We thank Gon&#231;alo Moniz Institute, Fiocruz Bahia, Brazil and the department of microscopy for assistance. This work was supported by INOVA-FIOCRUZ number 79700287000, P.S.T.V. holds a grant for productivity in research from CNPq (305235/2019-2). Plasmids were kindly provided by Mauricio Terebiznik, University of Toronto, CA. The authors would like to thank Andris K. Walter for English language revision and manuscript copyediting assistance.

Cells were obtained from healthy donors following the approval of procedures by the National Research Ethics Committees (ID: 94648218.8.0000.0040).
1. Cell cultures
<ol>
	<li>Human monocyte-derived macrophages 
	NOTE: To obtain human monocyte-derived macrophages for in vitro differentiation into macrophages, collect blood from healthy donors and purify peripheral blood mononuclear cells (PBMC) as described by D. English and B. R. Andersen21.
	<ol>
		<li>...

<ol>
	<li>Goto, H., Lauletta Lindoso, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cutaneous+and+mucocutaneous+leishmaniasis.">Cutaneous and mucocutaneous leishmaniasis.</a> Infectious Disease Clinics of North America. 26 (2), 293-307 (2012).</li><li>World Health Organization. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+the+leishmaniases.">Control of the leishmaniases.</a> World Health Organization Technical Report Series. (949), 1 (2010).</li><li>Alexander, J., Russell, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+interaction+of+Leishmania+species+with+macrophages.">The interaction of Leishmania species with macrophages.</a> Advances in Parasitology. 31, 175-254 (1992).</li><li>Mosser, D. M., Rosenthal, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Leishmania-macrophage+interactions:+multiple+receptors,+multiple+ligands+and+diverse+cellular+responses.">Leishmania-macrophage interactions: multiple receptors, multiple ligands and diverse cellular responses.</a> Seminars in Cell Biology. 4 (5), 315-322 (1993).</li><li>Awasthi, A., Mathur, R. K., Saha, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immune+response+to+Leishmania+infection.">Immune response to Leishmania infection.</a> Indian Journal of Medical Research. 119 (6), 238-258 (2004).</li><li>Blackwell, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+macrophage+complement+and+lectin-like+receptors+in+binding+Leishmania+parasites+to+host+macrophages.">Role of macrophage complement and lectin-like receptors in binding Leishmania parasites to host macrophages.</a> Immunology Letters. 11 (3-4), 227-232 (1985).</li><li>Mosser, D. M., Edelson, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mouse+macrophage+receptor+for+C3bi+(CR3)+is+a+major+mechanism+in+the+phagocytosis+of+Leishmania+promastigotes.">The mouse macrophage receptor for C3bi (CR3) is a major mechanism in the phagocytosis of Leishmania promastigotes.</a> Journal of Immunology. 135 (4), 2785-2789 (1985).</li><li>Gough, P. J., Gordon, 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+role+of+scavenger+receptors+in+the+innate+immune+system.">The role of scavenger receptors in the innate immune system.</a> Microbes and Infection. 2 (3), 305-311 (2000).</li><li>Russell, D. G., Wilhelm, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+involvement+of+the+major+surface+glycoprotein+(gp63)+of+Leishmania+promastigotes+in+attachment+to+macrophages.">The involvement of the major surface glycoprotein (gp63) of Leishmania promastigotes in attachment to macrophages.</a> Journal of Immunology. 136 (7), 2613-2620 (1986).</li><li>Handman, E., Goding, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Leishmania+receptor+for+macrophages+is+a+lipid-containing+glycoconjugate.">The Leishmania receptor for macrophages is a lipid-containing glycoconjugate.</a> EMBO J. 4 (2), 329-336 (1985).</li><li>Holm, A., Tejle, K., Magnusson, K. E., Descoteaux, A., Rasmusson, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Leishmania+donovani+lipophosphoglycan+causes+periphagosomal+actin+accumulation:+correlation+with+impaired+translocation+of+PKCalpha+and+defective+phagosome+maturation.">Leishmania donovani lipophosphoglycan causes periphagosomal actin accumulation: correlation with impaired translocation of PKCalpha and defective phagosome maturation.</a> Cellular Microbiology. 3 (7), 439-447 (2001).</li><li>Vergne, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanism+of+phagolysosome+biogenesis+block+by+viable+Mycobacterium+tuberculosis.">Mechanism of phagolysosome biogenesis block by viable Mycobacterium tuberculosis.</a> Proceedings of the National Academy of Sciences of the United States of America. 102 (11), 4033-4038 (2005).