Nous remercions les membres du Laboratoire de Biologie Phagosome pour la lecture critique du manuscrit. Ce travail est soutenu par une subvention de Helmholtz Young Investigator (Initiative et les fonds de mise en réseau de l&#39;Association Helmholtz) et un programme de priorité SPP1580 Grant du Conseil de recherches en allemand (Deutsche Forschungsgemeinschaft).

<ol>
	<li>Greenberg, S., Grinstein, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phagocytosis+and+innate+immunity.">Phagocytosis and innate immunity.</a> Curr. Opin. Immunol. 14, 136-145 (2002).</li><li>Jutras, I., Desjardins, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phagocytosis:+at+the+crossroads+of+innate+and+adaptive+immunity.">Phagocytosis: at the crossroads of innate and adaptive immunity.</a> Ann. Rev. Cell Dev. Biol. 21, 511-527 (2005).</li><li>Iwasaki, A., Medzhitov, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+adaptive+immunity+by+the+innate+immune+system.">Regulation of adaptive immunity by the innate immune system.</a> Science. 327, 291-295 (2010).</li><li>Stuart, L., Ezekowitz, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phagocytosis:+elegant+complexity.">Phagocytosis: elegant complexity.</a> Immunity. 22, 539-550 (2005).</li><li>Blander, J. M., Medzhitov, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+regulation+of+phagosome+maturation+and+antigen+presentation.">On regulation of phagosome maturation and antigen presentation.</a> Nat. Immunol. 7, 1029-1035 (2006).</li><li>Flannagan, R. S., Jaumouille, V., Grinstein, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+cell+biology+of+phagocytosis.">The cell biology of phagocytosis.</a> Annu. Rev. Pathol. 7, 61-98 (2012).</li><li>Vieira, O. V., Botelho, R. J., Grinstein, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phagosome+maturation:+aging+gracefully.">Phagosome maturation: aging gracefully.</a> Biochem. J. 366, 689-704 (2002).</li><li>Haas, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+phagosome:+compartment+with+a+license+to+kill.">The phagosome: compartment with a license to kill.</a> Traffic. 8, 311-330 (2007).</li><li>Flannagan, R. S., Cosio, G., Grinstein, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antimicrobial+mechanisms+of+phagocytes+and+bacterial+evasion+strategies.">Antimicrobial mechanisms of phagocytes and bacterial evasion strategies.</a> Nat Rev Microbiol. 7, 355-366 (2009).</li><li>Luzio, J., Pryor, P., Bright, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lysosomes:+fusion+and+function.">Lysosomes: fusion and function.</a> Nat. Rev. Mol. Cell Biol. 8, 622-632 (2007).</li><li>Huotari, J., Helenius, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endosome+maturation.">Endosome maturation.</a> EMBO J. 30, 3481-3500 (2011).</li><li>Luzio, J. P., 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=Lysosome-endosome+fusion+and+lysosome+biogenesis.">Lysosome-endosome fusion and lysosome biogenesis.</a> J. Cell. Sci. 113 (pt 9), 1515-1524 (2000).</li><li>Eissenberg, L., Goldman, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fusion+of+lysosomes+with+phagosomes+containing+Histoplasma+capsulatum:+use+of+fluoresceinated+dextran).">Fusion of lysosomes with phagosomes containing Histoplasma capsulatum: use of fluoresceinated dextran).</a> Adv. Exp. Med. Biol. 239, 53-61 (1988).</li><li>de Souza Carvalho, 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=Internalization,+phagolysosomal+biogenesis+and+killing+of+mycobacteria+in+enucleated+epithelial+cells.">Internalization, phagolysosomal biogenesis and killing of mycobacteria in enucleated epithelial cells.</a> Cell. Microbiol. 13, 1234-1249 (2011).</li><li>Wang, Y. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+and+sequential+delivery+of+fluorescent+lysosomal+probes+into+phagosomes+in+mouse+peritoneal+macrophages.">Differential and sequential delivery of fluorescent lysosomal probes into phagosomes in mouse peritoneal macrophages.</a> J. Cell Biol. 104, 1749-1754 (1987).</li><li>Harrison, R. E., Bucci, C., Vieira, O. V., Schroer, T. A., Grinstein, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phagosomes+Fuse+with+Late+Endosomes+and/or+Lysosomes+by+Extension+of+Membrane+Protrusions+along+Microtubules:+Role+of+Rab7+and+RILP.">Phagosomes Fuse with Late Endosomes and/or Lysosomes by Extension of Membrane Protrusions along Microtubules: Role of Rab7 and RILP.</a> Mol. Cell. Biol. 23, 6494-6506 (2003).</li><li>Huynh, K. K., 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=LAMP+proteins+are+required+for+fusion+of+lysosomes+with+phagosomes.">LAMP proteins are required for fusion of lysosomes with phagosomes.</a> EMBO J. 26, 313-324 (2007).</li><li>Kasmapour, B., Gronow, A., Bleck, C., Hong, W., Gutierrez, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Size-dependent+mechanism+of+cargo+sorting+during+lysosome-phagosome+fusion+is+controlled+by+Rab34.">Size-dependent mechanism of cargo sorting during lysosome-phagosome fusion is controlled by Rab34.</a> Proc. Natl. Acad. Sci. U.S.A. 109, 20485-20490 (2012).</li><li>Snijder, B., 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=Population+context+determines+cell-to-cell+variability+in+endocytosis+and+virus+infection.">Population context determines cell-to-cell variability in endocytosis and virus infection.