Les auteurs tiennent à remercier les membres du laboratoire pour les soins de poisson zèbre et la maintenance. Ce travail a été soutenu par les National Institutes of Health, National Service Award recherche A155397 à EA Harvie et NIH R01GM074827 à Anna Huttenlocher.

<ol>
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L., 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=Infection+of+Zebrafish+Embryos+with+Intracellular+Bacterial+Pathogens.">Infection of Zebrafish Embryos with Intracellular Bacterial Pathogens.</a> J. Vis. Exp. , 1-9 (2012).</li><li>Carvalho, 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=A+High-Throughput+Screen+for+Tuberculosis+Progression.">A High-Throughput Screen for Tuberculosis Progression.</a> PLoS ONE. 6 (2), e16779 (2011).</li><li>Veneman, W. J., Mar&#237;n-Juez, 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=Establishment+and+Optimization+of+a+High+Throughput+Setup+to+Study+Staphylococcus+epidermidis+and+Mycobacterium+marinum+Infection+as+a+Model+for+Drug+Discovery.">Establishment and Optimization of a High Throughput Setup to Study Staphylococcus epidermidis and Mycobacterium marinum Infection as a Model for Drug Discovery.</a> J. Vis. Exp. (88), (2014).</li><li>Deng, Q., Harvie, E. A., Huttenlocher, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distinct+signaling+mechanisms+mediate+neutrophil+attraction+to+bacterial+infection+and+tissue+injury.">Distinct signaling mechanisms mediate neutrophil attraction to bacterial infection and tissue injury.</a> Cell. Microbiol. , (2012).</li><li>Sar, A. 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=Zebrafish+embryos+as+a+model+host+for+the+real+time+analysis+of+Salmonella+typhimurium+infections.">Zebrafish embryos as a model host for the real time analysis of Salmonella typhimurium infections.</a> Cell. Microbiol. 5 (9), 601-611 (2003).</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.">Streptolysin S Inhibits Neutrophil Recruitment during the Early Stages of Streptococcus pyogenes Infection.</a> Infect. Immun. 77 (11), 5190-5201 (2009).</li><li>Volhard, C., Dahm, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Zebrafish: A Practical Approach. , (2002).</li><li>He, S., 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=Neutrophil-mediated+experimental+metastasis+is+enhanced+by+VEGFR+inhibition+in+a+zebrafish+xenograft+model.">Neutrophil-mediated experimental metastasis is enhanced by VEGFR inhibition in a zebrafish xenograft model.</a> J. Pathol. 227 (4), 431-445 (2012).</li><li>Haldi, M., Ton, C., Seng, W. L., McGrath, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+melanoma+cells+transplanted+into+zebrafish+proliferate,+migrate,+produce+melanin,+form+masses+and+stimulate+angiogenesis+in+zebrafish.">Human melanoma cells transplanted into zebrafish proliferate, migrate, produce melanin, form masses and stimulate angiogenesis in zebrafish.</a> Angiogenesis. 9 (9), 139-151 (2006).</li><li>Davis, J. 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=Real-time+visualization+of+mycobacterium-macrophage+interactions+leading+to+initiation+of+granuloma+formation+in+zebrafish+embryos.">Real-time visualization of mycobacterium-macrophage interactions leading to initiation of granuloma formation in zebrafish embryos.</a> Immunity. 17 (6), 693-702 (2002).</li><li>Wiles, T. J., Bower, J. M., Redd, M. J., Mulvey, 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=Use+of+Zebrafish+to+Probe+the+Divergent+Virulence+Potentials+and+Toxin+Requirements+of+Extraintestinal+Pathogenic+Escherichia+coli.">Use of Zebrafish to Probe the Divergent Virulence Potentials and Toxin Requirements of Extraintestinal Pathogenic Escherichia coli.</a> PLoS Pathog. 5 (12), e1000697 (2009).</li><li>Harvie, E. A., Green, J. M., Neely, M. N., Huttenlocher, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Innate+Immune+Response+to+Streptococcus+iniae+Infection+in+Zebrafish+Larvae.">Innate Immune Response to Streptococcus iniae Infection in Zebrafish Larvae.</a> Infect. Immun. 81 (1), 110-121 (2013).</li><li>Haddon, C., Lewis, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+Ear+Development+in+the+Embryo+of+the+Zebrafish,+Danio+rerio.">Early Ear Development in the Embryo of the Zebrafish, Danio rerio.</a> J. Comp. Neurol. 365, 113-128 (1996).</li><li>Whitfield, T. T., Riley, B. B., Chiang, M. -. Y., Phillips, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+the+zebrafish+inner+ear.">Development of the zebrafish inner ear.</a> Dev. Dyn. 223 (4), 427-458 (2002).</li><li>Rosen, J. N., Sweeney, M. F., Mably, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microinjection+of+zebrafish+embryos+to+analyze+gene+function.">Microinjection of zebrafish embryos to analyze gene function.</a> J. Vis. Exp. (25), (2009).</li><li>Colucci-Guyon, E., Tinevez, J. Y., Renshaw, S. A., Herbomel, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strategies+of+professional+phagocytes+in+vivo:+unlike+macrophages,+neutrophils+engulf+only+surface-associated+microbes.">Strategies of professional phagocytes in vivo: unlike macrophages, neutrophils engulf only surface-associated microbes.</a> J. Cell Sci. 124 (18), 3053-3059 (2011).</li><li>Gurskaya, N. 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The authors declare that they have no competing financial interests.

