We are particularly grateful to S. Graewe and V. Heussler for the initial training and continuous input in intravital microscopy of malaria parasites, to J. Burns for donating GFP transgenic parasites, to A. Bosch (Confocal Unit, CCiT-UB, IDIBAPS) for assistance in image analysis and quantification and to P. Astola for technical assistance. We thank R. Tous and I. Caralt for video production. MF is a recipient of a graduate fellowship from the Generality of Catalonia. HAP is an ICREA research professor. Work in the laboratory of HAP is funded by the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement N&deg; 242095, by the Private Foundation CELLEX (Catalonia, Spain), and by the Spanish Ministry of Science and Innovation (SAF2009-07760).

This method was used in the research reported in 7.
1. Animal infection with green fluorescent protein (GFP) transgenic parasites 
<ol>
 <li>P. yoelii&#x2013;GFP transgenic lines of 17XL and 17X were generated using the same vectors, targeting strategy and protocols described elsewhere for P. berghei8. They express the mutant 3 variant of GFP 9 under the ubiquitous promoter of P. berghei elongation factor 1 (Pbeef1a), whi...

<ol>
	<li>Amino, R., Menard, R., Frischknecht, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+imaging+of+malaria+parasites--recent+advances+and+future+directions.">In vivo imaging of malaria parasites--recent advances and future directions.</a> Curr. Opin. Microbiol. 8, 407-414 (2005).</li><li>Heussler, V., Doerig, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+imaging+enters+parasitology.">In vivo imaging enters parasitology.</a> Trends. Parasitol. 22, 192-195 (2006).</li><li>Amino, R., Thiberge, S., Blazquez, S., Baldacci, P., Renaud, O., Shorte, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+malaria+sporozoites.">Imaging malaria sporozoites.</a> in the dermis of the mammalian. 2, 1705-1712 (2007).</li><li>Gueirard, P., Tavares, J., Thiberge, S., Bernex, F., Ishino, T., Milon, G. <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+malaria+parasite+in+the+skin+of+the+mammalian+host.">Development of the malaria parasite in the skin of the mammalian host.</a> Proc. Natl. Acad. Sci. U. S. A. 107, 18640-18645 (2010).</li><li>Sturm, A., Amino, R., van de Sand, C., Regen, T., Retzlaff, S., Rennenberg, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Manipulation+of+host+hepatocytes+by+the+malaria+parasite+for+delivery+into+liver+sinusoids.">Manipulation of host hepatocytes by the malaria parasite for delivery into liver sinusoids.</a> Science. 313, 1287-1290 (2006).</li><li>Gruring, C., Heiber, A., Kruse, F., Ungefehr, J., Gilberger, T. W., Spielmann, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+host+cell+modifications+of+Plasmodium+falciparum+blood+stages+in+four+dimensions.">Development and host cell modifications of Plasmodium falciparum blood stages in four dimensions.</a> Nat. Commun. 2, 165-165 (2011).</li><li>Martin-Jaular, L., Ferrer, M., Calvo, M., Rosanas-Urgell, A., Kalko, S., Graewe, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strain-specific+spleen+remodelling+in+Plasmodium+yoelii+infections+in+Balb/c+mice+facilitates+adherence+and+spleen+macrophage-clearance+escape.">Strain-specific spleen remodelling in Plasmodium yoelii infections in Balb/c mice facilitates adherence and spleen macrophage-clearance escape.</a> Cell. Microbiol. 13, 109-122 (2011).</li><li>Linden, M. v. a. n. d. e. r., 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+Plasmodium+berghei+reference+line+that+constitutively+expresses+GFP+at+a+high+level+throughout+the+complete+life+cycle.">A Plasmodium berghei reference line that constitutively expresses GFP at a high level throughout the complete life cycle.</a> Mol. Biochem. Parasitol. 137, 23-33 (2004).</li><li>Cormack, B. P., Valdivia, R. H., Falkow, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FACS-optimized+mutants+of+the+green+fluorescent+protein.">FACS-optimized mutants of the green fluorescent protein.