</a> Nature. 461, 520-523 (2009).</li><li>Knight, M., Roberts, S., Lee, D., Bader, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Live+cell+imaging+using+confocal+microscopy+induces+intracellular+calcium+transients+and+cell+death.">Live cell imaging using confocal microscopy induces intracellular calcium transients and cell death.</a> Am. J. Physiol. Cell Physiol. 284, 9 (2003).</li><li>Hemmi, H., 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+Toll-like+receptor+recognizes+bacterial+DNA.">A Toll-like receptor recognizes bacterial DNA.</a> Nature. 408, 740-745 (2000).</li><li>Underhill, D., Ozinsky, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toll-like+receptors:+key+mediators+of+microbe+detection.">Toll-like receptors: key mediators of microbe detection.</a> Curr. Opin. Immunol. 14, 103-110 (2002).</li><li>Bohdanowicz, M., Cos&#237;o, G., Backer, J., Grinstein, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Class+I+and+class+III+phosphoinositide+3-kinases+are+required+for+actin+polymerization+that+propels+phagosomes.">Class I and class III phosphoinositide 3-kinases are required for actin polymerization that propels phagosomes.</a> J. Cell Biol. 191, 999-1012 (2010).</li><li>Hoffmann, 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=Initial+receptor-ligand+interactions+modulate+gene+expression+and+phagosomal+properties+during+both+early+and+late+stages+of+phagocytosis.">Initial receptor-ligand interactions modulate gene expression and phagosomal properties during both early and late stages of phagocytosis.</a> Eur. J. Cell Biol. 89, 693-704 (2010).</li><li>Yates, R., Hermetter, A., Russell, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+kinetics+of+phagosome+maturation+as+a+function+of+phagosome/lysosome+fusion+and+acquisition+of+hydrolytic+activity.">The kinetics of phagosome maturation as a function of phagosome/lysosome fusion and acquisition of hydrolytic activity.</a> Traffic. 6, 413-420 (2005).</li><li>Savina, A., 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=NOX2+controls+phagosomal+pH+to+regulate+antigen+processing+during+crosspresentation+by+dendritic+cells.">NOX2 controls phagosomal pH to regulate antigen processing during crosspresentation by dendritic cells.</a> Cell. 126, 205-218 (2006).</li><li>Yates, R., Hermetter, A., Russell, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recording+phagosome+maturation+through+the+real-time,+spectrofluorometric+measurement+of+hydrolytic+activities.">Recording phagosome maturation through the real-time, spectrofluorometric measurement of hydrolytic activities.</a> Methods Mol. Biol. 531, 157-171 (2009).</li><li>Russell, D., Vanderven, B., Glennie, S., Mwandumba, H., Heyderman, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+macrophage+marches+on+its+phagosome:+dynamic+assays+of+phagosome+function.">The macrophage marches on its phagosome: dynamic assays of phagosome function.</a> Nat. Rev. Immunol. 9, 594-600 (2009).</li><li>Hoffmann, 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=Autonomous+phagosomal+degradation+and+antigen+presentation+in+dendritic+cells.">Autonomous phagosomal degradation and antigen presentation in dendritic cells.</a> Proc. Natl. Acad. Sci. U.S.A. 109, 14556-14561 (2012).</li><li>Tan, S., Sukumar, N., Abramovitch, R., Parish, T., Russell, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mycobacterium+tuberculosis+Responds+to+Chloride+and+pH+as+Synergistic+Cues+to+the+Immune+Status+of+its+Host+Cell.">Mycobacterium tuberculosis Responds to Chloride and pH as Synergistic Cues to the Immune Status of its Host Cell.</a> PLoS Pathog. 9, (2013).</li><li>Aziz, M., Yang, W. -. L., Wang, P., Coliganet, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+phagocytic+engulfment+of+apoptotic+cells+by+macrophages+using+pHrodo+succinimidyl+ester.">Measurement of phagocytic engulfment of apoptotic cells by macrophages using pHrodo succinimidyl ester.</a> Current protocols in immunology. 14, (2013).</li><li>Rogers, L., Foster, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+dynamic+phagosomal+proteome+and+the+contribution+of+the+endoplasmic+reticulum.">The dynamic phagosomal proteome and the contribution of the endoplasmic reticulum.</a> Proc. Natl. Acad. Sci. U.S.A. 104, 18520-18525 (2007).</li><li>Russell, D. G., Vanderven, B. C., Glennie, S., Mwandumba, H., Heyderman, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+macrophage+marches+on+its+phagosome:+dynamic+assays+of+phagosome+function.">The macrophage marches on its phagosome: dynamic assays of phagosome function.</a> Nat. Rev. Immunol. 9, 594-600 (2009).</li><li>Savina, A., Vargas, P., Guermonprez, P., Lennon, A. -. M., Amigorena, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+pH,+ROS+production,+maturation,+and+degradation+in+dendritic+cell+phagosomes+using+cytofluorometry-based+assays.">Measuring pH, ROS production, maturation, and degradation in dendritic cell phagosomes using cytofluorometry-based assays.</a> Methods. Mol. Biol. 595, 383-402 (2010).</li></ol>

Les auteurs n&#39;ont rien à révéler.