</li><li>Courret, N., Lang, T., Milon, G., Antoine, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intradermal+inoculations+of+low+doses+of+Leishmania+major+and+Leishmania+amazonensis+metacyclic+promastigotes+induce+different+immunoparasitic+processes+and+status+of+protection+in+BALB/c+mice.">Intradermal inoculations of low doses of Leishmania major and Leishmania amazonensis metacyclic promastigotes induce different immunoparasitic processes and status of protection in BALB/c mice.</a> International Journal for Parasitology. 33 (12), 1373-1383 (2003).</li><li>Gutierrez, M. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Autophagy+induction+favours+the+generation+and+maturation+of+the+Coxiella-replicative+vacuoles.">Autophagy induction favours the generation and maturation of the Coxiella-replicative vacuoles.</a> Cellular Microbiology. 7 (7), 981-993 (2005).</li><li>Dermine, J. F., Scianimanico, S., Prive, C., Descoteaux, A., 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=Leishmania+promastigotes+require+lipophosphoglycan+to+actively+modulate+the+fusion+properties+of+phagosomes+at+an+early+step+of+phagocytosis.">Leishmania promastigotes require lipophosphoglycan to actively modulate the fusion properties of phagosomes at an early step of phagocytosis.</a> Cellular Microbiology. 2 (2), 115-126 (2000).</li><li>Desjardins, M., Descoteaux, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inhibition+of+phagolysosomal+biogenesis+by+the+Leishmania+lipophosphoglycan.">Inhibition of phagolysosomal biogenesis by the Leishmania lipophosphoglycan.</a> Journal of Experimental Medicine. 185 (12), 2061-2068 (1997).</li><li>Antoine, J. C., Prina, E., Lang, T., Courret, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+biogenesis+and+properties+of+the+parasitophorous+vacuoles+that+harbour+Leishmania+in+murine+macrophages.">The biogenesis and properties of the parasitophorous vacuoles that harbour Leishmania in murine macrophages.</a> Trends in Microbiology. 6 (10), 392-401 (1998).</li><li>Alexander, J., 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=An+essential+role+for+IL-13+in+maintaining+a+non-healing+response+following+Leishmania+mexicana+infection.">An essential role for IL-13 in maintaining a non-healing response following Leishmania mexicana infection.</a> European Journal of Immunology. 32 (10), 2923-2933 (2002).</li><li>Aderem, A., Underhill, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanisms+of+phagocytosis+in+macrophages.">Mechanisms of phagocytosis in macrophages.</a> Annual Review of Immunology. 17, 593-623 (1999).</li><li>Olivier, M., Gregory, D. J., Forget, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subversion+mechanisms+by+which+Leishmania+parasites+can+escape+the+host+immune+response:+a+signaling+point+of+view.">Subversion mechanisms by which Leishmania parasites can escape the host immune response: a signaling point of view.</a> Clinical Microbiology Reviews. 18 (2), 293-305 (2005).</li><li>English, D., Andersen, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-step+separation+of+red+blood+cells.+Granulocytes+and+mononuclear+leukocytes+on+discontinuous+density+gradients+of+Ficoll-Hypaque.">Single-step separation of red blood cells. Granulocytes and mononuclear leukocytes on discontinuous density gradients of Ficoll-Hypaque.</a> Journal of Immunology Methods. 5 (3), 249-252 (1974).</li><li>Petersen, A. 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=17-AAG+kills+intracellular+Leishmania+amazonensis+while+reducing+inflammatory+responses+in+infected+macrophages.">17-AAG kills intracellular Leishmania amazonensis while reducing inflammatory responses in infected macrophages.</a> PLoS One. 7 (11), 49496 (2012).</li><li>Maess, M. B., Wittig, B., Lorkowski, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+efficient+transfection+of+human+THP-1+macrophages+by+nucleofection.">Highly efficient transfection of human THP-1 macrophages by nucleofection.</a> Journal of Visualized Experiments. (91), e51960 (2014).</li><li>Berges, 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=End-binding+1+protein+overexpression+correlates+with+glioblastoma+progression+and+sensitizes+to+Vinca-alkaloids+in+vitro+and+in+vivo.">End-binding 1 protein overexpression correlates with glioblastoma progression and sensitizes to Vinca-alkaloids in vitro and in vivo.</a> Oncotarget. 5 (24), 12769-12787 (2014).</li><li>Franco, L. 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=The+Ubiquitin+Ligase+Smurf1+Functions+in+Selective+Autophagy+of+Mycobacterium+tuberculosis+and+Anti-tuberculous+Host+Defense.">The Ubiquitin Ligase Smurf1 Functions in Selective Autophagy of Mycobacterium tuberculosis and Anti-tuberculous Host Defense.</a> Cell Host &amp; Microbe. 22 (3), 421-423 (2017).