La méthode d&#39;infection utilisé ici est utile pour l&#39;étude de la réponse immunitaire de l&#39;hôte à une infection localisée initialement dans 2 à 3 dpf embryons et les larves. La mise au point d&#39;un stimulus inflammatoire, comme une infection, dans une cavité fermée de telle sorte que la vésicule otique permet l&#39;étude de la chimiotaxie de neutrophiles et de macrophages et de phagocytose. Une mise en garde de l&#39;injection de bactéries dans la vésicule otique est que la capacité des neutro...

Streptococcus iniae est un agent pathogène aquatique majeur qui est capable de provoquer une maladie systémique dans les poissons et les humains 1. Bien que S. iniae est responsable de pertes importantes dans l&#39;industrie de l&#39;aquaculture, ce est aussi un agent pathogène zoonotique potentiel, capable de provoquer une maladie chez les hôtes humains immunodéprimés atteints de pathologies cliniques similaires à ceux causés par d&#39;autres agents pathogènes humains streptocoques. Compte tenu de ses similitudes avec des agents pathogènes humains, il est important d&#39;étudier S. iniae pathogenèse des maladies dans le contexte d&#39;un hôte naturel. Un modèle de poisson zèbre adulte de S. infection iniae a révélé l&#39;infiltration robuste de leucocytes d&#39;accueil sur le site de l&#39;infection localisée ainsi comme un temps rapide d&#39;accueillir la mort, un temps trop court pour impliquer le système immunitaire adaptatif 7. Afin d&#39;obtenir un regard en profondeur dans la réponse immunitaire innée à S. iniae infection in vivo, il est nécessaire d&#39;utiliser un modèle qui est plus favorable à nsur-invasive imagerie en temps réel. Le poisson zèbre larves a un certain nombre d&#39;avantages qui en font un modèle vertébré plus en plus attrayant pour étudier les interactions hôte-pathogène. Poisson zèbre sont relativement peu coûteux et facile à utiliser et à entretenir par rapport aux modèles de mammifères. L&#39;immunité adaptative est pas fonctionnellement matures jusqu&#39;à 4-6 semaines après la fécondation, mais les larves ont un système immunitaire inné des vertébrés hautement conservée avec le complément, Toll-like récepteurs, les cytokines et les neutrophiles et les macrophages avec des capacités antimicrobiennes y compris la phagocytose et la bouffée respiratoire 2-6, 8-11. En outre, la traçabilité génétique et la transparence optique des stades embryonnaires et larvaires de développement pour permettre la génération de lignées transgéniques stables avec les cellules immunitaires marquées par fluorescence permettant d&#39;étudier les interactions hôte-pathogène en temps réel in vivo. La génération de ces lignées transgéniques en utilisant une protéine photoconvertible tels que DenDRA2 permet le suivi de l&#39;origine de la cellule hôte et le destin individuel au cours de l&#39;infection 12. Lors de l&#39;élaboration d&#39;un modèle d&#39;infection des larves de poisson zèbre, le site choisi de microinjection permettra de déterminer si une infection est initialement localisée ou systémique. Infections du sang systémique dans la veine caudale ou un conduit de Cuvier sont les plus couramment utilisées pour étudier les pathogènes microbiens chez le poisson zèbre et sont utiles pour étudier les interactions entre l&#39;hôte et des cellules microbiennes, les réponses de cytokines, et les différences de virulence entre les souches pathogènes. Pour les micro-organismes à croissance plus lente, une injection précoce dans le sac vitellin d&#39;un embryon au stade 16-1,000 cellulaire peut être utilisée pour générer une infection systémique 13,14, avec le stade de développement optimal pour la micro-injection d&#39;un micro-organisme à croissance lente jugée entre l&#39;étape 16 à 128 de la cellule 15. Toutefois, le jaune injections