Nous reconnaissons le soutien financier du Conseil national de recherches Santé et paramédical (accorder APP605524, 490037 et 1047082), le Conseil australien de la recherche (subvention DP12010061), la stratégie de l&#39;infrastructure de recherche en collaboration nationale de l&#39;Australie et le fonds d&#39;investissement de l&#39;éducation du ministère de l&#39;Innovation, de l&#39;Industrie , de la science et de la recherche. La LEMP est une récipiendaire d&#39;un prix Postgraduate australien.

Toutes les procédures ont été menées en conformité avec les politiques de l&#39;Université Macquarie et conformes au Conseil national de la santé et de la recherche médicale (NHMRC) Code australien de pratique. Le travail a été effectué en vertu de l&#39;éthique de la convention n ° 2012/017 ARA approuvé et obtenu du comité d&#39;éthique animale à l&#39;Université Macquarie. Toutes les expériences ont été réalisées sur des souris SJL / J, sauf indication contraire. 1. Souris et expérimentale paludisme Infection <ol><li> Souris maison sous température contrôlée (21 ° C) avec un cycle lumière-obscurité de 12:12 h. </li><li> Décongeler une aliquote de cryoconservés P. chabaudi adami DS avec 5% (globules rouges parasités culot globulaire) et injecter 200 pi dans la cavité intrapéritonéale de C57BL / 6 donateurs souris. </li><li> Surveiller donateurs parasitémie de souris tous les 1-2 jours en utilisant la cytométrie de flux comme décrit au paragraphe 3-4 de ce protocole. Une fois que les donateurs atteint 5 à 15% de parasitémie, recueillir le sang par ponction cardiaque comme suit: <ol><li>Aspirer 100 pl de solution d&#39;héparine (300 U / ml d&#39;héparine dans une solution souris assortie (MTR) (NaCl 154 mM, KCl 5,6, 1 mM de MgCl2, 2,2 mM de CaCl2, 20 mM de HEPES, 10 mM de glucose, 30 U / ml l&#39;héparine, pH 7,4, 0,22 uM de filtre stérilisé)) dans une seringue de 1 ml avec une aiguille 26 G. </li><li> Anesthésier la souris par inhalation avec 5% isofluorane, confirmant la profondeur désirée de l&#39;anesthésie par l&#39;absence de réponse de retrait de la pédale et les réflexes de la cornée. </li><li> Placez la souris sur le côté et l&#39;aiguille d&#39;insertion perpendiculairement juste en dessous du coude, à travers les côtes, et dans le cœur. Tirez piston de la seringue lentement et tourner aiguille jusqu&#39;à 0,5 à 1 ml de sang est obtenu. </li><li> Effectuer euthanasie par dislocation cervicale sous anesthésie. </li></ol></li><li> Calculer les pRBCs par volume de sang du donneur en supposant une numération formule sanguine de 9 x 10 6 RBC / pi (par exemple, si le donneur était à 10% de parasitémie lors du sacrifice, le sang contient 9 x 10 5pRBC / ul). Diluer sang parasité dans Krebs saline (NaCl 126 mM, KCl 2,5, 25 mM NaHCO3, 1,2 mM de NaH 2 PO 4, 1,2 mM de MgCl2, 2,5 mM de CaCl2, 0,2% de glucose, pH 7,2, 0,22 filtre uM stérilisé) tamponnée de sorte que la concentration est de 1 x 10 4 pRBCs par 200 ul et 200 ul d&#39;injecter dans la cavité intraperitoneale de souris nécessaires à l&#39;étiquetage et RBC expérience de transfusion. </li><li> Surveiller parasitémie tous les 1-2 jours en utilisant la cytométrie de flux comme décrit dans les sections 3-4 de ce protocole. </li></ol> 2. L&#39;étiquetage des globules rouges et transfusion <ol><li> Prélever le sang héparine de souris par ponction cardiaque comme décrit dans l&#39;étape 1.3, et le placer sur la glace. Gardez le sang à 4 ° C en tout temps. Recueillir environ 200 ul de sang par souris à injecter. Si nécessaire, diviser en deux échantillons de sang et traiter un échantillon comme vous le souhaitez. NOTE: De cette façon, l&#39;invasion de la samp traitéle peut être comparée à un contrôle, échantillon non traité (voir la figure 1 pour le schéma). </li><li> Préparer une solution 2x de chaque étiquette de RBC fluorescent. <ol><li> Diluer un ml de solution 2 mg / stock d&#39;Atto 633-N-hydroxysuccinimide (633 Atto-NHS) MTR sorte que la concentration est de 20 ug / ml. </li><li> Diluer un ml solution à 25 mg / ml de biotine-N-hydroxysuccinimide (biotine-NHS) MTR sorte que la concentration est de 250 pg / ml. </li></ol></li><li> Diviser