</li><li>Corbett-Nelson, E. F., Mason, D., Marshall, J. G., Collette, Y., 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=Signaling-dependent+immobilization+of+acylated+proteins+in+the+inner+monolayer+of+the+plasma+membrane.">Signaling-dependent immobilization of acylated proteins in the inner monolayer of the plasma membrane.</a> Journal of Cell Biology. 174 (2), 255-265 (2006).</li><li>Yeung, T., 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=Receptor+activation+alters+inner+surface+potential+during+phagocytosis.">Receptor activation alters inner surface potential during phagocytosis.</a> Science. 313 (5785), 347-351 (2006).</li><li>Romano, P. S., Gutierrez, M. G., Beron, W., Rabinovitch, M., Colombo, M. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+autophagic+pathway+is+actively+modulated+by+phase+II+Coxiella+burnetii+to+efficiently+replicate+in+the+host+cell.">The autophagic pathway is actively modulated by phase II Coxiella burnetii to efficiently replicate in the host cell.</a> Cellular Microbiology. 9 (4), 891-909 (2007).</li><li>Vieira, O. V., 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=Modulation+of+Rab5+and+Rab7+recruitment+to+phagosomes+by+phosphatidylinositol+3-kinase.">Modulation of Rab5 and Rab7 recruitment to phagosomes by phosphatidylinositol 3-kinase.</a> Molecular and Cellular Biology. 23 (7), 2501-2514 (2003).</li><li>Roberts, R. L., Barbieri, M. A., Ullrich, J., Stahl, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamics+of+rab5+activation+in+endocytosis+and+phagocytosis.">Dynamics of rab5 activation in endocytosis and phagocytosis.</a> Journal of Leukocyte Biology. 68 (5), 627-632 (2000).</li><li>Vitelli, 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=Role+of+the+small+GTPase+Rab7+in+the+late+endocytic+pathway.">Role of the small GTPase Rab7 in the late endocytic pathway.</a> Journal of Biological Chemistry. 272 (7), 4391-4397 (1997).</li><li>Matte, 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=Leishmania+major+Promastigotes+Evade+LC3-Associated+Phagocytosis+through+the+Action+of+GP63.">Leishmania major Promastigotes Evade LC3-Associated Phagocytosis through the Action of GP63.</a> PLoS Pathogens. 12 (6), 1005690 (2016).</li><li>Dias, B. R. 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=Autophagic+Induction+Greatly+Enhances+Leishmania+major+Intracellular+Survival+Compared+to+Leishmania+amazonensis+in+CBA/j-Infected+Macrophages.">Autophagic Induction Greatly Enhances Leishmania major Intracellular Survival Compared to Leishmania amazonensis in CBA/j-Infected Macrophages.</a> Frontiers in Microbiology. 9, 1890 (2018).</li><li>Babcock, G. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitation+of+phagocytosis+by+confocal+microscopy.">Quantitation of phagocytosis by confocal microscopy.</a> Methods in Enzymology. 307, 319-328 (1999).</li><li>Sanderson, M. J., Smith, I., Parker, I., Bootman, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescence+microscopy.">Fluorescence microscopy.</a> Cold Spring Harbor Protocols. 2014 (10), 071795 (2014).</li><li>Lennartz, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phospholipases+and+phagocytosis:+the+role+of+phospholipid-derived+second+messengers+in+phagocytosis.">Phospholipases and phagocytosis: the role of phospholipid-derived second messengers in phagocytosis.</a> International Journal of Biochemistry &amp; Cell Biology. 31 (3-4), 415-430 (1999).</li><li>Rashidfarrokhi, A., Richina, V., Tafesse, F. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualizing+the+Early+Stages+of+Phagocytosis.">Visualizing the Early Stages of Phagocytosis.</a> Journal of Visualized Experiments. (120), e54646 (2017).</li><li>Ramarao, N., Meyer, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Helicobacter+pylori+resists+phagocytosis+by+macrophages:+quantitative+assessment+by+confocal+microscopy+and+fluorescence-activated+cell+sorting.">Helicobacter pylori resists phagocytosis by macrophages: quantitative assessment by confocal microscopy and fluorescence-activated cell sorting.</a> Infection and Immunity. 69 (4), 2604-2611 (2001).</li><li>Bain, J., Gow, N. A., Erwig, L. 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The funders had no role in study design, data collection or analysis, the decision to publish, or preparation of the manuscript. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Leishmania-macrophage interaction is a complex process and involves several steps that can influence disease development5. To better understand the mechanisms involved in the interaction of unopsonized Leishmania and host cells, we have described a protocol that employs confocal fluorescence microscopy to assess phagocytosis from early to late stages of Leishmania infection. The use of fluorescence techniques involving two or more fluorophores to investigate cell biology...