Dans la section suivante, nous allons discuter des étapes critiques de la méthode présentée et de ses limites. En outre, nous allons connecter certains des problèmes communs avec leurs solutions, apporter des modifications possibles et considérer les avantages de notre méthode ainsi que les méthodes complémentaires appropriés pour cette approche. La préparation des billes, y compris le couplage de l&#39;IgG à la surface des billes, est essentielle et l&#39;utilisation de prépara...

Phagocytes professionnels, y compris les macrophages, joue un crucial dans le système immunitaire. En plus d&#39;être la première ligne de défense du système immunitaire inné, ils jouent également un rôle essentiel dans l&#39;activation de l&#39;immunité adaptative par leur signalisation et présentant l&#39;antigène rôle 1-3. Bien que la fonction des phagocytes professionnels est à multiples facettes, phagosome maturation est l&#39;épine dorsale critique de la fonction de traitement bactéricide et l&#39;antigène des phagocytes professionnels 4,5. Lors de l&#39;immersion et de l&#39;absorption d&#39;une cible phagocytaires, tels que des bactéries médiée par le récepteur, le phagosome naissante passe par une séquence complexe et bien orchestrée de l&#39;interaction et des échanges avec des compartiments du réseau d&#39;endocytose et plusieurs autres organites cellulaires 6. La nature des composés échangé avec ces entités cellulaires ainsi que la réglementation et le calendrier des événements de fusion détermine la luminale phagosome milieu et les phagoscomposition de omal de membrane et donc 7, le sort du phagosome échéant le 8. La pertinence physiologique de maturation du phagosome est illustré par les diverses stratégies employées par les différents agents pathogènes intracellulaires d&#39;échapper, arrêter ou renverser phagosome maturation 9. La plupart de ces stratégies prévenir directement ou indirectement la phase finale et critique du processus de maturation du phagosome: la fusion de phagosome avec des compartiments fin endosomal / lysosomales, qui leur apporte l&#39;essentiel des enzymes hydrolytiques et des facteurs anti-bactériennes du phagosome maturité 7 , 8,10. L&#39;analyse de cette étape finale et critique peut donc nous fournir des indicateurs solides sur l&#39;état de maturation des phagosomes et si l&#39;état physiologique naturel est d&#39;être positivement ou négativement affecté dans les paramètres expérimentaux particuliers qui sont utilisés. Le compartiment endosomes tardifs / lysosomess sont généralement considérés comme les compartiments de raccordement de la voie d&#39;endocytose, définis et distingués des compartiments d&#39;endocytose début par la présence de divers, en scène, des molécules spécifiques de marqueurs. Par exemple des enzymes hydrolytiques ou composants de la membrane telles que les protéines de la membrane lysosomale associés (lampes) entre autres 11. Le terminal endocytose compartiments-appelée simplement comme lysosomes-servent également de l&#39;emplacement principal pour les phases finales de la digestion à la fin de la voie de phagocytose / 12 endocytose. De cette manière, des sondes non digestibles peuvent être chargés par l&#39;intermédiaire de l&#39;endocytose et macropinocytose le milieu extracellulaire et transportés à travers la voie d&#39;endocytose vers les lysosomes, où il s&#39;accumule 13,14 après avoir suivi un cycle défini de l&#39;absorption et de chasse. sondes conjugué à un fluorophore pour la microscopie fluorescente telle que le dextrane polymère organique non digestible sont couramment utilisés comme endocyticprobes 15-17. <p class = &quot;jove_content&quot;&gt; Dans cette méthode, nous décrivons l&#39;utilisation de microbilles recouvertes d&#39;IgG en tant que cargaison phagocytaire d&#39;enquêter phagosome maturation par l&#39;analyse de la livraison de contenu lysosomale luminale de phagosomes. En utilisant une sonde dextran conjugué à un fluorophore comme un marqueur facilement détectable des lysosomes dans les macrophages os vivant de moelle dérivés (BMM) et vidéo en temps réel l&#39;imagerie avec un microscope confocal à balayage laser microscope, nous suivons le processus dynamique de la livraison de marchandises en phagosomes à haute résolution temporelle. Nous décrivons ensuite comment les données d&#39;imagerie time-lapse collectées peuvent être évaluées en utilisant open-source et disponible gratuitement le logiciel d&#39;analyse d&#39;image, Fidji (ou ImageJ), une analyse statistique en utilisant Microsoft Excel et présenté en utilisant le logiciel GraphPad Prism 14,18. Après la description de notre méthode, des expériences analogues peuvent être conçus en utilisant les paramètres et les facteurs modifiés pour étudier leur influence sur la maturation du phagosome, pratiquement n&#39;importe quel otson type de cellules phagocytaires primaires ou de lignées cellulaires adhérentes, perte génétique des expériences de fonction incluant le gène knock-out et knock-down, mutants ou l&#39;expression de protéines de fusion, phagocytaires-cibles, les produits de revêtement de microbilles, des sondes endosomal / lysosomal et des facteurs comme une cytokines, des inhibiteurs chimiques ou siRNA entre autres, sont autant de variables qui peuvent être appliqués à l&#39;approche de base de cette méthode. Nous définissons l&#39;objectif et les exigences de base de cette méthode comme suit: <ul type="disc"><li> Objectif de la méthode: pour permettre l&#39;observation directe, quantitative et qualitative et l&#39;analyse de la maturation du phagosome avec une haute résolution temporelle dans les cellules phagocytaires vivre. </li><li> Cargaison phagocytaire: une microparticule revêtue de manière appropriée ou d&#39;une cible biologique. Ici, nous utilisons recouvertes d&#39;IgG 3 um microparticules sphériques de polystyrène qui sont facilement internalisées via le récepteur Fc-γ phagocytose médiée. Sinon, tout micro-organisme ou micro revêturoparticle pour lequel un récepteur phagocytaire est présent sur les cellules peut être utilisé. </li><li> Les cellules phagocytaires: les cellules phagocytaires adhérentes exprimant les récepteurs phagocytaires appropriées. Ici, nous utilisons primaires BMMS de souris qui expriment les récepteurs Fc abondamment-γ. En variante, les cellules dendritiques (DC), les monocytes ou les cellules épithéliales phagocytaires ou à leurs mutants ou variants génétiques knock-out peuvent être utilisés. </li><li> Lysosomale cargaison: Une sonde lysosomale marqué par fluorescence. Ici, le Texas Red-conjugué 70,000 kiloDaltons dextran (Dex70kD) est utilisé en tant que la cargaison de luminal des lysosomes. En variante, n&#39;importe quel marqueur détectable par fluorescence d&#39;un compartiment cellulaire ou organite, ou une sonde appropriée pour les propriétés de phagosome tels que l&#39;acidité ou la capacité de dégradation, peut être utilisée pour étudier la progression de la maturation phagosome. </li><li> Les facteurs d&#39;influence: Par exemple, les molécules, les composés chimiques, gène knock-down, ou l&#39;expression transitoire de protéines mutantes pourraient signalisation. Ici, nous avons FÖRGun l&#39;utilisation d&#39;un tel facteur pour des raisons de simplicité, mais pour un exemple récent avec l&#39;expression de la protéine mutante et knock-down facteurs influençant s&#39;il vous plaît voir Kasmapour et al. 18 Tout facteur qui peut affecter la phagocytose ou les circonstances et la mobilité des phagosomes et / ou les compartiments qui interagissent avec les phagosomes échéance pourraient être utilisés. </li></ul>