les échantillons de sang en deux tubes et ajouter un volume égal de solution 633 2x Atto-NHS à un tube, et un volume égal de 2x le biotine-NHS à l&#39;autre tube. Mélanger immédiatement. Incuber le sang à 4 ° C pendant 1 heure avec un mélange constant lente, ou encore, l&#39;échantillon mélanger tous les 10 à 15 min. </li><li> Laver 3 fois sang marqués avec MTRC (MTR + 0,5% albumine de sérum bovin (BSA), 0,22 uM de filtre stérilisé) comme suit: <ol><li> Ajouter au moins deux volumes de MTRC, centrifuger à 750 g pendant 5 min, retirer le surnageant, et resuspenD le culot dans au moins deux volumes de MTRC. Répétez deux fois plus. </li><li> Après le lavage final, centrifuger à 750 g pendant 5 min et de combiner le sang granulés dans des combinaisons différentes (ce est à dire, non traitée Atto 633 / biotine traités, non traités biotine / traité Atto 633). Ajouter MTR de faire jusqu&#39;à un volume de 200 ul par souris à injecter. </li></ol></li><li> Injecter du sang marqué par voie intravasculaire dans des souris infectées murins ou témoins non infectés comme suit: <ol><li> Effectuer une transfusion à 2-15% de parasitémie au sommet de parasite schizogonie. REMARQUE: cela se produit à mi-chemin à travers le cycle d&#39;obscurité (ce est à dire, entre 12 à 2 heures du matin un cycle de lumière normale, ou 12-2 h un cycle de feu de recul). </li><li> Souris chaude en utilisant une lampe chauffante pendant 5-10 minutes pour augmenter le flux sanguin, mais de prendre des précautions pour ne pas surchauffer les souris. Placez la souris dans un dispositif de retenue et injecter par voie intravasculaire 200 pi de sang marqué (environ 1-2 x 10 9 RBCs) via la veine caudale. </li></ol></li><li> Prélever des échantillons de sang à différents points de temps après l&#39;injection comme décrit dans la section 3. REMARQUE: les taux d&#39;invasion peuvent être quantifiés moins de 10 minutes après l&#39;injection, en fonction de la parasitémie de la souris receveuse. </li></ol> 3. Prélèvement des échantillons de sang et préparation pour cytométrie en flux <ol><li> Préparer 50 ul de solution de coloration par échantillon, et un peu plus, le jour de l&#39;expérience comme suit: <ol><li> Décongeler une aliquote de 6 mM de JC-1 stockée à -20 ° C dans du diméthylsulfoxyde (DMSO). </li><li> Chaud 50 pi de MTRC par échantillon, et un peu plus, à 37 ° C. </li><li> Alors que le vortex continu MTRC préchauffée, ajouter JC-1 de sorte que la concentration finale est de 12 pM. Ceci est fait pour réduire la formation de JC-1 agrégats; si agrégats ne forment, faire le tube centrifugeuse pas que cela permettra d&#39;éviter la coloration. NOTE: Une petite quantité d&#39;agrégation ne affectera pas les résultats. </li><li> Ajouter anti-CD45 APC eFluor 780 et anti-CD71 PerCP eFluor 710 de sorte que la concentration finale soit de 1 ug / ml. Si l&#39;exécution de l&#39;expérience RBC marqué, ajouter de la streptavidine PE-Cy7 de sorte que la concentration finale soit de 1 ug / ml. </li></ol></li><li> Effectuer queue saignements par l&#39;amputation de l&#39;extrémité de la queue ou de lacération du vaisseau sanguin dans la queue. Placez une goutte de sang de la queue sur un petit bateau ou peser lame de verre. Après la collecte de sang, se assurer que le saignement se est arrêté. Pipette 3 ul de sang de la queue dans 50 ul de solution de coloration pré-chauffé à 37 ° C et incuber les échantillons à 37 ° C pendant 20 min. </li><li> Décongeler une aliquote de 4 mM de Hoechst 33342 stocké à -20 ° C dans l&#39;eau distillée (si l&#39;on utilise un laser de 355 nm) ou 2 mM de Hoechst 34580 stocké à -20 ° C dans l&#39;eau distillée (si l&#39;on utilise un laser à 405 nm). Préparer 500 ul par échantillon, et un peu plus, d&#39;une solution 4 uM ou 2 M de Hoechst dans MTRC, respectivement. </li><li> Ajouter 500 ul de 4 um Hoechst33 342 2 uM ou Hoechst 34580 à échantillons et incuber à température ambiante pendant 20 min. </li><li> Centrifuger les cellules à 750 g pendant 3 min à 4 ° C, surnageant défausse, ajouter 700 ul MTRC et analysent par cytométrie de flux. </li></ol> 4. cytométrie en flux <ol><li> Analyser des échantillons en utilisant