</a> 173, 33-38 (1996).</li><li>Dunn, K. W., Sandoval, R. M., Kelly, K. J., Dagher, P. C., Tanner, G. A., Atkinson, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+studies+of+the+kidney+of+living+animals+using+multicolor+two-photon+microscopy.">Functional studies of the kidney of living animals using multicolor two-photon microscopy.</a> Am. J. Physiol. Cell. Physiol. 283, C905-C916 (2002).</li><li>Zhong, Z., Petrig, B. L., Qi, X., Burns, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+measurement+of+erythrocyte+velocity+and+retinal+blood+flow+using+adaptive+optics+scanning+laser+ophthalmoscopy.">In vivo measurement of erythrocyte velocity and retinal blood flow using adaptive optics scanning laser ophthalmoscopy.</a> Opt. Express. 16, 12746-12756 (2008).</li><li>Miller, M. J., Wei, S. H., Parker, I., Cahalan, 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=Two-photon+imaging+of+lymphocyte+motility+and+antigen+response+in+intact+lymph+node.">Two-photon imaging of lymphocyte motility and antigen response in intact lymph node.</a> Science. 296, 1869-1873 (2002).</li><li>Bowdler, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The complete spleen. , (2002).</li><li>Grayson, M. H., Hotchkiss, R. S., Karl, I. E., Holtzman, M. J., Chaplin, D. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravital+microscopy+comparing+T+lymphocyte+trafficking+to+the+spleen+and+the+mesenteric+lymph+node.">Intravital microscopy comparing T lymphocyte trafficking to the spleen and the mesenteric lymph node.</a> Am. J. Physiol. Heart. Circ. Physiol. 284, H2213-H2226 (2003).</li><li>Khandoga, A. G., Khandoga, A., Reichel, C. A., Bihari, P., Rehberg, M., Krombach, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+imaging+and+quantitative+analysis+of+leukocyte+directional+migration+and+polarization+in+inflamed+tissue.">In vivo imaging and quantitative analysis of leukocyte directional migration and polarization in inflamed tissue.</a> PLoS. One. 4, 4693-4693 (2009).</li><li>Weiss, L., Geduldig, U., Weidanz, W. <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+splenic+control+of+murine+malaria:+reticular+cell+activation+and+the+development+of+a+blood-spleen+barrier.">Mechanisms of splenic control of murine malaria: reticular cell activation and the development of a blood-spleen barrier.</a> Am. J. Anat. 176, 251-285 (1986).</li><li>Swirski, F. K., Nahrendorf, M., Etzrodt, M., Wildgruber, M., Cortez-Retamozo, V., Panizzi, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+splenic+reservoir+monocytes+and+their+deployment+to+inflammatory+sites.">Identification of splenic reservoir monocytes and their deployment to inflammatory sites.</a> Science. 325, 612-616 (2009).</li><li>Grayson, M. H., Chaplin, D. D., Karl, I. E., Hotchkiss, 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=Confocal+fluorescent+intravital+microscopy+of+the+murine+spleen.">Confocal fluorescent intravital microscopy of the murine spleen.</a> J. Immunol. Methods. 256, 55-63 (2001).</li><li>Bajenoff, M., Glaichenhaus, N., Germain, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fibroblastic+reticular+cells+guide+T+lymphocyte+entry+into+and+migration+within+the+splenic+T+cell+zone.">Fibroblastic reticular cells guide T lymphocyte entry into and migration within the splenic T cell zone.</a> J. Immunol. 181, 3947-3954 (2008).</li></ol>

No conflicts of interest declared.

The implementation of intravital microscopy of the spleen in this rodent malaria model opened the possibility of investigating the dynamic passage of parasites through this organ which until now has been considered a "black-box" due to technical considerations. In here, a major effort was put to adapt a quantitative method that allows comparative analysis of different parasite lines at the single and population levels. In contrast to other tissues and cells that had been imaged before in malaria 3,5, imaging ...