<table border="0" cellpadding="0" cellspacing="0" width="610">
	<tbody>
		<tr>
			<td>Dulbecco&#39;s Modified Eagles Medium (D-MEM)</td>
			<td>PAA, Austria</td>
			<td>E15-009</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#39;s Modified Eagles Medium without phenol red (D-MEM)</td>
			<td>PAA, Austria</td>
			<td>E15-047</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum (FBS)</td>
			<td>PAA, Austria</td>
			<td>A15-151</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Glutamine</td>
			<td>PAA, Austria</td>
			<td>M11-004</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS</td>
			<td>PAA, Austria</td>
			<td>H15-002</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin</td>
			<td>PAA, Austria</td>
			<td>P11-010</td>
			<td></td>
		</tr>
		<tr>
			<td>WillCo-dish&#174; Glass bottom dish (35 mm &#8709;, #1.5)</td>
			<td>WillCo Wells, Netherlands</td>
			<td>GWSt-3522</td>
			<td></td>
		</tr>
		<tr>
			<td>CELLviewTM glass bottom dish, 35 mm</td>
			<td>Greiner Bio one, Germany</td>
			<td>627871</td>
			<td>Alternative: Available as segmented</td>
		</tr>
		<tr>
			<td>Carboxylated latex microspheres</td>
			<td>Polysciences, USA</td>
			<td>#09850</td>
			<td>Available in different diameters, we used 3 &#956;m</td>
		</tr>
		<tr>
			<td>Polystyrene microparticles</td>
			<td>Kisker Biotech, Germany</td>
			<td>PPs-3.0COOH</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton-X 100</td>
			<td>ROTH, Germany</td>
			<td>305.1.3</td>
			<td></td>
		</tr>
		<tr>
			<td>mouse whole IgG</td>
			<td>Rockland, USA</td>
			<td>010-0102</td>
			<td></td>
		</tr>
		<tr>
			<td>EDAC crosslinker</td>
			<td>Sigma-Aldrich, USA</td>
			<td>E6383-1g</td>
			<td></td>
		</tr>
		<tr>
			<td>10 mM Tris</td>
			<td>Sigma-Aldrich,USA</td>
			<td>T1503</td>
			<td></td>
		</tr>
		<tr>
			<td>1-ml syringe Omnifix -F</td>
			<td>B.Braun, Germany</td>
			<td>9161406V</td>
			<td></td>
		</tr>
		<tr>
			<td>26&#160;G needle (0.45*25 mm)</td>
			<td>B.Baun, Germany</td>
			<td>4657683</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI 1640</td>
			<td>PAA, Austria</td>
			<td>E15-039</td>
			<td></td>
		</tr>
		<tr>
			<td>Horse Serum</td>
			<td>Gibco, USA</td>
			<td>16050-122</td>
			<td></td>
		</tr>
		<tr>
			<td>MES hydrate</td>
			<td>Sigma-Aldrich, USA</td>
			<td>M2933</td>
			<td></td>
		</tr>
		<tr>
			<td>0.2 &#956;M syringe mounted filter</td>
			<td>Sartorius, Germany</td>
			<td>83.1826.001</td>
			<td></td>
		</tr>
	</tbody>
</table>