sac de nombreux microbes à des stades ultérieurs de développement hôte ont tendance à être mortelle à til accueillera en raison de l&#39;environnement riche en nutriments pour le microbe et le manque de leucocytes infiltrants 16-18. Une infection localisée se traduit généralement par la migration dirigée des leucocytes vers le site de l&#39;infection qui peut être facilement quantifiée par imagerie non invasive. Ce type d&#39;infection peut permettre pour la dissection des mécanismes qui interviennent dans la migration des leucocytes ainsi que des enquêtes de différentes capacités migratoires et phagocytaires de diverses populations leucocytaires. Infections localisées sont également utiles lors de l&#39;examen des différences de virulence entre les souches bactériennes ainsi que l&#39;étude des mécanismes d&#39;invasion de microbes depuis barrières de l&#39;hôte physiques doivent être croisés pour une infection localisée à devenir systémique. Poisson zèbre sont généralement soulevé à des températures de 25-31 ° C 19, mais ils peuvent aussi être maintenu à des températures aussi élevées que 34 à 35 ° C pour les études de l&#39;envahissement de certains agents pathogènes humains avec les exigences de température strictespour la virulence 20, 21. De nombreux sites différents ont été utilisés pour générer une infection bactérienne localisée initialement compris le ventricule du cerveau postérieur 22, queue muscle dorsal 18, la cavité péricardique 23, et la vésicule otique (oreille) 5, 16, 24. Cependant, il a été trouvé que l&#39;injection des bactéries en queue muscle peut causer des dommages aux tissus et l&#39;inflammation indépendante des bactéries, ce qui peut fausser les résultats lorsque l&#39;enquête réponse des leucocytes 13. Bien que moins de dommages est associé à l&#39;injection dans le cerveau postérieur et bien que ce est d&#39;abord dépourvu de leucocytes chez les jeunes embryons, le ventricule rhombencéphale gagne progressivement les cellules immunitaires dans le temps que les microglies se installent. Le ventricule rhombencéphale est également un endroit plus difficile à l&#39;image. La vésicule otique est une cavité creuse fermée sans accès direct à la vascularisation 25, 26. Il est normalement dépourvue de leukocytes leucocytes, mais peuvent être recrutés pour la vésicule otique en réponse à des stimuli inflammatoires telles que l&#39;infection. Il est également un site privilégié de la micro-injection de bactéries chez le poisson zèbre ans après la fécondation (DPF) 2-3 jours en raison de la facilité d&#39;imagerie et la visualisation de l&#39;injection. Par conséquent, nous avons choisi la vésicule otique que notre site d&#39;infection bactérienne localisée.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>1.7 ml eppendorfs</td>
			<td>MidSci</td>
			<td>AVSS1700</td>
			<td></td>
		</tr>
		<tr>
			<td>14 ml falcon tube</td>
			<td>BD Falcon</td>
			<td>352059</td>
			<td></td>
		</tr>
		<tr>
			<td>27 G x 1/2 in. needle</td>
			<td>BD Biosciences</td>
			<td>305109</td>
			<td></td>
		</tr>
		<tr>
			<td>96 well plate</td>
			<td>Corning Incorporated</td>
			<td>3596</td>
			<td></td>
		</tr>
		<tr>
			<td>Agar</td>
			<td>BD Biosciences</td>
			<td>214030</td>
			<td></td>
		</tr>
		<tr>
			<td>CellTracker Red</td>
			<td>Molecular Probes, Invitrogen</td>
			<td>C34552</td>
			<td></td>
		</tr>
		<tr>
			<td>CNA agar</td>
			<td>Dot Scientific, Inc</td>
			<td>7126A</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable transfer pipets</td>
			<td>Fisher Scientific</td>
			<td>13-711-7m</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting Scope</td>
			<td>Nikon</td>
			<td>SMZ745</td>
			<td></td>
		</tr>
		<tr>
			<td>DMSO</td>
			<td>Sigma Aldrich</td>
			<td>D2650</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol 200 proof</td>
