Diese Arbeit wurde vom NIH R01-3155 bis 53.502 und Washington University-Pfizer Biomedical Research Agreement unterstützt.

1. Tierische Zubereitung: Dieses Protokoll verwendet erwachsenen weiblichen erwachsenen LysM-eGFP Mäusen, bei denen Neutrophilen und Makrophagen fluoreszierend sind durch die Expression von eGFP 1 bezeichnet. <ol class="lalpha"><li> Labeling Blutgefäße: Zur Visualisierung Blutgefäße, 15μl von nicht gezielten Quantenpunkte (655nm) werden in 100 ul PBS verdünnt und intravenös in die Maus 10-30 min vor Imaging injiziert. </li><li> Anästhesie: <ol><li> Platzieren Sie die Maus in die Induktion Kammer des Veterinär-Inhalationsnarkose System (Noble Medical Service, Inc). </li><li> Setzen Sie den Verdampfer auf 3-4% Isofluran und 100% Sauerstoff Gasstrom auf ~ 1 L / min. Um Fehlbedienungen zu vermeiden Anästhesie Überdosierung genau beobachten das Tier bis zum hinteren Fuß Prise Reflex ist verloren. </li><li> Anästhesie ist bei 1,5 gehalten ~ 2% Isofluran und feine während der Bildgebung abgestimmt, um die Atmung Artefakte wie nötig zu minimieren. Die Atemfrequenz der Maus ist sorgfältig in der Imaging-Session überwacht, um eine angemessene Ebene der Narkose zu versichern. </li><li> Puralube Veterinär Salbe ist für die Augen, um zu verhindern Trocknung angewendet. </li><li> Die Maus ist an einem geregelten 36 aufgesetzt ° C Heizkissen (Braintree Scientific) während der Injektionen und Bildbearbeitung, um eine Unterkühlung zu verhindern. </li><li> Um zu verhindern, Dehydratation, ist die Maus 100 ul PBS sc alle 1-2 Stunden gegeben. </li></ol></li><li> Delivering eine entzündliche Reize zu Leukozytenrekrutierung induzieren: <ol><li> Platzieren Sie die Maus auf dem OP-Bühne und Tupfer der Fußsohle mit 70% Ethanol. </li><li> Biegen Sie die Nadel einer Insulin-Spritze ~ 90 Grad in der Nähe der Schräge der Injektion zu erleichtern und verbessern die Genauigkeit der Lieferung Tiefe. </li><li> Legen Sie die Spritze mit 0,5 ug E.coli Biopartikeln in 1μl PBS verdünnt. Dies kann in den Deckel eines Mikrozentrifugenröhrchen zu erleichtern, um den Tropfen Last durchgeführt werden. </li><li> Halten Sie den Fuß mit einer gebogenen Pinzette und führen Sie die Nadel vorsichtig durch die Haut mit der Fase nach oben, bis sie knapp unter der Haut ist. </li><li> Injizieren Sie langsam und halten Sie ihn 5 Sekunden lang zu verhindern, dass wieder spülen. </li></ol></li></ol> 2. Imaging Bühnenaufbau: Die Imaging-Plattform besteht aus einer Aluminium-Platte mit einem kreisrunden Loch in der Mitte abgeschnitten. Ein großes Deckglas wird an der Unterseite der Platte und ein Gummi-O-Ring ist an der Oberseite geklebt, um eine flüssigkeitsdichte vertiefte Kammer zu schaffen, um die Hinterpfote Platz geklebt. Die Aluminiumplatte wird auf 36 ° C über zwei Heizelemente an der Oberseite der Platte erwärmt. <ol class="lalpha"><li> Legen Sie die Maus auf den vorgewärmten Bildgebung Bühne und halten Sie die Maustaste ist die Kerntemperatur des Körpers mit dem 36 ° C Erwärmung pad. </li><li> Sichern Sie die Pfote an den Deckglas des abbildenden Kammer mit einer dünnen Schicht von Sekundenkleber. </li><li> Waschen Sie die Pfote zweimal, um eine schwimmende Bits Kleber zu entfernen und füllen Sie dann die Kammer mit frischem PBS (bis 36 vorgewärmten ° C). </li></ol> Mäuse können für bis zu 4 Stunden ohne aus dem Tier die Lebensfähigkeit abgebildet werden. Der Fuß kann leicht mit wenig Aceton und Mäuse für die Längs-Imaging-Studien wieder freigegeben werden. Allerdings ist in diesem Fall empfehlen wir die Bildgebung Zeitraum bis &lt;2 Stunden und wartet 24-48 h zwischen den Sitzungen, um das Risiko der Narkose Überdosierung oder Austrocknung zu minimieren. 3. Imaging Acquisition Die Zwei-Photonen-Mikroskop (2P-Mikroskop) im Sinne dieses Protokolls ist eine custom-built Dual-Laser-Video-Rate-System bestehend aus einem aufrechten Mikroskop. Das System ist mit zwei Ti ausgestattet: Sapphire Laser, vier Haupt-on Bi-Alkali-PMTs für das simultane 3 und 4-Kanal-Akquisitionen und ein 20x Wasserimmersionsobjektiv (Olympus, 20x/0.95 NA). <ol class="lalpha"><li> Tune the Chameleon XR Ti: Saphir-Laser (Coherent Inc.), um 890-900nm. </li><li> Verwenden 480nm und 560nm dichroitische Spiegel (SemRoc) zu drei Kanäle trennen: blau (&lt;480 nm, Second Harmonic Generation-Signal), Grün (480-560nm, LysM-eGFP positiven Neutrophilen) und Rot (&gt; 560 nm, Quantenpunkt bezeichnet Blutgefäße ). Alternativ kann die 560nm-Filter mit einem 570nm Filter E. unterscheiden ersetzt werden coli Biopartikeln (576nm Biopartikeln erscheint orange) von 655nm Quantenpunkte (erscheint tiefrot). </li><li> Vorsichtig das Ziel in die PBS und konzentrieren sich auf ein Schiff der Zehe. </li><li> Mit der Aufnahmegeschwindigkeit, die bei Video-Rate (30f/sec) und mit der zweiten harmonischen Signals ausgehend von Kollagen als ein Gewebe Wahrzeichen, schnell Umfrage des Gewebes (bei Video-rate Aufnahmegeschwindigkeit), um ein Blutgefäß von Interesse (eine lokalisieren mit sichtbaren lysM-eGFP Neutrophile). </li><li> Stellen Sie den Gain auf der PMTs einer Farbtrennung zu optimieren und die Höhe der Laser benötigt, um ein ausreichendes Signal gegenüber dem Hintergrund zu erreichen (werdenAchten Sie darauf, um das Bild zu sättigen!). </li><li> Sobald Flächenbereich der Interessen befindet, beginnen Zeitraffer-Bildgebung. Zeitraffer-Imaging kann mit zwei verschiedenen zeitlichen Auflösungen durchgeführt werden. Für die Bildgebung Zellrollen und Adhäsion und in Echtzeit innerhalb von Blutgefäßen, so erwerben wir 30f/sec an einem z-Ebene. Zur Dokumentation Zelle Extravasation und Migration in das Parenchym führen wir 3D Zeitraffer-Bildgebung. Ein typisches Übernahme-Protokoll wird von durchschnittlich 15 Frames pro Z-Schritt und den Erwerb von 21 aufeinanderfolgenden 2.5μm z-Schritte mit einem Volumen von 200-225 50 um bei 30 Sekunden-Intervallen bestehen. </li><li> Sobald die Daten-Dateien auf dem Labor-Server gespeichert sind, können Imaris oder Volocity Software verwendet, um multi-dimensionale Darstellung und Zell-Tracking 2, 3 durchzuführen. </li></ol> 4. Repräsentative Ergebnisse 1.Real-Zeit (30f/sec) vorstellen, der neutrophilen Rollen entlang der Gefäße bei 200x. Zeitraffer-Aufnahme zeigt Neutrophilen, in grün, Rollen entlang des Endothels der Blutgefäße etwa 10 Minuten nach der Infektion mit Listeria monocytogenes, in rot dargestellt. Kollagenfasern im Bindegewebe erscheinen in blau. <a href="http://www.jove.com/files/ftp_upload/2062/2062_Miller_Movie1.mov">Bitte klicken Sie hier, um das Video zu sehen.</a> 2.Time Zeitraffer 3D-Bildgebung von neutrophilen Rekrutierung Dynamik bei 200x. Typische neutrophilen Rekrutierung aus dem Verkehr und Migration durch entzündetes Gewebe wird angezeigt. <a href="http://www.jove.com/files/ftp_upload/2062/2062_Miller_Movie2.mov">Bitte klicken Sie hier, um das Video zu sehen.</a>