un laser 355/488/633 nm ou 405/488/633 instrument laser nm. </li><li> Filtrer les échantillons à travers un tamis cellulaire immédiatement 35 uM avant l&#39;analyse. Rincer la crépine de la cellule avec de l&#39;eau distillée entre les échantillons et réutilisation. </li><li> Enregistrer suffisamment d&#39;événements de telle sorte que la plus petite population contient au moins 500 événements (généralement 1.000.000 - 10.000.000 événements totales par échantillon). </li><li> Exciter Hoechst 33342 en utilisant un laser de 355 nm et détecter des événements par l&#39;intermédiaire d&#39;un filtre à 460/50. Exciter Hoechst 34580 en utilisant un laser de 405 nm et détecter des événements par l&#39;intermédiaire d&#39;un filtre à 460/50. Excite JC-1, anti-CD71 PerCP eFluor 710 et Streptavidin PE-Cy7 utilisant un laser de 488 nm et détecter des événements à travers un 530/40, 692/40 et 750LP filtre respectifLy. Exciter Atto 633 et anti-CD45 APC eFluor 780 en utilisant un laser de 633 nm et détecter des événements par l&#39;intermédiaire d&#39;un filtre à 670/30 ou 750LP respectivement. </li><li> Effectuer l&#39;analyse et la rémunération en utilisant la cytométrie en flux approprié logiciel d&#39;analyse comme suit: <ol><li> Sélectionnez les cellules entières et d&#39;exclure le bruit, les débris et les plaquettes basé sur FSC / Propriétés SSC (figure 2A). Sélectionner des cellules individuelles sur la base de chaque largeur d&#39;impulsion de déclenchement (figure 2B) ou en utilisant la surface du pic à FSC rapport de hauteur (figure 2C). </li><li> Sélectionnez globules rouges matures, et d&#39;exclure les progéniteurs et les leucocytes RBC, basées sur la fluorescence négative dans les PerCP eFluor 710 et APC eFluor 780 canaux (Figure 2D). </li><li> Si l&#39;exécution de l&#39;expérience RBC marqué, sélectionner chaque population de globules rouges marqués sur la base de PE-Cy7 et Atto 633 fluorescence et les analyser séparément (figure 3A). </li><li> Sélectionnez pRBCs basée sur la fluorescence positive tant pour JC-1 et Hoechst ( <strong&gt; Figure 2E-H). </li></ol></li></ol> 5. Calculs et statistiques <ol><li> Calculer la parasitémie en divisant le nombre de culot globulaire par le nombre total de globules rouges (ce est à dire, nombre d&#39;événements dans la porte Q2 divisé par le nombre d&#39;événements dans la porte G4). Lors de la réalisation de la parasitémie de dosage d&#39;invasion des deux populations marquées peut être calculé en divisant le nombre de culot globulaire marqués par le nombre de globules rouges marqués dans cette population (nombre d&#39;événements qui sont dans les deux portes L1 et Q2, divisé par le nombre d&#39;événements dans la porte L1). REMARQUE: Marqué parasitémie varie considérablement en fonction de facteurs tels que la parasitémie endogène et nombre de mérozoïtes circulation. Pour cette raison, il est utile de signaler le taux de parasitémie, qui est calculé comme la parasitémie de la population marquée traité divisé par la parasitémie de la population contrôle de souris marqué à chaque individu. Pour corriger les effets possibles de colorants, rendre compte des résultats d&#39;uns un rapport de la parasitémie moyenne dans les deux combinaisons de colorants. </li><li> Déterminer la signification statistique des ratios utilisant le t -test d&#39;un échantillon avec une comme la moyenne hypothétique. </li></ol>

<ol>
	<li>Jacobberger, J. W., Horan, P. K., Hare, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+malaria+parasite-infected+blood+by+flow+cytometry.">Analysis of malaria parasite-infected blood by flow cytometry.</a> Cytometry. 4 (3), 228-237 (1983).</li><li>Bianco, A. E., Battye, F. L., Brown, G. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasmodium+falciparum:+rapid+quantification+of+parasitemia+in+fixed+malaria+cultures+by+flow+cytometry.">Plasmodium falciparum: rapid quantification of parasitemia in fixed malaria cultures by flow cytometry.</a> Exp Parasitol. 62 (2), 275-282 (1986).</li><li>Makler, M. T., Lee, L. G., Recktenwald, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thiazole+orange:+a+new+dye+for+Plasmodium+species+analysis.">Thiazole orange: a new dye for Plasmodium species analysis.