			<td>MDS</td>
			<td>2292</td>
			<td></td>
		</tr>
		<tr>
			<td>Fine tweezers</td>
			<td>Fine Science Tools</td>
			<td>11251-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Gel comb</td>
			<td>VWR</td>
			<td>27372-482</td>
			<td>4.2 mm width, 1.5 mm thick</td>
		</tr>
		<tr>
			<td>Glass bottom dishes</td>
			<td></td>
			<td></td>
			<td>Custom made by drilling a 16&#8211;18 mm hole in the center of a 35-mm tissue culture dish bottom and placing a 22-mm round #1 coverslip in the hole and sealing with a thin layer of Norland Optical Adhesive 68 cured by UV light.</td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>Fisher Scientific</td>
			<td>G33-4</td>
			<td></td>
		</tr>
		<tr>
			<td>High melt agarose</td>
			<td>Denville Scientific, Inc.</td>
			<td>CA3510-6</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrogen peroxide</td>
			<td>Fisher Scientific</td>
			<td>H325</td>
			<td></td>
		</tr>
		<tr>
			<td>Laser Scanning Confocal Microscope</td>
			<td>Olympus</td>
			<td>with FV-1000 system</td>
			<td></td>
		</tr>
		<tr>
			<td>Low melt agarose</td>
			<td>Fisher</td>
			<td>BP165-25</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic stand</td>
			<td>Tritech (Narishige)</td>
			<td>GJ-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Microinjection system</td>
			<td>Parker</td>
			<td>Picospritzer III</td>
			<td></td>
		</tr>
		<tr>
			<td>Microloader pipet tips</td>
			<td>Eppendorf</td>
			<td>930001007</td>
			<td></td>
		</tr>
		<tr>
			<td>Micromanipulator</td>
			<td>Tritech (Narishige)</td>
			<td>M-152</td>
			<td></td>
		</tr>
		<tr>
			<td>Micropipette puller</td>
			<td>Sutter Instrument Company</td>
			<td>Flaming/Brown P-97</td>
			<td></td>
		</tr>
		<tr>
			<td>Nanodrop spectrophotmeter</td>
			<td>Thermo Scientific</td>
			<td>ND-1000</td>
			<td></td>
		</tr>
		<tr>
			<td>N-Phenylthiourea (PTU)</td>
			<td>Sigma aldrich</td>
			<td>P7629</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldheyde</td>
			<td>Electron Microscopy Sciences</td>
			<td>15710</td>
			<td></td>
		</tr>
		<tr>
			<td>Petri Dishes</td>
			<td>Fisher Scientific</td>
			<td>FB0875712</td>
			<td>100 mm x 15 mm</td>
		</tr>
		<tr>
			<td>Phenol</td>
			<td>Sigma Aldrich</td>
			<td>P-4557</td>
			<td></td>
		</tr>
		<tr>
			<td>Phenol Red</td>
			<td>Ricca Chemoical Company</td>
			<td>572516</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate Buffered Saline</td>
			<td>Fisher Scientific</td>
			<td>BP665-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium hydroxide</td>
			<td>Sigma Aldrich</td>
			<td>P-6310</td>
			<td></td>
		</tr>
		<tr>
			<td>Pronase</td>
			<td>Roche</td>
			<td>165921</td>
			<td></td>
		</tr>
		<tr>
			<td>Protease peptone</td>
			<td>Fluka Biochemika</td>
			<td>29185</td>
			<td></td>
		</tr>
		<tr>
			<td>Small cell culture dish</td>
			<td>Corning Incorporated</td>
			<td>430165</td>
			<td>35 mm x 10 mm</td>
		</tr>
		<tr>
			<td>Sudan Black</td>
			<td>Sigma Aldrich</td>
			<td>S2380</td>
			<td></td>
		</tr>
		<tr>
			<td>Thin wall glass capillary injection needles</td>
			<td>World Precision Instruments, Inc.</td>
			<td>TW100-3</td>
			<td></td>
		</tr>
		<tr>
			<td>Todd Hewitt</td>
			<td>Sigma Aldrich/Fluka Analytical</td>
			<td>T1438</td>
			<td></td>
		</tr>
		<tr>
			<td>Tricaine (ethyl 3-aminobenzoate)</td>
			<td>Argent Chemical Laboratory/Finquel</td>
			<td>C-FINQ-UE-100G</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Fisher Scientific</td>
			<td>BP151-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Tween 20</td>
			<td>Fisher Scientific</td>
			<td>BP337-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Yeast extract</td>
			<td>Fluka Biochemika</td>
			<td>92144</td>
			<td></td>
		</tr>
	</tbody>
</table>