<ol>
	<li>Faust, N., Varas, F., Kelly, L. M., Heck, S., Graf, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insertion+of+enhanced+green+fluorescent+protein+into+the+lysozyme+gene+creates+mice+with+green+fluorescent+granulocytes+and+macrophages.">Insertion of enhanced green fluorescent protein into the lysozyme gene creates mice with green fluorescent granulocytes and macrophages.</a> Blood. 96, 719-726 (2000).</li><li>Zinselmeyer, B. H., Lynch, J. N., Zhang, X., Aoshi, T., Miller, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Video-rate+two-photon+imaging+of+mouse+footpad+-+a+promising+model+for+studying+leukocyte+recruitment+dynamics+during+inflammation.">Video-rate two-photon imaging of mouse footpad - a promising model for studying leukocyte recruitment dynamics during inflammation.</a> Inflamm Res. 57, 93-96 (2008).</li><li>Zinselmeyer, B. H., Dempster, J., Wokosin, D. L., Cannon, J. J., Pless, R., Parker, I., Miller, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+16.+Two-photon+microscopy+and+multidimensional+analysis+of+cell+dynamics.">Chapter 16. Two-photon microscopy and multidimensional analysis of cell dynamics.</a> Methods Enzymol. 461, 349-378 (2009).</li><li>Gray, D. F., Jennings, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Allergy+in+experimental+mouse+tuberculosis.">Allergy in experimental mouse tuberculosis.</a> Am Rev Tuberc. 72, 171-195 (1955).</li><li>Lin, A., Loughman, J. A., Zinselmeyer, B. H., Miller, M. J., Caparon, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Streptolysin+S+inhibits+neutrophil+recruitment+during+the+early+stages+of+Streptococcus+pyogenes+infection.+Infect+Immun.">Streptolysin S inhibits neutrophil recruitment during the early stages of Streptococcus pyogenes infection. Infect Immun.</a> 77, 5190-5201 (2009).</li><li>Smith, C. J., Zhang, Y., Koboldt, C. M., Muhammad, J., Zweifel, B. S., Shaffer, A., Talley, J. J., Masferrer, J. L., Seibert, K., Isakson, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacological+analysis+of+cyclooxygenase-1+in+inflammation.">Pharmacological analysis of cyclooxygenase-1 in inflammation.</a> Proc Natl Acad Sci U S A. 95, 13313-13318 (1998).</li><li>Wipke, B. T., Allen, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Essential+role+of+neutrophils+in+the+initiation+and+progression+of+a+murine+model+of+rheumatoid+arthritis.">Essential role of neutrophils in the initiation and progression of a murine model of rheumatoid arthritis.</a> J Immunol. 167, 1601-1608 (2001).</li><li>Baez, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+open+cremaster+muscle+preparation+for+the+study+of+blood+vessels+by+in+vivo+microscopy.">An open cremaster muscle preparation for the study of blood vessels by in vivo microscopy.</a> Microvasc Res. 5, 384-394 (1973).</li><li>Mempel, T. R., Scimone, M. L., Mora, J. R., von Andrian, U. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=in+vivo+imaging+of+leukocyte+trafficking+in+blood+vessels+and+tissues.">in vivo imaging of leukocyte trafficking in blood vessels and tissues.</a> Curr Opin Immunol. 16, 406-417 (2004).</li><li>Miller, M. J., Wei, S. H., Cahalan, M. D., Parker, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Autonomous+T+cell+trafficking+examined+in+vivo+with+intravital+two-photon+microscopy.">Autonomous T cell trafficking examined in vivo with intravital two-photon microscopy.</a> Proc Natl Acad Sci U S A. 100, 2604-2609 (2003).</li></ol>