</a> Cytometry. 8 (6), 568-570 (1987).</li><li>Heyde, H. C., Elloso, M. M., van de Waa, J., Schell, K., Weidanz, W. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+hydroethidine+and+flow+cytometry+to+assess+the+effects+of+leukocytes+on+the+malarial+parasite+Plasmodium+falciparum.">Use of hydroethidine and flow cytometry to assess the effects of leukocytes on the malarial parasite Plasmodium falciparum.</a> Clin Diagn Lab Immunol. 2 (4), 417-425 (1995).</li><li>Pattanapanyasat, 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=Culture+of+malaria+parasites+in+two+different+red+blood+cell+populations+using+biotin+and+flow+cytometry.">Culture of malaria parasites in two different red blood cell populations using biotin and flow cytometry.</a> Cytometry. 25 (3), 287-294 (1996).</li><li>Grimberg, B. T., Erickson, J. J., Sramkoski, R. M., Jacobberger, J. W., Zimmerman, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monitoring+Plasmodium+falciparum+growth+and+development+by+UV+flow+cytometry+using+an+optimized+Hoechst-thiazole+orange+staining+strategy.">Monitoring Plasmodium falciparum growth and development by UV flow cytometry using an optimized Hoechst-thiazole orange staining strategy.</a> Cytometry A. 73 (6), 546-554 (2008).</li><li>Theron, M., Hesketh, R. L., Subramanian, S., Rayner, 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=An+adaptable+two-color+flow+cytometric+assay+to+quantitate+the+invasion+of+erythrocytes+by+Plasmodium+falciparum+parasites.">An adaptable two-color flow cytometric assay to quantitate the invasion of erythrocytes by Plasmodium falciparum parasites.</a> Cytometry A. 77 (11), 1067-1074 (2010).</li><li>Bei, A. 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=A+flow+cytometry-based+assay+for+measuring+invasion+of+red+blood+cells+by+Plasmodium+falciparum.">A flow cytometry-based assay for measuring invasion of red blood cells by Plasmodium falciparum.</a> Am J Hematol. 85 (4), 234-237 (2010).</li><li>Clark, M. 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=RBC+barcoding+allows+for+the+study+of+erythrocyte+population+dynamics+and+P.+falciparum+merozoite+invasion.">RBC barcoding allows for the study of erythrocyte population dynamics and P. falciparum merozoite invasion.</a> PLoS One. 9 (7), e101041 (2014).</li><li>Malleret, 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=A+rapid+and+robust+tri-color+flow+cytometry+assay+for+monitoring+malaria+parasite+development.">A rapid and robust tri-color flow cytometry assay for monitoring malaria parasite development.</a> Sci Rep. 1 (118), (2011).</li><li>Jimenez-Diaz, M. 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=Quantitative+measurement+of+Plasmodium-infected+erythrocytes+in+murine+models+of+malaria+by+flow+cytometry+using+bidimensional+assessment+of+SYTO-16+fluorescence.">Quantitative measurement of Plasmodium-infected erythrocytes in murine models of malaria by flow cytometry using bidimensional assessment of SYTO-16 fluorescence.</a> Cytometry A. 75 (3), 225-235 (2009).</li><li>Jimenez-Diaz, M. 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=Improvement+of+detection+specificity+of+Plasmodium-infected+murine+erythrocytes+by+flow+cytometry+using+autofluorescence+and+YOYO-1.">Improvement of detection specificity of Plasmodium-infected murine erythrocytes by flow cytometry using autofluorescence and YOYO-1.</a> Cytometry A. 67 (1), 27-36 (2005).</li><li>Jun, G., Lee, J. S., Jung, Y. J., Park, 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=Quantitative+determination+of+Plasmodium+parasitemia+by+flow+cytometry+and+microscopy.">Quantitative determination of Plasmodium parasitemia by flow cytometry and microscopy.</a> J Korean Med Sci. 27 (10), 1137-1142 (2012).</li><li>Lelliott, P. M., Lampkin, S., McMorran, B. J., Foote, S. J., Burgio, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+flow+cytometric+assay+to+quantify+invasion+of+red+blood+cells+by+rodent+Plasmodium+parasites+in+vivo.">A flow cytometric assay to quantify invasion of red blood cells by rodent Plasmodium parasites in vivo.