non-invasive imaging of the innate immune response in a zebrafish larval model of streptococcus iniae infection

L&#39;agent pathogène aquatique, Streptococcus iniae, est responsable de plus de 100 millions de dollars de pertes annuelles pour l&#39;industrie de l&#39;aquaculture et est capable de provoquer une maladie systémique dans les deux poissons et les humains. Une meilleure compréhension de S. maladie iniae pathogénie nécessite un système de modèle approprié. La traçabilité génétique et la transparence optique des premiers stades de développement du poisson zèbre pour permettre la génération et l&#39;imagerie non-invasive de lignées transgéniques avec étiqueté par fluorescence des cellules immunitaires. Le système immunitaire adaptatif est pas complètement fonctionnel jusqu&#39;à plusieurs semaines après la fécondation, mais larves de poisson zèbre ont un système immunitaire inné de vertébré conservé à la fois les neutrophiles et les macrophages. Ainsi, la génération d&#39;un modèle d&#39;infection larvaire permet l&#39;étude de la contribution spécifique de l&#39;immunité innée dans le contrôle de S. infection iniae. Le site de micro-injection permettra de déterminer si une infection estsystémique ou localisée initialement. Ici, nous présentons nos protocoles pour l&#39;injection de vésicule otique du poisson zèbre âgés de 2-3 jours après la fécondation ainsi que nos techniques d&#39;imagerie confocale de fluorescence de l&#39;infection. Un site d&#39;infection localisée permet l&#39;observation de l&#39;invasion microbienne initiale, recrutement des cellules hôtes et la diffusion de l&#39;infection. Nos résultats en utilisant le modèle des larves de poisson zèbre de S. iniae infection indiquent que le poisson zèbre peut être utilisé pour examiner les différents apports de neutrophiles et les macrophages d&#39;accueil dans les infections bactériennes localisées. En outre, nous décrivons comment photomarquage des cellules immunitaires peut être utilisé pour suivre le destin des cellules hôte individuel au cours de l&#39;infection.

Microinjection de S. iniae dans la vésicule otique (Figure 1 et Figure 2) conduit à une réponse de l&#39;hôte initialement localisée. Lorsqu&#39;elle est injectée correctement, les bactéries doivent seulement être vu dans la vésicule otique et non dans le tissu ou le sang environnant. Ceci peut être visualisé au cours de la micro-injection en utilisant un colorant rouge de phénol (figure 1A). Alternativement, si bactéries marquées sont injectées,...

Watch this Scientific Journal Video about Non-invasive Imaging of the Innate Immune Response in a Zebrafish Larval Model of Streptococcus iniae Infection at JoVE.com

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.

Imagerie non invasive de la réponse immunitaire innée dans un modèle de poisson zèbre larves de<em&gt; Streptococcus iniae</em&gt; Infection

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

non-invasive-imaging-innate-immune-response-zebrafish-larval-model

Research

JoVE Journal

Immunology and Infection

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

10.7K vues.  University of Wisconsin-Madison. Here, we present a protocol for the generation and imaging of a localized bacterial infection in the zebrafish otic vesicle. 