study of phagolysosome biogenesis in live macrophages

Les cellules phagocytaires jouent un rôle majeur dans le système immunitaire inné en enlevant et en éliminant les micro-organismes envahisseurs dans leurs phagosomes. Phagosome maturation est le processus complexe et étroitement réglementé au cours de laquelle un phagosome naissant subit une transformation radicale par des interactions bien orchestrées avec divers organites cellulaires et des compartiments dans le cytoplasme. Ce processus, qui est essentiel pour la fonction physiologique des cellules phagocytaires en dotant phagosomes avec leurs propriétés lytiques et bactéricides, culmine dans la fusion des phagosomes avec les lysosomes et la biogenèse des phagolysosomes qui est considéré comme la dernière étape critique de la maturation pour phagosomes. Dans ce rapport, nous décrivons une méthode basée imagerie des cellules vivantes pour l&#39;analyse qualitative et quantitative de la dynamique de lysosome pour phagosome livraison de contenu, ce qui est une caractéristique de phagolysosome biogenèse. Cette approche utilise des microbilles recouvertes d&#39;IgG comme un modèle pour phagocytose et molécules de dextran fluorophore conjugué comme sonde de fret lysosomale luminale, afin de suivre la livraison de contenu dynamique de lysosmal aux phagosomes en temps réel dans les macrophages vivants en utilisant l&#39;imagerie time-lapse et la microscopie confocale à balayage laser. Ici, nous décrivons en détail l&#39;arrière-plan, les étapes de préparation et de la mise en place, étape par étape expérimentale pour permettre un déploiement facile et précis de ce procédé à d&#39;autres laboratoires. Notre méthode décrite est simple, robuste, et surtout, peuvent être facilement adaptés à l&#39;étude des interactions phagosome et la maturation dans les différents systèmes et sous divers paramètres expérimentaux tels que l&#39;utilisation de différents types de cellules phagocytaires, des expériences de perte de fonction, différentes sondes, et particules phagocytaires.

La préparation correcte des cellules et les billes pour l&#39;imagerie est critique. Figure 1 montre le contour de l&#39;ensemencement, la sonde de chargement et les étapes de formation d&#39;image initiaux dans ce procédé, sur la base de notre protocole optimisé pour BMMS. Il est donc essentiel que les paramètres de protocole être testées et optimisées en fonction du type de cellules et des sondes qui doivent être utilisés. Après addition des billes recouvertes ...

Watch this Scientific Journal Video about Study of Phagolysosome Biogenesis in Live Macrophages at JoVE.com

Study of Phagolysosome Biogenesis in Live Macrophages

Étude de phagolysosome biogenèse dans les macrophages en direct

Phagocytic cells play a major role in the innate immune system by removing and eliminating invading microorganisms in their phagosomes. Phagosome ...

study-of-phagolysosome-biogenesis-in-live-macrophages

Research

JoVE Journal

Immunology and Infection

14.3K vues.  Helmholtz Centre for Infection Research. Étude de phagolysosome biogenèse dans les macrophages en direct

Vidéo: Study of Phagolysosome Biogenesis in Live Macrophages

Use of an Optical Trap for Study of Host-Pathogen Interactions for Dynamic Live Cell Imaging

Dynamic live cell imaging allows direct visualization of real-time interactions between cells of the immune system1, 2; however, the lack of spatial and temporal control between the phagocytic cell and microbe has rendered focused observations into the initial interactions of host response to pathogens difficult. Historically, intercellular contact events such as phagocytosis3 have been imaged by mixing two cell types, and then continuously scanning the field-of-view to find serendipitous intercellular contacts at the appropriate stage of interaction. The stochastic nature of these events renders this process tedious, and it is difficult to observe early or fleeting events in cell-cell contact by this approach. This method requires finding cell pairs that are on the verge of contact, and observing them until they consummate their contact, or do not. To address these limitations, we use optical trapping as a non-invasive, non-destructive, but fast and effective method to position cells in culture.
Optical traps, or optical tweezers, are increasingly utilized in biological research to capture and physically manipulate cells and other micron-sized particles in three dimensions4. Radiation pressure was first observed and applied to optical tweezer systems in 19705, 6, and was first used to control biological specimens in 19877. Since then, optical tweezers have matured into a technology to probe a variety of biological phenomena8-13.
We describe a method14 that advances live cell imaging by integrating an optical trap with spinning disk confocal microscopy with temperature and humidity control to provide exquisite spatial and temporal control of pathogenic organisms in a physiological environment to facilitate interactions with host cells, as determined by the operator. Live, pathogenic organisms like Candida albicans and Aspergillus fumigatus, which can cause potentially lethal, invasive infections in immunocompromised individuals15, 16 (e.g. AIDS, chemotherapy, and organ transplantation patients), were optically trapped using non-destructive laser intensities and moved adjacent to macrophages, which can phagocytose the pathogen. High resolution, transmitted light and fluorescence-based movies established the ability to observe early events of phagocytosis in living cells. To demonstrate the broad applicability in immunology, primary T-cells were also trapped and manipulated to form synapses with anti-CD3 coated microspheres in vivo, and time-lapse imaging of synapse formation was also obtained. By providing a method to exert fine spatial control of live pathogens with respect to immune cells, cellular interactions can be captured by fluorescence microscopy with minimal perturbation to cells and can yield powerful insight into early responses of innate and adaptive immunity.