Leishmaniasis is a neglected tropical disease caused by protozoan parasites of the genus Leishmania, resulting in a broad spectrum of clinical manifestations in the vertebrate host, including cutaneous leishmaniasis, mucocutaneous leishmaniasis and visceral leishmaniasis1.&#160;The World Health Organization (WHO) estimates that over one billion people are at risk, with more than one million new cases reported per year2.
Leishmania spp. are obligate intracellular protozoans that survive inside host cells, including monocytes, macrophages and dendritic cells3. Leishmania-macrophage interaction is a complex process that involves multiple host cell receptors and parasite ligands either through direct interaction or by opsonization involving complement receptors4,5. Classical surface receptors, such as CR1, CR3, mannose-fucose, fibronectin, toll-like and scavenger receptors, mediate parasite attachment to macrophages6,7,8. These receptors recognize molecules on the surface of Leishmania, including the 63 kDa glycoprotein (gp63) and glycolipid lipophosphoglycan (LPG)9. These are the most abundant molecules on the surface of promastigotes and play an essential role in the subversion of host immune response, favoring the establishment of parasite infection in mammalian cells10. After parasite surface ligands bind to macrophage receptors, F-actin accumulates on mammalian cell surfaces, surrounding parasites as they are phagocytosed. Subsequently, this leads to the formation of a parasite-induced compartment termed parasitophorous vacuole (PV), which presents phagolysosomal features11. Once inside these phagolysosomes, parasites undergo several alterations essential to survival and multiplication3.
The biogenesis of PVs is a highly regulated membrane trafficking process critical to the intracellular survival of this pathogen12. The formation of this compartment results from sequential fusion events between phagosomes and compartments of the host endocytic pathway. Classical cell biology studies have revealed that the maturation of PVs involves the acquisition of monomeric G protein Rab 5 and Rab 7 proteins, which are mainly associated with early and late endosome maturation, respectively13. In addition, these compartments acquire lysosome-associated membrane proteins 1 and 2 (LAMP 1, LAMP 2), the principal protein constituents of the lysosomal membrane and microtubule-associated protein 1A/1B-light chain 3 (LC3), an autophagosome marker14. Despite apparent similarities, the kinetics of PV formation15,16 and the morphology of these compartments vary depending on Leishmania species. For example, infection caused by L. mexicana or L. amazonensis induces the formation of large compartments containing a great number of parasites17. By contrast, other species, such as L. braziliensis and L. infantum, form smaller vacuoles that normally contain only one or two parasites in each vacuole18.
Despite this knowledge surrounding host cell-Leishmania interaction, the initial events triggered by contact between host receptors and parasite ligands have not been fully elucidated. These events are known to be determinants of the outcome of parasite infection and are dependent on parasite species, the type of host cell receptors recruited to recognize parasites and the activation of macrophage signaling pathways19,20. Therefore, it is essential to identify the molecules involved in the biogenesis of Leishmania-induced PVs and determine the role(s) played by these molecules in infection establishment and outcome. Here, we describe a method of monitoring early events occurring during the phagocytosis of Leishmania, including binding, internalization, phagosome formation and maturation. This work could aid in clarifying the participation of PLC, Akt, Rab5, Rab7 and LC3 in the formation of PVs induced by different Leishmania species. Importantly, this protocol can be used to investigate the participation of other proteins involved in PV maturation. Future studies will expand the knowledge surrounding mechanisms involved in Leishmania-host cell interaction and contribute to the design of novel chemotherapeutic strategies.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>2-mercaptoethanol</td>
