytes from the Murine Tissues at the Maternal-Fetal Interface

Immune tolerance in pregnancy requires that the immune system of the mother undergoes distinctive changes in order to accept and nurture the developing fetus. This tolerance is initiated during coitus, established during fecundation and implantation, and maintained throughout pregnancy. Active cellular and molecular mediators of maternal-fetal tolerance are enriched at the site of contact between fetal and maternal tissues, known as the maternal-fetal interface, which includes the placenta and the uterine and decidual tissues. This interface is comprised of stromal cells and infiltrating leukocytes, and their abundance and phenotypic characteristics change over the course of pregnancy. Infiltrating leukocytes at the maternal-fetal interface include neutrophils, macrophages, dendritic cells, mast cells, T cells, B cells, NK cells, and NKT cells that together create the local micro-environment that sustains pregnancy. An imbalance among these cells or any inappropriate alteration in their phenotypes is considered a mechanism of disease in pregnancy. Therefore, the study of leukocytes that infiltrate the maternal-fetal interface is essential in order to elucidate the immune mechanisms that lead to pregnancy-related complications. Described herein is a protocol that uses a combination of gentle mechanical dissociation followed by a robust enzymatic disaggregation with a proteolytic and collagenolytic enzymatic cocktail to isolate the infiltrating leukocytes from the murine tissues at the maternal-fetal interface. This protocol allows for the isolation of high numbers of viable leukocytes (&#62;70%) with sufficiently conserved antigenic and functional properties. Isolated leukocytes can then be analyzed by several techniques, including immunophenotyping, cell sorting, imaging, immunoblotting, mRNA expression, cell culture, and in vitro functional assays such as mixed leukocyte reactions, proliferation, or cytotoxicity assays.

Described herein is a protocol to isolate and analyze the infiltrating leukocytes of tissues at the maternal-fetal interface (uterus, decidua, and placenta) of mice. This protocol maintains the integrity of most cell surface markers and yields enough viable cells for downstream applications including flow cytometry analysis.

Immune tolerance in pregnancy requires that the immune system of the mother undergoes distinctive changes in order to accept and nurture the developing ...

The Use of Flow Cytometry to Assess the State of Chromatin in T Cells

During a proper immune response, quiescent T cells become activated upon antigen presentation to their antigen-specific T cell receptor. This leads to clonal proliferation of only those T cells that bear a receptor that recognizes the antigen. Chromatin decondensation is a hallmark of T cell activation and is required for T cells to acquire the ability to proliferate after antigen engagement. This change in chromatin condensation can be detected using antibodies raised against histone proteins. These antibodies cannot bind to their epitopes in na&#239;ve T cells as well as they can in activated T cells. We describe how to simultaneously stain T cell-specific surface markers, track viability with a fixable dead cell stain, and measure chromatin status via intracellular staining of Histone H3 proteins. Stained cells are analyzed by flow cytometry and chromatin condensation status is measured as the mean fluorescence intensity (MFI) of the Histone H3 stain. Chromatin decondensation during T cell activation is demonstrated as an increase in the MFI

Flow cytometry can be utilized to assess the state of chromatin within T cells. This protocol allows scientists to interpret evidence of chromatin decondensation during T cell activation demonstrated by an increase in the mean florescence intensity (MFI) of fluorescent Histone H3 antibodies

During a proper immune response, quiescent T cells become activated upon antigen presentation to their antigen-specific T cell receptor. This leads to ...

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 ...