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

Non-invasive Imaging of Leukocyte Homing and Migration in vivo

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 provides rich spatiotemporal information regarding cell behaviors within intact tissues and in live mice. Leukocyte recruitment plays a significant role in host defense against infection and when unchecked, can contribute to inflammatory and autoimmune diseases. Studying leukocyte recruitment in vivo is technically challenging since cells are moving rapidly within vessels located deep within light scattering tissues. To date, most intravital imaging studies require surgical preparation to expose the blood vessels and tissues. To avoid the tissue damage and inflammation induced by surgery itself, here, we describe a non-invasive single-cell imaging approach that can be used to study leukocyte trafficking in the mouse footpad and phalanges. We discuss the technical aspects of our 2P imaging preparation and walk the reader through a typical experiment from initial set up to execution and data collection.

Non-invasive Imaging of Leukocyte Homing and Migration in vivo

Here, we describe a non-invasive two-photon (2P) microscopy approach to study leukocyte homing in the mouse footpad. We discuss the technical aspects of our tissue imaging preparation and walk the reader through a typical experiment from initial set up to execution and data collection.

L&#39;imagerie non invasive des Homing leucocytes et des migrations 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 ...

Recherche

Immunologie et infection

Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice

During the 1918 influenza virus pandemic, which killed approximately 50 million people worldwide, the majority of fatalities were not the result of infection with influenza virus alone. Instead, most individuals are thought to have succumbed to a secondary bacterial infection, predominately caused by the bacterium Streptococcus pneumoniae (the pneumococcus). The synergistic relationship between infections caused by influenza virus and the pneumococcus has subsequently been observed during the 1957 Asian influenza virus pandemic, as well as during seasonal outbreaks of the virus (reviewed in 1, 2). Here, we describe a protocol used to investigate the mechanism(s) that may be involved in increased morbidity as a result of concurrent influenza A virus and S. pneumoniae infection. We have developed an infant murine model to reliably and reproducibly demonstrate the effects of influenza virus infection of mice colonised with S. pneumoniae. Using this protocol, we have provided the first insight into the kinetics of pneumococcal transmission between co-housed, neonatal mice using in vivo imaging 3.

Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice

A concurrent infection with influenza A virus is one of the factors implicated in the induction of invasive pneumococcal disease during asymptomatic Streptococcus pneumoniae carriage. Here we describe a mixed infection method using infant mice to investigate the synergism between these two respiratory pathogens.

Utiliser l&#39;imagerie Bioluminescent chargé d&#39;enquêter sur une synergie entre Streptococcus pneumoniae Et virus Influenza A de souriceaux

During the 1918 influenza virus pandemic, which killed approximately 50 million people worldwide, the majority of fatalities were not the result of ...

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.

L&#39;imagerie non invasive de la candidose disséminée chez les larves poisson zèbre

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

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.

Non invasive d&#39;imagerie optique du système vasculaire lymphatique d&#39;une souris

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

Quantitative Measurement of the Immune Response and Sleep in Drosophila

A complex interaction between the immune response and host behavior has been described in a wide range of species. Excess sleep, in particular, is known to occur as a response to infection in mammals 1 and has also recently been described in Drosophila melanogaster2. It is generally accepted that sleep is beneficial to the host during an infection and that it is important for the maintenance of a robust immune system3,4. However, experimental evidence that supports this hypothesis is limited4, and the function of excess sleep during an immune response remains unclear. We have used a multidisciplinary approach to address this complex problem, and have conducted studies in the simple genetic model system, the fruitfly Drosophila melanogaster. We use a standard assay for measuring locomotor behavior and sleep in flies, and demonstrate how this assay is used to measure behavior in flies infected with a pathogenic strain of bacteria. This assay is also useful for monitoring the duration of survival in individual flies during an infection. Additional measures of immune function include the ability of flies to clear an infection and the activation of NF&kappa;B, a key transcription factor that is central to the innate immune response in Drosophila. Both survival outcome and bacterial clearance during infection together are indicators of resistance and tolerance to infection. Resistance refers to the ability of flies to clear an infection, while tolerance is defined as the ability of the host to limit damage from an infection and thereby survive despite high levels of pathogen within the system5. Real-time monitoring of NF&kappa;B activity during infection provides insight into a molecular mechanism of survival during infection. The use of Drosophila in these straightforward assays facilitates the genetic and molecular analyses of sleep and the immune response and how these two complex systems are reciprocally influenced.