			<td>Thermo Fisher Scientific</td>
			<td>21985023</td>
			<td></td>
		</tr>
		<tr>
			<td>AlexaFluor 488-conjugated goat anti-rabbit IgG</td>
			<td>Thermo Fisher Scientific</td>
			<td>Tem varios no site</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-LC3 antibody</td>
			<td>Novus Biologicals</td>
			<td>NB600-1384</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine serum albumin (BSA)</td>
			<td>Thermo Fisher Scientific</td>
			<td>X</td>
			<td></td>
		</tr>
		<tr>
			<td>CellStripper</td>
			<td>Corning</td>
			<td>25-056-CI</td>
			<td></td>
		</tr>
		<tr>
			<td>CellTracker Red (CMTPX) Dye</td>
			<td>Thermo Fisher Scientific</td>
			<td>C34552</td>
			<td></td>
		</tr>
		<tr>
			<td>Centr&#237;fuga</td>
			<td>Thermo Fisher Scientific</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ciprofloxacin</td>
			<td>Isofarma</td>
			<td>X</td>
			<td></td>
		</tr>
		<tr>
			<td>CO2 incubator</td>
			<td>Thermo Fisher Scientific</td>
			<td>X</td>
			<td></td>
		</tr>
		<tr>
			<td>Confocal fluorescence microscope (Leica SP8)</td>
			<td>Leica</td>
			<td>Leica SP8</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum (FBS)</td>
			<td>Gibco</td>
			<td>10270106</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluorescence microscope (Olympus Lx73)</td>
			<td>Olympus</td>
			<td>Olympus Lx73</td>
			<td></td>
		</tr>
		<tr>
			<td>Gentamicin</td>
			<td>Gibco</td>
			<td>15750045</td>
			<td></td>
		</tr>
		<tr>
			<td>Glutamine</td>
			<td>Thermo Fisher Scientific</td>
			<td>35050-061</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES (N- 2-hydroxyethyl piperazine-N&#8217;-2-ethane-sulfonic acid)</td>
			<td>Gibco</td>
			<td>X</td>
			<td></td>
		</tr>
		<tr>
			<td>Histopaque</td>
			<td>Sigma</td>
			<td>10771</td>
			<td></td>
		</tr>
		<tr>
			<td>M-CSF</td>
			<td>Peprotech</td>
			<td>300-25</td>
			<td></td>
		</tr>
		<tr>
			<td>NH4Cl</td>
			<td>Sigma</td>
			<td>A9434</td>
			<td></td>
		</tr>
		<tr>
			<td>Normal goat serum</td>
			<td>Sigma</td>
			<td>NS02L</td>
			<td></td>
		</tr>
		<tr>
			<td>Nucleofector 2b Device</td>
			<td>Lonza</td>
			<td>AAB-1001</td>
			<td></td>
		</tr>
		<tr>
			<td>Nucleofector solution</td>
			<td>Lonza</td>
			<td>VPA-1007</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Sigma</td>
			<td>158127</td>
			<td></td>
		</tr>
		<tr>
			<td>Phalloidin</td>
			<td>Invitrogen</td>
			<td>A12379</td>
			<td></td>
		</tr>
		<tr>
			<td>Phorbol myristate acetate (PMA)</td>
			<td>Sigma</td>
			<td>P1585</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate buffer solution (PBS)</td>
			<td>Thermo Fisher Scientific</td>
			<td>10010023</td>
			<td></td>
		</tr>
		<tr>
			<td>ProLong Gold Antifade kit</td>
			<td>Life Technologies</td>
			<td>P36931</td>
			<td></td>
		</tr>
		<tr>
			<td>Roswell Park Memorial Institute (RPMI) 1640 medium</td>
			<td>Gibco</td>
			<td>11875-093</td>
			<td></td>
		</tr>
		<tr>
			<td>Saponin</td>
			<td>Thermo Fisher Scientific</td>
			<td>X</td>
			<td></td>
		</tr>
		<tr>
			<td>Schneider&#39;s Insect medium</td>
			<td>Sigma</td>
			<td>S0146</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium bicarbonate</td>
			<td>Sigma</td>
			<td>S5761</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium pyruvate</td>
			<td>Sigma</td>
			<td>S8636</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma</td>
			<td>X</td>
			<td></td>
		</tr>
	</tbody>
</table>