Alle Experimente wurden nach Protokollen von der Animal Studies Ausschuss der Washington University in St. Louis genehmigt durchgeführt.

In diesem Video zeigen wir, Protokoll der Verfahren für nicht-invasive Bildgebung von 2P Leukozytenrekrutierung in Reaktion auf Entzündungen. Die Fußsohle ist ein klassisches physiologischen Ort für das Studium Entzündungen wie Allergien, Infektionen und Autoimmunerkrankungen 4-7. 2P Bildgebung liefert ein detailliertes Bild über verschiedene Schritte in Leukozyten Menschenhandel Wege, von Walz-und Haftung in den Blutgefäßen die Chemotaxis zu den Orten der Effektor-Funktio...

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		<th>Catalogue Number</th>
		<th>Comment</th>
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<td>Isoflurane, USP</td>
<td>&nbsp;</td>
<td>Butler Animal Health Supply</td>
<td>029405</td>
<td>&nbsp;</td>
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<td>655nm non-targeted quantum dots</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>Q21021MP</td>
<td>&nbsp;</td>
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<td>Tetramathylrhodamine conjugated E. coli BioParticles </td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>E2862</td>
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<td>Listeria monocytogenes (Lm)</td>
<td>&nbsp;</td>
<td>Reference 2</td>
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<td>Quick gel</td>
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<td>Duro</td>
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<td>Puralube Vet Ointment </td>
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<td>Insulin syringes</td>
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non-invasive imaging of leukocyte homing and migration in vivo