Quantitative Measurement of the Immune Response and Sleep in Drosophila

To understand a link between the immune response and behavior, we describe a method to measure locomotor behavior in Drosophila during bacterial infection as well as the ability of flies to mount an immune response by monitoring survival, bacterial load, and real-time activity of a key regulator of innate immunity, NF&kappa;B.

Mesure quantitative de la réponse immunitaire et le sommeil en<em&gt; Drosophila</em

A complex interaction between the immune response and  host behavior has been described in a wide range of species. Excess sleep, in  particular, is known ...

Quantification of the Respiratory Burst Response as an Indicator of Innate Immune Health in Zebrafish

The phagocyte respiratory burst is part of the innate immune response to pathogen infection and involves the production of reactive oxygen species (ROS). ROS are toxic and function to kill phagocytized microorganisms. In vivo quantification of phagocyte-derived ROS provides information regarding an organism's ability to mount a robust innate immune response. Here we describe a protocol to quantify and compare ROS in whole zebrafish embryos upon chemical induction of the phagocyte respiratory burst. This method makes use of a non-fluorescent compound that becomes fluorescent upon oxidation by ROS. Individual zebrafish embryos are pipetted into the wells of a microplate and incubated in this fluorogenic substrate with or without a chemical inducer of the respiratory burst. Fluorescence in each well is quantified at desired time points using a microplate reader. Fluorescence readings are adjusted to eliminate background fluorescence and then compared using an unpaired t-test. This method allows for comparison of the respiratory burst potential of zebrafish embryos at different developmental stages and in response to experimental manipulations such as protein knockdown, overexpression, or treatment with pharmacological agents. This method can also be used to monitor the respiratory burst response in whole dissected kidneys or cell preparations from kidneys of adult zebrafish and some other fish species. We believe that the relative simplicity and adaptability of this protocol will complement existing protocols and will be of interest to researchers who seek to better understand the innate immune response.

The innate immune response protects organisms against pathogen infection. A critical component of the innate immune response, the phagocyte respiratory burst, generates reactive oxygen species that kill invading microorganisms. We describe a respiratory burst assay that quantifies reactive oxygen species produced when the innate immune response is chemically induced.

Quantification de la réponse du Rafale respiratoire comme indicateur d&#39;Innate Immune Health chez le poisson zèbre

The phagocyte respiratory burst is part of the innate immune response to  pathogen infection and involves the production of reactive oxygen species (ROS). ...

Dissecting Innate Immune Signaling in Viral Evasion of Cytokine Production

In response to a viral infection, the host innate immune response is activated to up-regulate gene expression and production of antiviral cytokines. Conversely, viruses have evolved intricate strategies to evade and exploit host immune signaling for survival and propagation. Viral immune evasion, entailing host defense and viral evasion, provides one of the most fascinating and dynamic interfaces to discern the host-virus interaction. These studies advance our understanding in innate immune regulation and pave our way to develop novel antiviral therapies.
Murine &#947;HV68 is a natural pathogen of murine rodents. &#947;HV68 infection of mice provides a tractable small animal model to examine the antiviral response to human KSHV and EBV of which perturbation of in vivo virus-host interactions is not applicable. Here we describe a protocol to determine the antiviral cytokine production. This protocol can be adapted to other viruses and signaling pathways.
Recently, we have discovered that &#947;HV68 hijacks MAVS and IKK&#946;, key innate immune signaling components downstream of the cytosolic RIG-I and MDA5, to abrogate NF&#922;B activation and antiviral cytokine production. Specifically, &#947;HV68 infection activates IKK&#946; and that activated IKK&#946; phosphorylates RelA to accelerate RelA degradation. As such, &#947;HV68 efficiently uncouples NF&#922;B activation from its upstream activated IKK&#946;, negating antiviral cytokine gene expression. This study elucidates an intricate strategy whereby the upstream innate immune activation is intercepted by a viral pathogen to nullify the immediate downstream transcriptional activation and evade antiviral cytokine production.

We describe a protocol to measure the antiviral cytokine production in mice infected with a model herpesvirus, murine gamma herpesvirus 68 (&#947;HV68) that is closely-related to human Kaposi&#8217;s sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV). Utilizing genetically modified mouse strains and mouse embryonic fibroblasts (MEFs), we assessed the antiviral cytokine production both in vivo and ex vivo. &#8220;Reconstituting&#8221; the expression of innate immune components in knockout embryonic fibroblasts by lentiviral transduction, we further pinpoint specific innate immune molecules and dissect the key signaling events that differentially regulate the antiviral cytokine production.