investigating the phagocytosis of leishmania using confocal microscopy

Phagocytosis is an orchestrated process that involves distinct steps: recognition, binding, and internalization. Professional phagocytes take up Leishmania parasites by phagocytosis, consisting of recognizing ligands on parasite surfaces by multiple host cell receptors. Binding of Leishmania to macrophage membranes occurs through complement receptor type 1 (CR1) and complement receptor type 3 (CR3) and Pattern Recognition Receptors. Lipophosphoglycan (LPG) and 63 kDa glycoprotein (gp63) are the main ligands involved in macrophage-Leishmania interactions. Following the initial recognition of parasite ligands by host cell receptors, parasites become internalized, survive, and multiply within parasitophorous vacuoles. The maturation process of Leishmania-induced vacuoles involves the acquisition of molecules from intracellular vesicles, including monomeric G protein Rab 5 and Rab 7, lysosomal associated membrane protein 1 (LAMP-1), lysosomal associated membrane protein 2 (LAMP-2), and microtubule-associated protein 1A/1B-light chain 3 (LC3).
Here, we describe methods to evaluate the early events occurring during Leishmania interaction with the host cells using confocal microscopy, including (i) binding (ii) internalization, and (iii) phagosome maturation. By adding to the body of knowledge surrounding these determinants of infection outcome, we hope to improve the understanding of the pathogenesis of Leishmania infection and support the eventual search for novel chemotherapeutic targets.

This report aims to evaluate the early events occurring during the phagocytosis of L. braziliensis isolated from patients presenting L. braziliensis-LCL or L. braziliensis-DL form of CL. Using confocal microscopy, we investigated the main events associated with parasites&#39; phagocytosis: binding, internalization, and phagosome maturation. We first evaluated the L. braziliensis-LCL or L. braziliensis-DL binding and phagocytosis by human monocyte-derived macrophages. The data ...

Watch this Scientific Journal Video about Investigating the Phagocytosis of Leishmania using Confocal Microscopy at JoVE.com

Investigating the Phagocytosis of Leishmania using Confocal Microscopy

The mechanism associated with phagocytosis in Leishmania infection remains poorly understood. Here, we describe methods to evaluate the early events occurring during Leishmania interaction with the host cells.

Investigating the Phagocytosis of Leishmania using Confocal Microscopy

Phagocytosis is an orchestrated process that involves distinct steps: recognition, binding, and internalization. Professional phagocytes take up ...