Zwei-Photonen (2P)-Mikroskopie ist eine hochauflösende bildgebende Verfahren, die im Großen und Ganzen wurde von Biologen angepasst. Der Wert der 2P-Mikroskopie ist, dass es reiche raumzeitlichen Informationen über Zell Verhaltensweisen innerhalb intakte Gewebe und in lebenden Mäusen liefert. Rekrutierung von Leukozyten spielt eine bedeutende Rolle in Immunabwehr gegen Infektionen und wenn deaktiviert, kann zu entzündlichen und Autoimmun-Erkrankungen beitragen. Studieren Leukozytenrekrutierung in vivo ist technisch anspruchsvoll, da die Zellen schneller sind, die innerhalb Schiffe tief im Lichtstreuung Gewebe entfernt. Bis heute verlangen die meisten intravital bildgebende chirurgische Vorbereitung auf die Blutgefäße und Gewebe freizulegen. Um zu vermeiden, die Gewebeschäden und Entzündungen, die durch Operation selbst induziert, hier beschreiben wir eine nicht-invasive Single-Cell-Imaging-Ansatz, mit dem Leukozyten-Handel mit der Maus Fußballen und Phalangen Studie werden können. Wir besprechen die technischen Aspekte unserer 2P Bildgebung Vorbereitung und gehen den Leser durch ein typisches Experiment von der ersten bis zur Ausführung und Datensammlung eingestellt.

Watch this Scientific Journal Video about Non-invasive Imaging of Leukocyte Homing and Migration in vivo at JoVE.com

Non-invasive Imaging of Leukocyte Homing and Migration in vivo

Hier beschreiben wir eine nicht-invasive Zwei-Photonen (2P)-Mikroskopie Ansatz zur Untersuchung Leukozyten homing in der Maus Fußballen. Wir besprechen die technischen Aspekte unserer Tissue Imaging Vorbereitung und gehen den Leser durch ein typisches Experiment von der ersten bis zur Ausführung und Datensammlung eingestellt.

Nicht-invasive Bildgebung von Leukozyten Homing und Migration In vivo</em

Two-photon (2P) microscopy is a high resolution imaging technique that has been broadly adapted by biologists.  The value of 2P microscopy is that it ...

non-invasive-imaging-of-leukocyte-homing-and-migration-in-vivo

Research

JoVE Journal

Immunology and Infection

Non-invasive Imaging of Leukocyte Homing and Migration in vivo

12.7K Aufrufe.  Washington University in St. Louis. Hier beschreiben wir eine nicht-invasive Zwei-Photonen (2P)-Mikroskopie Ansatz zur Untersuchung Leukozyten homing in der Maus Fußballen. Wir besprechen die technischen Aspekte unserer Tissue Imaging Vorbereitung und gehen den Leser durch ein typisches Experiment von der ersten bis zur Ausführung und Datensammlung eingestellt.

Serie: Non-invasive Imaging of Leukocyte Homing and Migration in vivo

Competitive Homing Assays to Study Gut-tropic T Cell Migration

In order to exert their function lymphocytes need to leave the blood and migrate into different tissues in the body. Lymphocyte adhesion to endothelial cells and tissue extravasation is a multistep process controlled by different adhesion molecules (homing receptors) expressed on lymphocytes and their respective ligands (addressins) displayed on endothelial cells 1 2. Even though the function of these adhesion receptors can be partially studied ex vivo, the ultimate test for their physiological relevance is to assess their role during in vivo lymphocyte adhesion and migration. Two complementary strategies have been used for this purpose: intravital microscopy (IVM) and homing experiments. Although IVM has been essential to define the precise contribution of specific adhesion receptors during the adhesion cascade in real time and in different tissues, IVM is time consuming and labor intensive, it often requires the development of sophisticated surgical techniques, it needs prior isolation of homogeneous cell populations and it permits the analysis of only one tissue/organ at any given time. By contrast, competitive homing experiments allow the direct and simultaneous comparison in the migration of two (or even more) cell subsets in the same mouse and they also permit the analysis of many tissues and of a high number of cells in the same experiment.
Here we describe the classical competitive homing protocol used to determine the advantage/disadvantage of a given cell type to home to specific tissues as compared to a control cell population. We chose to illustrate the migratory properties of gut-tropic versus non gut-tropic T cells, because the intestinal mucosa is the largest body surface in contact with the external environment and it is also the extra-lymphoid tissue with the best-defined migratory requirements. Moreover, recent work has determined that the vitamin A metabolite all-trans retinoic acid (RA) is the main molecular mechanism responsible for inducing gut-specific adhesion receptors (integrin a4b7and chemokine receptor CCR9) on lymphocytes. Thus, we can readily generate large numbers of gut-tropic and non gut-tropic lymphocytes ex vivoby activating T cells in the presence or absence of RA, respectively, which can be finally used in the competitive homing experiments described here.