A method is described to individually select, manipulate, and image live pathogens using an optical trap coupled to a spinning disk microscope. The optical trap provides spatial and temporal control of organisms and places them adjacent to host cells. Fluorescence microscopy captures dynamic intercellular interactions with minimal perturbation to cells.

L&#39;utilisation d&#39;un piège optique pour l&#39;étude des interactions hôtes pathogènes pour l&#39;imagerie cellulaire dynamique en direct

Dynamic live cell imaging allows direct visualization of real-time interactions between cells of the immune system1, 2; however, the lack of spatial and ...

Recherche

Immunologie et infection

Depletion and Reconstitution of Macrophages in Mice

Macrophages are critical players in the innate immune response to infectious challenge or injury, initiating the innate immune response and directing the acquired immune response. Macrophage dysfunction can lead to an inability to mount an appropriate immune response and as such, has been implicated in many disease processes, including inflammatory bowel diseases. Macrophages display polarized phenotypes that are broadly divided into two categories. Classically activated macrophages, activated by stimulation with IFN&gamma; or LPS, play an essential role in response to bacterial challenge whereas alternatively activated macrophages, activated by IL-4 or IL-13, participate in debris scavenging and tissue remodeling and have been implicated in the resolution phase of inflammation. During an inflammatory response in vivo, macrophages are found amid a complex mixture of infiltrating immune cells and may participate by exacerbating or resolving inflammation. To define the role of macrophages in situ in a whole animal model, it is necessary to examine the effect of depleting macrophages from the complex environment. To ask questions about the role of macrophage phenotype in situ, phenotypically defined polarized macrophages can be derived ex vivo, from bone marrow aspirates and added back to mice, with or without prior depletion of macrophages. In the protocol presented here clodronate-containing liposomes, versus PBS injected controls, were used to deplete colonic macrophages during dextran sodium sulfate (DSS)-induced colitis in mice. In addition, polarized macrophages were derived ex vivo and transferred to mice by intravenous injection. A caveat to this approach is that clodronate-containing liposomes deplete all professional phagocytes, including both dendritic cells and macrophages so to ensure the effect observed by depletion is macrophage-specific, reconstitution of phenotype by adoptive transfer of macrophages is necessary. Systemic macrophage depletion in mice can also be achieved by backcrossing mice onto a CD11b-DTR background, which is an excellent complementary approach. The advantage of clodronate-containing liposome-mediated depletion is that it does not require the time and expense involved in backcrossing mice and it can be used in mice regardless of the background of the mice (C57BL/6, BALB/c, or mixed background).

Macrophages play a central role in homeostasis and pathology in many tissues. The protocol presented here describes methods for depleting macrophages in vivo, deriving polarized macrophages from bone marrow aspirates, and adoptively transferring macrophages into mice. These techniques allow determination of the role that polarized macrophages play in health and disease.

L&#39;épuisement et la reconstitution des macrophages chez la souris

Macrophages are critical players in the innate  immune response to infectious challenge or injury, initiating the innate immune  response and directing ...

Establishment of an In vitro System to Study Intracellular Behavior of Candida glabrata in Human THP-1 Macrophages

A cell culture model system, if a close mimic of host environmental conditions, can serve as an inexpensive, reproducible and easily manipulatable alternative to animal model systems for the study of a specific step of microbial pathogen infection. A human monocytic cell line THP-1 which, upon phorbol ester treatment, is differentiated into macrophages, has previously been used to study virulence strategies of many intracellular pathogens including Mycobacterium tuberculosis. Here, we discuss a protocol to enact an in vitro cell culture model system using THP-1 macrophages to delineate the interaction of an opportunistic human yeast pathogen Candida glabrata with host phagocytic cells. This model system is simple, fast, amenable to high-throughput mutant screens, and requires no sophisticated equipment. A typical THP-1 macrophage infection experiment takes approximately 24 hr with an additional 24-48 hr to allow recovered intracellular yeast to grow on rich medium for colony forming unit-based viability analysis. Like other in vitro model systems, a possible limitation of this approach is difficulty in extrapolating the results obtained to a highly complex immune cell circuitry existing in the human host. However, despite this, the current protocol is very useful to elucidate the strategies that a fungal pathogen may employ to evade/counteract antimicrobial response and survive, adapt, and proliferate in the nutrient-poor environment of host immune cells.

Establishment of an In vitro System to Study Intracellular Behavior of Candida glabrata in Human THP-1 Macrophages

The current article outlines a protocol to establish an in vitro cell culture model system to study the interaction of a facultative intracellular human fungal pathogen Candida glabrata with human macrophages which will be a useful tool to advance our knowledge of fungal virulence mechanisms.

Mise en place d&#39;un<em&gt; In vitro</em&gt; Système d&#39;étudier le comportement intracellulaire de<em&gt; Candida glabrata</em&gt; En droits macrophages THP-1

A cell culture model system, if a close mimic of host environmental conditions, can serve as an inexpensive, reproducible and easily manipulatable ...