The mechanism associated with phagocytosis in Leishmania infection remain poorly understood. Here we describe methods to evaluate the early states of curing during Leishmania interaction to the host cells. This technique presents as the main advantage, allowing the study of different states of Leishmania phagocytosis and the participation of several proteins.It is worth noting that this technique can also be extended to other types of studies, including infection by bacteria, yeasts, or be it engulfment by other types of cells. People trying this technique should take care of the exposure time of the cells to the Nucleofector solution. In addition, we suggest start testing transfection using a maximum of two plasmids.Demonstrating the procedure will be Amanda Reboucas, a PhD student from our laboratory. To begin with, seed 0.2 million THP-1 cells, or human monocyte-derived macrophages in 500 microliters RPMI per well on a 24 well plate with 13 millimeter glass coverslips. Incubate for 24 hours at 37 degrees Celsius under 5%carbon dioxide, wash cells twice with 0.9%saline and incubate the cells in a Complete RPMI Medium.Add stationary phase Leishmania species to the cells at a 10 parasite is to one host cell ratio, and then, centrifuge at 720 times g for 10 minutes at four degrees Celsius. After incubating the cells at four degrees Celsius for five minutes, wash the cells twice with 0.9%saline solution to remove any non-internalized promastigotes. Incubate the cells in supplemented RPMI Medium at 37 degrees Celsius for one hour, and then, fix the cells with 4%PFA for 15 minutes.Next, mount coverslips using preferred mounting media. Then, count at least 400 cells in random fields under a fluorescence microscope. To investigate the Leishmania-induced PV biogenesis, start transfecting THP-1 cells with plasmid by seeding 15 million THP-1 cells in 75 square centimeters tissue culture flasks containing 10 milliliters of Complete RPMI Medium supplemented with 100 nanograms per milliliter PMA, and 50 micromolar to mercaptoethanol for 48 hours.Then, wash the cells once in 0.9%saline solution and detach the cells using a non-enzymatic cell dissociation solution. Then, centrifuge at 250 times g for five minutes at room temperature. Next, resuspend the THP-1 cells in one milliliter of RPMI Medium and perform counts in a Neubauer chamber.Centrifuge the cells again at 250 times g for 10 minutes at room temperature and discard the supernatant. Resuspend 2 million cells in 100 microliters of Nucleofector solution and incubate with 0.5 micrograms of the plasmid coating for the protein of interest, tagged with a fluorescent protein. Transfer the suspension containing THP-1 cells and nucleic acid to the Nucleofector cuvette.Then, transfect the cells using Nucleofector program Y one. Recover the transfected cells and seed in 500 microliters of RPMI Medium on 24 well plates with 13 millimeter glass coverslips. Incubate the cells and Complete RPMI Medium at 37 degrees Celsius for 0.5, 2, 4, 6, 12, and 24 hour.Leave the 13 millimeter glass coverslips at room temperature and protect them from the light at least 30 minutes before the acquisition. Clean the coverslips with absorbent tissue. Next, add a drop of immersion oil to the objective, and then add the slide.Move the objective up until the oil touches the slide. Observe and adjust the focus on the microscope and choose option 63x objective with oil. Open the LIQA program and adjust the lasers in the 488, 552, and 405 wavelengths.Select the image resolution as 1024 x 1024. After clicking on the live button, set the Z-stack and press the begin option. Wait for the image acquisition and then select the option, maximum projection, in the tools.Save the experiment, and export the TIFF format images to a computer. The results showed that both Leishmania Braziliensis LCL, and Leishmania Braziliensis DL, similarly bind to macrophages. Also, no differences were observed regarding Leishmania Braziliensis LCL and Leishmania Braziliensis DL phagocytosis by host cells.The recruitment of LC3 to the parasitophorous vacuole, or PV's, induced by Leishmania Braziliensis LCL or Leishmania Braziliensis DL, was compared in infected cells. After four hours of infection, similar percentages of LC3-decorated PV's in Leishmania Braziliensis LCL and Leishmania Braziliensis DL infected macrophages were observed. Thus, results showed that Leishmania Braziliensis LCL and Leishmania Braziliensis DL similarly interact with macrophages during binding, phagocytosis, and biogenesis of PV's concerning the LC3 recruitment.Representative microscopic images demonstrated efficient transfection of THP-1 cells with PLC-GFP, Rab5-GFP, Rab7-GFP plasmids. People trying this protocol must pay attention to temperature incubation and protect the microscope samples from the light, all the types. Modulating the expression of the identified proteins precipitating Leishmania phagocytosis will demonstrate the importance of those proteins in Leishmania infection outcome.We can extend this technique toward different types of pathology studies and mechanisms associated with parasite establishment and target identification for the development of therapeutic strategies.

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Research

JoVE Journal

Immunology and Infection

2.6K Views.  Gonçalo Moniz Institute. The mechanism associated with phagocytosis in Leishmania infection remain poorly understood. Here we describe methods to evaluate the early states of curing during Leishmania interaction to the host cells. This technique presents as the main advantage, allowing the study of different states of Leishmania phagocytosis and the participation of several proteins.It is worth noting that this technique can also be extended to other types of studies, including infection by bacteria, yeasts, o...