Competitive homing experiments allow to directly assessing the migratory properties of two different cell populations in a single mouse. Here we illustrate this procedure by comparing the migration of ex vivo-generated gut-tropic versus non-gut tropic T cells.

Competitive Homing-Assays auf Gut-trope T-Zell-Migration Study

In order to exert their function lymphocytes need to leave the blood and migrate into different tissues in the body. Lymphocyte adhesion to endothelial ...

Forschung

Immunologie und Infektion

Imaging Leukocyte Adhesion to the Vascular Endothelium at High Intraluminal Pressure

Worldwide, hypertension is reported to be in approximately a quarter of the population and is the leading biomedical risk factor for mortality worldwide. In the vasculature hypertension is associated with endothelial dysfunction and increased inflammation leading to atherosclerosis and various disease states such as chronic kidney disease2, stroke3 and heart failure4. An initial step in vascular inflammation leading to atherogenesis is the adhesion cascade which involves the rolling, tethering, adherence and subsequent transmigration of leukocytes through the endothelium. Recruitment and accumulation of leukocytes to the endothelium is mediated by an upregulation of adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1), intracellular cell adhesion molecule-1 (ICAM-1) and E-selectin as well as increases in cytokine and chemokine release and an upregulation of reactive oxygen species5. In vitro methods such as static adhesion assays help to determine mechanisms involved in cell-to-cell adhesion as well as the analysis of cell adhesion molecules. Methods employed in previous in vitro studies have demonstrated that acute increases in pressure on the endothelium can lead to monocyte adhesion, an upregulation of adhesion molecules and inflammatory markers6 however, similar to many in vitro assays, these findings have not been performed in real time under physiological flow conditions, nor with whole blood. Therefore, in vivo assays are increasingly utilised in animal models to demonstrate vascular inflammation and plaque development. Intravital microscopy is now widely used to assess leukocyte adhesion, rolling, migration and transmigration7-9. When combining the effects of pressure on leukocyte to endothelial adhesion the in vivo studies are less extensive. One such study examines the real time effects of flow and shear on arterial growth and remodelling but inflammatory markers were only assessed via immunohistochemistry10. Here we present a model for recording leukocyte adhesion in real time in intact pressurised blood vessels using whole blood perfusion. The methodology is a modification of an ex vivo vessel chamber perfusion model9 which enables real-time analysis of leukocyte -endothelial adhesive interactions in intact vessels. Our modification enables the manipulation of the intraluminal pressure up to 200 mmHg allowing for study not only under physiological flow conditions but also pressure conditions. While pressure myography systems have been previously demonstrated to observe vessel wall and lumen diameter11 as well as vessel contraction this is the first time demonstrating leukocyte-endothelial interactions in real time. Here we demonstrate the technique using carotid arteries harvested from rats and cannulated to a custom-made flow chamber coupled to a fluorescent microscope. The vessel chamber is equipped with a large bottom coverglass allowing a large diameter objective lens with short working distance to image the vessel. Furthermore, selected agonist and/or antagonists can be utilized to further investigate the mechanisms controlling cell adhesion. Advantages of this method over intravital microscopy include no involvement of invasive surgery and therefore a higher throughput can be obtained. This method also enables the use of localised inhibitor treatment to the desired vessel whereas intravital only enables systemic inhibitor treatment.

This is a method to visualise leukocyte adhesion to the endothelium in harvested pressurised vessels. The technique enables studying vascular adhesion under shear flow with differing intraluminal pressures up to 200 mmHg thus mimic-ing the pathophysiological conditions of high blood pressure.

Imaging Leukozytenadhäsion an das vaskuläre Endothel bei hohen intraluminalen Druck

Worldwide, hypertension is reported to be in approximately a quarter of the population and is the leading biomedical risk factor for mortality worldwide. ...