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

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

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

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

Flow Cytometric Analysis of Particle-bound Bet v 1 Allergen in PM10

Flow cytometry is a method widely used to quantify suspended solids such as cells or bacteria in a size range from 0.5 to several tens of micrometers in diameter. In addition to a characterization of forward and sideward scatter properties, it enables the use of fluorescent labeled markers like antibodies to detect respective structures. Using indirect antibody staining, flow cytometry is employed here to quantify birch pollen allergen (precisely Bet v 1)-loaded particles of 0.5 to 10 &#181;m in diameter in inhalable particulate matter (PM10, particle size &#8804;10 &#181;m in diameter). PM10 particles may act as carriers of adsorbed allergens possibly transporting them to the lower respiratory tract, where they could trigger allergic reactions.
So far the allergen content of PM10 has been studied by means of enzyme linked immunosorbent assays (ELISAs) and scanning electron microscopy. ELISA measures the dissolved and not the particle-bound allergen. Compared to scanning electron microscopy, which can visualize allergen-loaded particles, flow cytometry may additionally quantify them. As allergen content of ambient air can deviate from birch pollen count, allergic symptoms might perhaps correlate better with allergen exposure than with pollen count. In conjunction with clinical data, the presented method offers the opportunity to test in future experiments whether allergic reactions to birch pollen antigens are associated with the Bet v 1 allergen content of PM10 particles &#62;0.5 &#181;m.

Here, we present a protocol to quantify allergen-loaded particles by flow cytometry. Ambient particulate matter particles may act as carriers of adsorbed allergens. We show here that flow cytometry, a method widely used to characterize suspended solids &#62;0.5 &#181;m in diameter, can be used to measure these allergen-loaded particles.

Flow cytometry is a method widely used to quantify suspended solids such as cells or bacteria in a size range from 0.5 to several tens of micrometers in ...

Visualizing the Effects of Sputum on Biofilm Development Using a Chambered Coverglass Model

Biofilms consist of groups of bacteria encased in a self-secreted matrix. They play an important role in industrial contamination as well as in the development and persistence of many health related infections. One of the most well described and studied biofilms in human disease occurs in chronic pulmonary infection of cystic fibrosis patients. When studying biofilms in the context of the host, many factors can impact biofilm formation and development. In order to identify how host factors may affect biofilm formation and development, we used a static chambered coverglass method to grow biofilms in the presence of host-derived factors in the form of sputum supernatants. Bacteria are seeded into chambers and exposed to sputum filtrates. Following 48 hr of growth, biofilms are stained with a commercial biofilm viability kit prior to confocal microscopy and analysis. Following image acquisition, biofilm properties can be assessed using different software platforms. This method allows us to visualize key properties of biofilm growth in presence of different substances including antibiotics.

This protocol describes the visualization of biofilm development following exposure to host-factors using a slide chamber model. This model allows for direct visualization of biofilm development as well as analysis of biofilm parameters using computer software programs.

Biofilms consist of groups of bacteria encased in a self-secreted matrix. They play an important role in industrial contamination as well as in the ...

Laminar Flow-based Assays to Investigate Leukocyte Recruitment on Cultured Vascular Cells and Adherent Platelets

The recruitment of leukocytes upon injury or inflammation to sites of injury or tissue damage has been investigated during recent decades and has resulted in the concept of the leukocyte adhesion cascade. However, the exact molecular mechanisms involved in leukocyte recruitment have not yet been fully identified. Since leukocyte recruitment remains an important subject in the field of infection, inflammation, and (auto-) immune research, we present a straightforward laminar flow-based assay to study underlying mechanisms of the adhesion, de-adhesion, and transmigration of leukocytes under venous and arterial flow regimes. The in vitro assay can be used to study the molecular mechanisms that underlie the interactions between leukocytes and their cellular partners in different models of vascular inflammation. This protocol describes a laminar flow-based assay using a parallel-flow chamber and an inverted phase contrast microscope connected to a camera to study the interactions of leukocytes and endothelial cells or platelets, which can be visualized and recorded then analyzed offline. Endothelial cells, platelets, or leukocytes can be pretreated with inhibitors or antibodies to determine the role of specific molecules during this process. Shear conditions, i.e. arterial or venous shear stress, can be easily adapted by the viscosity and flow rate of the perfused fluids and the height of the channel.

Leukocytes avidly interact with vascular cells and platelets after vessel wall injury or during inflammation. Here, we describe a straightforward laminar flow-based assay to characterize the molecular mechanisms that underlie the interactions between leukocytes and their cellular partners.

The recruitment of leukocytes upon injury or inflammation to sites of injury or tissue damage has been investigated during recent decades and has resulted ...