Dissection Innate Immune signalisation Evasion virale de la production de cytokines

In response to a viral infection, the host innate immune response is activated to up-regulate gene expression and production of antiviral cytokines. ...

Using RNA-interference to Investigate the Innate Immune Response in Mouse Macrophages

Macrophages are key phagocytic innate immune cells. When macrophages encounter a pathogen, they produce antimicrobial proteins and compounds to kill the pathogen, produce various cytokines and chemokines to recruit and stimulate other immune cells, and present antigens to stimulate the adaptive immune response. Thus, being able to efficiently manipulate macrophages with techniques such as RNA-interference (RNAi) is critical to our ability to investigate this important innate immune cell. However, macrophages can be technically challenging to transfect and can exhibit inefficient RNAi-induced gene knockdown. In this protocol, we describe methods to efficiently transfect two mouse macrophage cell lines (RAW264.7 and J774A.1) with siRNA using the Amaxa Nucleofector 96-well Shuttle System and describe procedures to maximize the effect of siRNA on gene knockdown. Moreover, the described methods are adapted to work in 96-well format, allowing for medium and high-throughput studies. To demonstrate the utility of this approach, we describe experiments that utilize RNAi to inhibit genes that regulate lipopolysaccharide (LPS)-induced cytokine production.

In this protocol, we describe methods to efficiently transfect murine macrophage cell lines with siRNAs using the Amaxa Nucleofector 96-well Shuttle System, stimulate the macrophages with lipopolysaccharide, and monitor the effects on inflammatory cytokine production.

En utilisant l&#39;ARN interférence pour étudier la réponse immunitaire innée dans les macrophages de souris

Macrophages are key phagocytic innate immune cells.  When macrophages encounter a pathogen, they produce antimicrobial proteins and compounds to kill the ...

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.

Modèle non-invasive de neuropathogènes<em&gt; Escherichia coli</em&gt; Maladies infectieuses chez le rat nouveau-né

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

In Vitro Analysis of Myd88-mediated Cellular Immune Response to West Nile Virus Mutant Strain Infection

An attenuated West Nile virus (WNV), a nonstructural (NS) 4B-P38G mutant, induced higher innate cytokine and T cell responses than the wild-type WNV in mice. Recently, myeloid differentiation factor 88 (MyD88) signaling was shown to be important for initial T cell priming and memory T cell development during WNV NS4B-P38G mutant infection. In this study, two flow cytometry-based methods &#8211; an in vitro T cell priming assay and an intracellular cytokine staining (ICS) &#8211; were utilized to assess dendritic cells (DCs) and T cell functions. In the T cell priming assay, cell proliferation was analyzed by flow cytometry following co-culture of DCs from both groups of mice with carboxyfluorescein succinimidyl ester (CFSE) - labeled CD4+ T cells of OTII transgenic mice. This approach provided an accurate determination of the percentage of proliferating CD4+ T cells with significantly improved overall sensitivity than the traditional assays with radioactive reagents. A microcentrifuge tube system was used in both cell culture and cytokine staining procedures of the ICS protocol. Compared to the traditional tissue culture plate-based system, this modified procedure was easier to perform at biosafety level (BL) 3 facilities. Moreover, WNV- infected cells were treated with paraformaldehyde in both assays, which enabled further analysis outside BL3 facilities. Overall, these in vitro immunological assays can be used to efficiently assess cell-mediated immune responses during WNV infection.

In Vitro Analysis of Myd88-mediated Cellular Immune Response to West Nile Virus Mutant Strain Infection

Two flow cytometry-based methods &#8211; an in vitro T cell priming assay and intracellular cytokine staining were utilized to measure antigen presenting capacity of dendritic cells and antigen-specific T cell responses to a West Nile virus mutant infection in mice.

Analyse in vitro de la réponse immunitaire cellulaire Myd88 médiation au virus du Nil occidental souche mutante Infection

An attenuated West Nile virus (WNV), a nonstructural (NS) 4B-P38G mutant, induced higher innate cytokine and T cell responses than the wild-type WNV in ...