Non-invasive Imaging of Disseminated Candidiasis in Zebrafish Larvae

Disseminated candidiasis caused by the pathogen Candida albicans is a clinically important problem in hospitalized individuals and is associated with a 30 to 40% attributable mortality6. Systemic candidiasis is normally controlled by innate immunity, and individuals with genetic defects in innate immune cell components such as phagocyte NADPH oxidase are more susceptible to candidemia7-9. Very little is known about the dynamics of C. albicans interaction with innate immune cells in vivo. Extensive in vitro studies have established that outside of the host C. albicans germinates inside of macrophages, and is quickly destroyed by neutrophils10-14. In vitro studies, though useful, cannot recapitulate the complex in vivo environment, which includes time-dependent dynamics of cytokine levels, extracellular matrix attachments, and intercellular contacts10, 15-18. To probe the contribution of these factors in host-pathogen interaction, it is critical to find a model organism to visualize these aspects of infection non-invasively in a live intact host. 
The zebrafish larva offers a unique and versatile vertebrate host for the study of infection. For the first 30 days of development zebrafish larvae have only innate immune defenses2, 19-21, simplifying the study of diseases such as disseminated candidiasis that are highly dependent on innate immunity. The small size and transparency of zebrafish larvae enable imaging of infection dynamics at the cellular level for both host and pathogen. Transgenic larvae with fluorescing innate immune cells can be used to identify specific cells types involved in infection22-24. Modified anti-sense oligonucleotides (Morpholinos) can be used to knock down various immune components such as phagocyte NADPH oxidase and study the changes in response to fungal infection5. In addition to the ethical and practical advantages of using a small lower vertebrate, the zebrafish larvae offers the unique possibility to image the pitched battle between pathogen and host both intravitally and in color. 
The zebrafish has been used to model infection for a number of human pathogenic bacteria, and has been instrumental in major advances in our understanding of mycobacterial infection3, 25. However, only recently have much larger pathogens such as fungi been used to infect larva5, 23, 26, and to date there has not been a detailed visual description of the infection methodology. Here we present our techniques for hindbrain ventricle microinjection of prim25 zebrafish, including our modifications to previous protocols. Our findings using the larval zebrafish model for fungal infection diverge from in vitro studies and reinforce the need to examine the host-pathogen interaction in the complex environment of the host rather than the simplified system of the Petri dish5.

The rapid development, small size and transparency of zebrafish are tremendous advantages for the study of innate immune control of infection1-4. Here we demonstrate techniques for infecting zebrafish larvae using the fungal pathogen Candida albicans by microinjection, methodology recently used to implicate phagocyte NADPH oxidase activity in control of fungal dimorphism5.

Nicht-invasive Bildgebung von disseminierter Candidiasis in Zebrafischlarven

Disseminated candidiasis caused by the pathogen Candida albicans is a clinically important problem in hospitalized individuals and is associated with a 30 ...

Bioluminescent Bacterial Imaging In Vivo

This video describes the use of whole body bioluminesce imaging (BLI) for the study of bacterial trafficking in live mice, with an emphasis on the use of bacteria in gene and cell therapy for cancer. Bacteria present an attractive class of vector for cancer therapy, possessing a natural ability to grow preferentially within tumors following systemic administration. Bacteria engineered to express the lux gene cassette permit BLI detection of the bacteria and concurrently tumor sites. The location and levels of bacteria within tumors over time can be readily examined, visualized in two or three dimensions. The method is applicable to a wide range of bacterial species and tumor xenograft types. This article describes the protocol for analysis of bioluminescent bacteria within subcutaneous tumor bearing mice. Visualization of commensal bacteria in the Gastrointestinal tract (GIT) by BLI is also described. This powerful, and cheap, real-time imaging strategy represents an ideal method for the study of bacteria in vivo in the context of cancer research, in particular gene therapy, and infectious disease. This video outlines the procedure for studying lux-tagged E. coli in live mice, demonstrating the spatial and temporal readout achievable utilizing BLI with the IVIS system.

Bioluminescent Bacterial Imaging In Vivo

This article describes the administration of lux-tagged bacteria to mice and subsequent in vivo analysis using IVIS bioluminescence imaging.

Bioluminescent Bakterielle Imaging<em&gt; In Vivo</em

This video describes the use of whole body bioluminesce imaging (BLI) for the study of bacterial trafficking in live mice, with an emphasis on the use of ...

Non-invasive Optical Imaging of the Lymphatic Vasculature of a Mouse

The lymphatic vascular system is an important component of the circulatory system that maintains fluid homeostasis, provides immune surveillance, and mediates fat absorption in the gut. Yet despite its critical function, there is comparatively little understanding of how the lymphatic system adapts to serve these functions in health and disease1. Recently, we have demonstrated the ability to dynamically image lymphatic architecture and lymph "pumping" action in normal human subjects as well as in persons suffering lymphatic dysfunction using trace administration of a near-infrared fluorescent (NIRF) dye and a custom, Gen III-intensified imaging system2-4. NIRF imaging showed dramatic changes in lymphatic architecture and function with human disease. It remains unclear how these changes occur and new animal models are being developed to elucidate their genetic and molecular basis. In this protocol, we present NIRF lymphatic, small animal imaging5,6 using indocyanine green (ICG), a dye that has been used for 50 years in humans7, and a NIRF dye-labeled cyclic albumin binding domain (cABD-IRDye800) peptide that preferentially binds mouse and human albumin8. Approximately 5.5 times brighter than ICG, cABD-IRDye800 has a similar lymphatic clearance profile and can be injected in smaller doses than ICG to achieve sufficient NIRF signals for imaging8. Because both cABD-IRDye800 and ICG bind to albumin in the interstitial space8, they both may depict active protein transport into and within the lymphatics. Intradermal (ID) injections (5-50 &mu;l) of ICG (645 &mu;M) or cABD-IRDye800 (200 &mu;M) in saline are administered to the dorsal aspect of each hind paw and/or the left and right side of the base of the tail of an isoflurane-anesthetized mouse. The resulting dye concentration in the animal is 83-1,250 &mu;g/kg for ICG or 113-1,700 &mu;g/kg for cABD-IRDye800. Immediately following injections, functional lymphatic imaging is conducted for up to 1 hr using a customized, small animal NIRF imaging system. Whole animal spatial resolution can depict fluorescent lymphatic vessels of 100 microns or less, and images of structures up to 3 cm in depth can be acquired9. Images are acquired using V++ software and analyzed using ImageJ or MATLAB software. During analysis, consecutive regions of interest (ROIs) encompassing the entire vessel diameter are drawn along a given lymph vessel. The dimensions for each ROI are kept constant for a given vessel and NIRF intensity is measured for each ROI to quantitatively assess "packets" of lymph moving through vessels.