</a> Malar J. 13 (1), 100 (2014).</li><li>Morohashi, 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=Structural+and+functional+abnormalities+in+the+spleen+of+an+mFtz-F1+gene-disrupted+mouse.">Structural and functional abnormalities in the spleen of an mFtz-F1 gene-disrupted mouse.</a> Blood. 93 (5), 1586-1594 (1999).</li><li>Shet, A. 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=Morphological+and+functional+platelet+abnormalities+in+Berkeley+sickle+cell+mice.">Morphological and functional platelet abnormalities in Berkeley sickle cell mice.</a> Blood Cells Mol Dis. 41 (1), 109-118 (2008).</li><li>Duraisingh, M. 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=Phenotypic+variation+of+Plasmodium+falciparum+merozoite+proteins+directs+receptor+targeting+for+invasion+of+human+erythrocytes.">Phenotypic variation of Plasmodium falciparum merozoite proteins directs receptor targeting for invasion of human erythrocytes.</a> EMBO J. 22 (5), 1047-1057 (2003).</li><li>Okoyeh, J. N., Pillai, C. R., Chitnis, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasmodium+falciparum+field+isolates+commonly+use+erythrocyte+invasion+pathways+that+are+independent+of+sialic+acid+residues+of+glycophorin+A.">Plasmodium falciparum field isolates commonly use erythrocyte invasion pathways that are independent of sialic acid residues of glycophorin A.</a> Infect Immun. 67 (11), 5784-5791 (1999).</li><li>Dolan, S. A., Miller, L. H., Wellems, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+for+a+switching+mechanism+in+the+invasion+of+erythrocytes+by+Plasmodium+falciparum.">Evidence for a switching mechanism in the invasion of erythrocytes by Plasmodium falciparum.</a> J Clin Invest. 86 (2), 618-624 (1990).</li></ol>

Les auteurs ne ont rien à divulguer.

Nous avons décrit un procédé pour la mesure à la fois de la parasitémie et mérozoïte invasion d&#39;échantillons in vivo. En termes de mesure de la parasitémie, cette méthode offre un avantage par rapport aux méthodes précédentes de 10 à 13 dans ce HJ-globules rouges peut être distinguée de pRBCs, réduisant ainsi le nombre d&#39;événements de faux positifs. Alors que HJ-globules rouges sont généralement rare chez les humains, certaines études rapportent des niveaux élevés chez...

The clinical symptoms associated with malaria occur during the Plasmodium parasite&#8217;s asexual replicative cycle within red blood cells (RBCs). Merozoites, released during the liver stage of infection, quickly attach to and invade RBCs. After gaining entry into the cell, the parasite grows and matures, eventually undergoing schizogony, splitting open the cell, and releasing a cluster of newly formed merozoites which go on to repeat this cycle. As such, an assessment of malaria infection often involves monitoring both parasitemia, which is the percentage of RBCs appropriated by one or more parasites, and the rate of merozoite invasion into uninfected RBCs. 
Flow cytometry is a powerful tool which can be used to record the properties of vast numbers of cells in a short period of time. This technique has clear applicability for the measurement of malaria parasitemia and invasion, and offers several advantages over traditional microscopy techniques. These include the accurate measurement of very low parasitemia, which would be prohibitively time consuming by microscopy, the unbiased nature of the measurement, and the ability to measure multiple cell parameters simultaneously. Flow cytometry is widely used to determine both parasitemia and merozoite invasion in in vitro culture1-9, however, techniques for measuring these parameters in vivo are less well developed, and can be complicated by the presence of additional cell types which interfere with analysis. No assays have been described for measurement of in vivo invasion, and while some assays exist for the analysis of in vivo parasitemia, these lack the ability to distinguish between parasitized RBCs (pRBCs) and RBCs containing Howell-Jolly bodies (HJ-RBCs)10-13. The later issue is particularly important as in mice HJ-RBCs may account for up to 0.9% of mature RBCs14-16, thereby preventing the accurate measurement of low parasitemia. 