Use of Shigella flexneri to Study Autophagy-Cytoskeleton Interactions

Shigella flexneri is an intracellular pathogen that can escape from phagosomes to reach the cytosol, and polymerize the host actin cytoskeleton to promote its motility and dissemination. New work has shown that proteins involved in actin-based motility are also linked to autophagy, an intracellular degradation process crucial for cell autonomous immunity. Strikingly, host cells may prevent actin-based motility of S. flexneri by compartmentalizing bacteria inside &#8216;septin cages&#8217; and targeting them to autophagy. These observations indicate that a more complete understanding of septins, a family of filamentous GTP-binding proteins, will provide new insights into the process of autophagy. This report describes protocols to monitor autophagy-cytoskeleton interactions caused by S. flexneri in vitro using tissue culture cells and in vivo using zebrafish larvae. These protocols enable investigation of intracellular mechanisms that control bacterial dissemination at the molecular, cellular, and whole organism level.

Use of Shigella flexneri to Study Autophagy-Cytoskeleton Interactions

To counteract pathogen dissemination, host cells reorganize their cytoskeleton to compartmentalize bacteria and induce autophagy. Using Shigella infection of tissue culture cells, host and pathogen determinants underlying this process are identified and characterized. Using zebrafish models of Shigella infection, the role of discovered molecules and mechanisms are investigated in vivo.

Utilisation d&#39;<em&gt; Shigella flexneri</em&gt; Pour étudier les interactions de l&#39;autophagie cytosquelette

Shigella flexneri is an intracellular pathogen that can escape from phagosomes to reach the cytosol, and polymerize the host actin cytoskeleton to promote ...

Proteomic Profiling of Macrophages by 2D Electrophoresis

The goal of the two-dimensional (2D) electrophoresis protocol described here is to show how to analyse the phenotype of human cultured macrophages. The key role of macrophages has been shown in various pathological disorders such as inflammatory, immunological, and infectious diseases. In this protocol, we use primary cultures of human monocyte-derived macrophages that can be differentiated into the M1 (pro-inflammatory) or the M2 (anti-inflammatory) phenotype. This in vitro model is reliable for studying the biological activities of M1 and M2 macrophages and also for a proteomic approach. Proteomic techniques are useful for comparing the phenotype and behaviour of M1 and M2 macrophages during host pathogenicity. 2D gel electrophoresis is a powerful proteomic technique for mapping large numbers of proteins or polypeptides simultaneously. We describe the protocol of 2D electrophoresis using fluorescent dyes, named 2D Differential Gel Electrophoresis (DIGE). The M1 and M2 macrophages proteins are labelled with cyanine dyes before separation by isoelectric focusing, according to their isoelectric point in the first dimension, and their molecular mass, in the second dimension. Separated protein or polypeptidic spots are then used to detect differences in protein or polypeptide expression levels. The proteomic approaches described here allows the investigation of the macrophage protein changes associated with various disorders like host pathogenicity or microbial toxins.

Macrophages are the key cells involved in host pathogenicity. Macrophages display phenotypic and functional diversity that can be analysed and detected by proteomic analysis. This article describes how to perform 2D electrophoresis of primary cultures of human macrophages differentiated into M1 or M2 phenotype.

Protéomique profilage des macrophages par électrophorèse 2D

The goal of the two-dimensional (2D) electrophoresis protocol described here is to show how to analyse the phenotype of human cultured macrophages. The ...

Quantification of Cytosolic vs. Vacuolar Salmonella in Primary Macrophages by Differential Permeabilization

Intracellular bacterial pathogens can replicate in the cytosol or in specialized pathogen-containing vacuoles (PCVs). To reach the cytosol, bacteria like Shigella flexneri and Francisella novicida need to induce the rupture of the phagosome. In contrast, Salmonella typhimurium replicates in a vacuolar compartment, known as Salmonella-containing vacuole (SCV). However certain mutants of Salmonella fail to maintain SCV integrity and are thus released into the cytosol. The percentage of cytosolic vs. vacuolar bacteria on the level of single bacteria can be measured by differential permeabilization, also known as phagosome-protection assay. The approach makes use of the property of detergent digitonin to selectively bind cholesterol. Since the plasma membrane contains more cholesterol than other cellular membranes, digitonin can be used to selectively permeabilize the plasma membrane while leaving intracellular membranes intact. In brief, following infection with the pathogen expressing a fluorescent marker protein (e.g. mCherry among others), the plasma membrane of host cells is permeabilized with a short incubation in digitonin containing buffer. Cells are then washed and incubated with a primary antibody (coupled to a fluorophore of choice) directed against the bacterium of choice (e.g. anti-Salmonella-FITC) and washed again. If unmarked bacteria are used, an additional step can be done, in which all membranes are permeabilized and all bacteria stained with a corresponding antibody. Following the staining, the percentage of vacuolar and cytosolic bacteria can be quantified by FACS or microscopy by counting single or double-positive events. Here we provide experimental details for use of this technique with the bacterium Salmonella typhimurium. The advantage of this assay is that, in contrast to other assay, it provides a quantification on the level of single bacteria, and if analyzed by microscopy provides the exact number of cytosolic and vacuolar bacteria in a given cell.

Quantification of Cytosolic vs. Vacuolar Salmonella in Primary Macrophages by Differential Permeabilization

We describe the quantification of cytosolic and vacuolar Salmonella typhimurium in bone-marrow derived macrophages using differential digitonin permeabilization.

Quantification des cytosolique vs Vacuolar<em&gt; Salmonella</em&gt; Dans les macrophages primaires par différentiel Perméabilisation

Intracellular bacterial pathogens can replicate in the cytosol or in specialized pathogen-containing vacuoles (PCVs). To reach the cytosol, bacteria like ...