Recently developed imaging techniques using near-infrared fluorescence (NIRF) may help elucidate the role the lymphatic system plays in cancer metastasis, immune response, wound repair, and other lymphatic-associated diseases.

Nicht-invasive optische Abbildung des lymphatischen Gefäßsystem eines Maus

The lymphatic  vascular system is an important component of the circulatory system that  maintains fluid homeostasis, provides immune surveillance, and ...

Non-Invasive Model of Neuropathogenic Escherichia coli Infection in the Neonatal Rat

Investigation of the interactions between animal host and bacterial pathogen is only meaningful if the infection model employed replicates the principal features of the natural infection. This protocol describes procedures for the establishment and evaluation of systemic infection due to neuropathogenic Escherichia coli K1 in the neonatal rat. Colonization of the gastrointestinal tract leads to dissemination of the pathogen along the gut-lymph-blood-brain course of infection and the model displays strong age dependency. A strain of E. coli O18:K1 with enhanced virulence for the neonatal rat produces exceptionally high rates of colonization, translocation to the blood compartment and invasion of the meninges following transit through the choroid plexus. As in the human host, penetration of the central nervous system is accompanied by local inflammation and an invariably lethal outcome. The model is of proven utility for studies of the mechanism of pathogenesis, for evaluation of therapeutic interventions and for assessment of bacterial virulence.

Non-Invasive Model of Neuropathogenic Escherichia coli Infection in the Neonatal Rat

Here, a procedure is described for the establishment of systemic infection in the neonatal rat with cultures of Escherichia coli K1. This non-invasive procedure permits colonization of the gastrointestinal tract, translocation of the pathogen to the systemic circulation, and invasion of the central nervous system at the choroid plexus.

Nichtinvasive Modell Neuropathogenic<em&gt; Escherichia coli</em&gt; Infektion in der neonatalen Ratten

Investigation of the interactions between animal host and bacterial pathogen is only meaningful if the infection model employed replicates the principal ...

Complete Thymectomy in Adult Rats with Non-invasive Endotracheal Intubation

Thymectomy in neonatal rodents is an established and reliable procedure for immunological studies. However, in adult rats, complications of hemorrhage and pneumothorax from pleural disruption can result in a significant mortality rate. This protocol is a simple method of rat thymectomy that utilizes a mini-sternotomy and endotracheal intubation. Intubation is accomplished with a non-invasive and easily reproducible method and allows for positive pressure ventilation to prevent pneumothorax and a controlled airway that allows sufficient time for careful thymus dissection to minimize pleural disruption. A 1.5 cm sternal incision decreases contact with mediastinal vessels and pleura, while still providing full visualization of the thymus. Following exposure of the mediastinum, the thymus is removed by blunt dissection under magnification. The pleural space is then sealed by suture closure of the pre-tracheal muscles followed by the application of surgical glue. The thorax is then closed by suture closure of the sternum, followed by suture closure of the skin. All thymectomies were complete as evidenced by immunohistochemical (IHC) staining of mediastinal tissue, and absence of na&#239;ve T-cells by flow cytometry, and the procedure had a 96% survival rate. This method is suitable when complete thymectomy with minimal complications is desired for further immunological studies in athymic adult rats.

Rodent thymectomy is a valuable technique in immunological research. Here, a protocol for complete thymectomy in adult rats using a mini-sternotomy along with non-invasive intubation and positive pressure ventilation to minimize perioperative morbidity and mortality is described.

Komplette Thymektomie bei erwachsenen Ratten mit Nicht-invasive Intubation

Thymectomy in neonatal rodents is an established and reliable procedure for immunological studies. However, in adult rats, complications of hemorrhage and ...