<table border="1">
<tbody>
 <tr>
 <td>Name of the reagent</td>
 <td>Company</td>
 <td>Catalogue 	number</td>
 <td>Comments</td>
 </tr>
 <tr>
 <td>Leica 			TCS-SP5 confocal microscope</td>
 <td>Leica 			Microsystems, Heidelberg, Germany</td>
 <td>TCS-SP5 Serial 			no. 5100000419</td>
 <td>&nbsp;
 </td>
 </tr>
 <tr>
 <td>Ketamine 			(Ketolar 50 			mg/ml)</td>
 <td>Pfizer</td>
 <td>631028</td>
 <td>&nbsp;
 </td>
 </tr>
 <tr>
 <td>Midazolam 			15 mg/3 ml</td>
 <td>Normon</td>
 <td>838193</td>
 <td>&nbsp;
 </td>
 </tr>
 <tr>
 <td>70,000 			MW Dextran, conjugated to Texas Red</td>
 <td>Molecular 			Probes</td>
 <td>D1830</td>
 <td>&nbsp;
 </td>
 </tr>
 <tr>
 <td>Fluorescein 			Isothiocyanate, isomer I (FITC)</td>
 <td>Sigma</td>
 <td>F7250</td>
 <td>&nbsp;
 </td>
 </tr>
 <tr>
 <td>Hoechst 			33342</td>
 <td>Sigma</td>
 <td>H1399</td>
 <td>&nbsp;
 </td>
 </tr>
 <tr>
 <td>Giemsa 			stain</td>
 <td>Sigma</td>
 <td>GS1</td>
 <td>Working 			solution is at 10% 			in distilled water</td>
 </tr>
 <tr>
 <td>Super 			Glue-3 Loctite</td>
 <td>Loctite</td>
 <td>9975-0880</td>
 <td>&nbsp;
 </td>
 </tr>
 </tbody>
</table>

intravital microscopy of the spleen: quantitative analysis of parasite mobility and blood flow

The advent of intravital microscopy in experimental rodent malaria models has allowed major advances to the knowledge of parasite-host interactions 1,2. Thus, in vivo imaging of malaria parasites during pre-erythrocytic stages have revealed the active entrance of parasites into skin lymph nodes 3, the complete development of the parasite in the skin 4, and the formation of a hepatocyte-derived merosome to assure migration and release of merozoites into the blood stream 5. Moreover, the development of individual parasites in erythrocytes has been recently documented using 4D imaging and challenged our current view on protein export in malaria 6. Thus, intravital imaging has radically changed our view on key events in Plasmodium development. Unfortunately, studies of the dynamic passage of malaria parasites through the spleen, a major lymphoid organ exquisitely adapted to clear infected red blood cells are lacking due to technical constraints.
Using the murine model of malaria Plasmodium yoelii in Balb/c mice, we have implemented intravital imaging of the spleen and reported a differential remodeling of it and adherence of parasitized red blood cells (pRBCs) to barrier cells of fibroblastic origin in the red pulp during infection with the non-lethal parasite line P.yoelii 17X as opposed to infections with the P.yoelii 17XL lethal parasite line 7. To reach these conclusions, a specific methodology using ImageJ free software was developed to enable characterization of the fast three-dimensional movement of single-pRBCs. Results obtained with this protocol allow determining velocity, directionality and residence time of parasites in the spleen, all parameters addressing adherence in vivo. In addition, we report the methodology for blood flow quantification using intravital microscopy and the use of different colouring agents to gain insight into the complex microcirculatory structure of the spleen. 
Ethics statement
All the animal studies were performed at the animal facilities of University of Barcelona in accordance with guidelines and protocols approved by the Ethics Committee for Animal Experimentation of the University of Barcelona CEEA-UB (Protocol No DMAH: 5429). Female Balb/c mice of 6-8 weeks of age were obtained from Charles River Laboratories.

Watch this Scientific Journal Video about Intravital Microscopy of the Spleen: Quantitative Analysis of Parasite Mobility and Blood Flow at JoVE.com

Intravital Microscopy of the Spleen: Quantitative Analysis of Parasite Mobility and Blood Flow

We show the method for performing intravital microscopy of the spleen using GFP transgenic malaria parasites and the quantification of parasite mobility and blood flow within this organ.

The advent of intravital microscopy in experimental rodent malaria models has allowed major advances to the knowledge of parasite-host interactions 1,2. ...

intravital-microscopy-spleen-quantitative-analysis-parasite-mobility

Research

JoVE Journal

Immunology and Infection

18.0K 조회수.  Barcelona Centre for International Health Research. 우리는 GFP 형질 전환 말라리아 기생충이 장기 내에 기생충의 이동성과 혈액 흐름의 부량를 사용하여 비장의 intravital 현미경을 수행하는 방법을 보여줍니다.