Phagosome Migration and Velocity Measured in Live Primary Human Macrophages Infected with HIV-1

Macrophages are phagocytic cells that play a major role at the crossroads between innate and specific immunity. They can be infected by the human immunodeficiency virus (HIV)-1 and because of their resistance to its cytopathic effects they can be considered to be persistent viral reservoirs. In addition, HIV-infected macrophages exhibit defective functions that contribute to the development of opportunistic diseases.
The exact mechanism by which HIV-1 impairs the phagocytic response of macrophages was unknown. We had previously shown that the uptake of various particulate material by macrophages was inhibited when they were infected with HIV-1. This inhibition was only partial and phagosomes did form within HIV-infected macrophages. Therefore, we focused on analyzing the fate of these phagosomes. Phagosome maturation is accompanied by migration of these compartments towards the cell center, where they fuse with lysosomes, generating phagolysosomes, responsible for degradation of the ingested material. We used IgG-opsonized Sheep Red Blood Cells as a target for phagocytosis. To measure the speed of centripetal movement of phagosomes in individual HIV-infected macrophages, we used a combination of bright field and fluorescence confocal microscopy. We established a method to calculate the distance of phagosomes towards the nucleus, and then to calculate the velocity of the phagosomes. HIV-infected cells were identified thanks to a GFP-expressing virus, but the method is applicable to non-infected cells or any type of infection or treatment.

We describe a method to measure the velocity of phagosomes moving towards the cell center in living cells infected with or without the human immunodeficiency virus (HIV) type 1, using spinning disk confocal fluorescence microscopy to identify fluorescent infected cells and bright field microscopy to detect phagosomes.

Phagosome Migration et Velocity Mesurée en direct primaire des macrophages humains infectés par le VIH-1

Macrophages are phagocytic cells that play a major role at the crossroads between innate and specific immunity. They can be infected by the human ...

Isolation of Salmonella typhimurium-containing Phagosomes from Macrophages

Salmonella typhimurium is a facultative intracellular bacterium that causes gastroenteritis in humans. After invasion of the lamina propria, S. typhimurium bacteria are quickly detected and phagocytized by macrophages, and contained in vesicles known as phagosomes in order to be degraded. Isolation of S. typhimurium-containing phagosomes have been widely used to study how S. typhimurium infection alters the process of phagosome maturation to prevent bacterial degradation. Classically, the isolation of bacteria-containing phagosomes has been performed by sucrose gradient centrifugation. However, this process is time-consuming, and requires specialized equipment and a certain degree of dexterity. Described here is a simple and quick method for the isolation of S. typhimurium-containing phagosomes from macrophages by coating the bacteria with biotin-streptavidin-conjugated magnetic beads. Phagosomes obtained by this method can be suspended in any buffer of choice, allowing the utilization of isolated phagosomes for a broad range of assays, such as protein, metabolite, and lipid analysis. In summary, this method for the isolation of S. typhimurium-containing phagosomes is specific, efficient, rapid, requires minimum equipment, and is more versatile than the classical method of isolation by sucrose gradient-ultracentrifugation.

Isolation of Salmonella typhimurium-containing Phagosomes from Macrophages

We describe here a simple and quick method for the isolation of Salmonella typhimurium-containing phagosomes from macrophages by coating the bacteria with biotin and streptavidin.

Isolement de Salmonella typhimurium-contenant des Phagosomes des Macrophages

Salmonella typhimurium is a facultative intracellular bacterium that causes gastroenteritis in humans. After invasion of the lamina propria, S. ...

Isolation and In Vitro Culture of Murine and Human Alveolar Macrophages

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

Isolation and In Vitro Culture of Murine and Human Alveolar Macrophages

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

Isolement et la Culture In Vitro de Macrophages alvéolaires murines et humaines

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

Flow Cytometric Measurement Of ROS Production In Macrophages In Response To Fc&#947;R Cross-linking

The oxidative or respiratory burst is used to describe the rapid consumption of oxygen and generation of reactive oxygen species (ROS) by phagocytes in response to various immune stimuli. ROS generated during immune activation exerts potent antimicrobial activity primarily through the ability of ROS to damage DNA and proteins, causing death of microorganisms. Being able to measure ROS production reproducibly and with ease is necessary in order to assess the contribution of various pathways and molecules to this mechanism of host defense. In this paper, we demonstrate the use of fluorescent probes and flow cytometry to detect ROS production. Although widely used, fluorescent measurement of ROS is notoriously problematic, especially with regards to measurement of ROS induced by specific and not mitogenic stimuli. We present a detailed methodology to detect ROS generated as a result of specific Fc&#947;R stimulation beginning with macrophage generation, priming, staining, Fc&#947;R cross-linking, and ending with flow cytometric analysis.

This study demonstrates the use of flow cytometry to detect reactive oxygen species (ROS) production resulting from activation of the Fc&#947;R. This method can be used to assess changes in the antimicrobial and redox signaling function of phagocytes in response to immune complexes, opsonized microorganisms, or direct Fc&#947;R cross-linking.

Mesure de débit par cytométrie en flux de Production de ROS dans les Macrophages en réponse à la réticulation FcγR

The oxidative or respiratory burst is used to describe the rapid consumption of oxygen and generation of reactive oxygen species (ROS) by phagocytes in ...