Non-invasive Imaging of the Innate Immune Response in a Zebrafish Larval Model of Streptococcus iniae Infection

The aquatic pathogen, Streptococcus iniae, is responsible for over 100 million dollars in annual losses for the aquaculture industry and is capable of causing systemic disease in both fish and humans. A better understanding of S. iniae disease pathogenesis requires an appropriate model system. The genetic tractability and the optical transparency of the early developmental stages of zebrafish allow for the generation and non-invasive imaging of transgenic lines with fluorescently tagged immune cells. The adaptive immune system is not fully functional until several weeks post fertilization, but zebrafish larvae have a conserved vertebrate innate immune system with both neutrophils and macrophages. Thus, the generation of a larval infection model allows the study of the specific contribution of innate immunity in controlling S. iniae infection.
The site of microinjection will determine whether an infection is systemic or initially localized. Here, we present our protocols for otic vesicle injection of zebrafish aged 2-3 days post fertilization as well as our techniques for fluorescent confocal imaging of infection. A localized infection site allows observation of initial microbe invasion, recruitment of host cells and dissemination of infection. Our findings using the zebrafish larval model of S. iniae infection indicate that zebrafish can be used to examine the differing contributions of host neutrophils and macrophages in localized bacterial infections. In addition, we describe how photolabeling of immune cells can be used to track individual host cell fate during the course of infection.

Non-invasive Imaging of the Innate Immune Response in a Zebrafish Larval Model of Streptococcus iniae Infection

Here, we present a protocol for the generation and imaging of a localized bacterial infection in the zebrafish otic vesicle.

Nicht-invasive Bildgebung von der angeborenen Immunantwort in einem Zebrafisch-Larven Modell<em&gt; Streptococcus iniae</em&gt; Infektions

The aquatic pathogen, Streptococcus iniae, is responsible for over 100 million dollars in annual losses for the aquaculture industry and is capable of ...

Intravital Microscopy of Leukocyte-endothelial and Platelet-leukocyte Interactions in Mesenterial Veins in Mice

Intravital microscopy is a method that can be used to investigate different processes in different regions and vessels in living animals. In this protocol, we describe intravital microscopy of mesentery veins. This can be performed in a short period of time with reproducible results showing leukocyte-endothelial interactions in vivo. We describe an inflammatory setting after LPS challenge of the endothelium. But in this model one can apply many different types of inflammatory conditions, like bacterial, chemical or biological and investigate the administration of drugs and their direct effects on the living animal and its impact on leukocyte recruitment. This protocol has been applied successfully to a number of different treatments of mice and their effects on inflammatory response in vessels. Herein, we describe the visualization of leukocytes and platelets by fluorescently labeling these with rhodamine 6G. Additionally, any specific imaging can be performed using targeted fluorescently labeled molecules.

This simplified application of intravital microscopy of mesentery veins in mice can be used in different models of inflammation to observe leukocyte-endothelial and platelet-leukocyte interactions.

Intravitalmikroskopie der Leukozyten-Endothel und Plättchen-Leukozyten-Wechselwirkungen in Mesenterialvenen in Mice

Intravital microscopy is a method that can be used to investigate different processes in different regions and vessels in living animals. In this ...

Imaging CD4 T Cell Interstitial Migration in the Inflamed Dermis

The ability of CD4 T cells to carry out effector functions is dependent upon the rapid and efficient migration of these cells in inflamed peripheral tissues through an as-yet undefined mechanism. The application of multiphoton microscopy to the study of the immune system provides a tool to measure the dynamics of immune responses within intact tissues. Here we present a protocol for non-invasive intravital multiphoton imaging of CD4 T cells in the inflamed mouse ear dermis. Use of a custom imaging platform and a venous catheter allows for the visualization of CD4 T cell dynamics in the dermal interstitium, with the ability to interrogate these cells in real-time via the addition of blocking antibodies to key molecular components involved in motility. This system provides advantages over both in vitro models and surgically invasive imaging procedures. Understanding the pathways used by CD4 T cells for motility may ultimately provide insight into the basic function of CD4 T cells as well as the pathogenesis of both autoimmune diseases and pathology from chronic infections.

The mechanisms that govern the interstitial motility of CD4 effector T cells at sites of inflammation are relatively unknown. We present a non-invasive approach to visualize and manipulate in vitro-primed CD4 T cells in the inflamed ear dermis, allowing for study of the dynamic behavior of these cells in situ.

Imaging CD4 T-Zell-Interstitial Migration in den entzündeten Dermis

The ability of CD4 T cells to carry out effector functions is dependent upon the rapid and efficient migration of these cells in inflamed peripheral ...