We have previously demonstrated an approach for the measurement of parasitemia and merozoite invasion in a rodent model of malaria infection14. Here, we provide a more detailed protocol and accompanying video. This approach builds on previous methodologies and allows for the accurate identification of parasitized RBCs, as distinct from leukocytes, RBC progenitors, and HJ-RBCs. Additionally, this assay allows the simultaneous measurement of merozoite invasion into two labeled RBC populations, a treated, or target, population, and a control population, thereby providing a robust platform for the assessment of invasion into different cell types.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>bisBenzimide H 33342 trihydrochloride</td>
			<td>Sigma-Aldrich</td>
			<td>B2261</td>
			<td>Hoechst 33342. Store a 4mM stock solution at -20 &#176;C in distilled water</td>
		</tr>
		<tr>
			<td>Hoechst 34580</td>
			<td>Sigma-Aldrich</td>
			<td>63493</td>
			<td>Store a 2mM stock solution at -20 &#176;C in distilled water</td>
		</tr>
		<tr>
			<td>JC-1 Dye</td>
			<td>Life Technologies</td>
			<td>T-3168</td>
			<td>Store small aliquots of 6mM stock solution at -20 &#176;C in DMSO</td>
		</tr>
		<tr>
			<td>Anti-Mouse CD45 APC-eFluor 780</td>
			<td>eBioscience</td>
			<td>47-0451-80</td>
			<td>Clone 30-F11</td>
		</tr>
		<tr>
			<td>Anti-Mouse CD71 PerCP-eFluor 710</td>
			<td>eBioscience</td>
			<td>46-0711-80</td>
			<td>Clone R17217</td>
		</tr>
		<tr>
			<td>Atto 633 NHS ester</td>
			<td>Sigma-Aldrich</td>
			<td>1464</td>
			<td>Atto 633-NHS. Store a 2mg/ml stock solution at -20 &#176;C in DMF</td>
		</tr>
		<tr>
			<td>EZ-Link Sulfo-NHS-LC-Biotin</td>
			<td>Thermo Fisher Scientific</td>
			<td>21335</td>
			<td>Biotin-NHS. Store a 25mg/ml stock solution at -20 &#176;C in DMF</td>
		</tr>
		<tr>
			<td>Streptavidin PE-Cyanine7</td>
			<td>eBioscience</td>
			<td>25-4317-82</td>
			<td>Streptavidin PE-Cy7</td>
		</tr>
		<tr>
			<td>Heparin</td>
			<td>Sigma-Aldrich</td>
			<td>H478</td>
			<td></td>
		</tr>
		<tr>
			<td>35&#181;M filter cap tubes</td>
			<td>Becton Dickinson</td>
			<td>352235</td>
			<td></td>
		</tr>
		<tr>
			<td>Flow cytometer: BD LSRFortessa</td>
			<td>Becton Dickinson</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Flow cytometer: BD FACSAria II</td>
			<td>Becton Dickinson</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Flow cytometer: BD Influx</td>
			<td>Becton Dickinson</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Flow cytometer: CyAn ADP Analyzer</td>
			<td>Beckman Coulter</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

in vivo assessment of rodent plasmodium parasitemia and merozoite invasion by flow cytometry

During blood stage infection, malaria parasites invade, mature, and replicate within red blood cells (RBCs). This results in a regular growth cycle and an exponential increase in the proportion of malaria infected RBCs, known as parasitemia. We describe a flow cytometry based protocol which utilizes a combination of the DNA dye Hoechst, and the mitochondrial membrane potential dye, JC-1, to identify RBCs which contain parasites and therefore the parasitemia, of in vivo blood samples from Plasmodium chabaudi adami DS infected mice. Using this approach, in combination with fluorescently conjugated antibodies, parasitized RBCs can be distinguished from leukocytes, RBC progenitors, and RBCs containing Howell-Jolly bodies (HJ-RBCs), with a limit of detection of 0.007% parasitemia. Additionally, we outline a method for the comparative assessment of merozoite invasion into two different RBC populations. In this assay RBCs, labeled with two distinct compounds identifiable by flow cytometry, are transfused into infected mice. The relative rate of invasion into the two populations can then be assessed by flow cytometry based on the proportion of parasitized RBCs in each population over time. This combined approach allows the accurate measurement of both parasitemia and merozoite invasion in an in vivo model of malaria infection.

Mesure de la parasitémie. Pour la mesure de la parasitémie, cellules de sang doivent d&#39;abord être sélectionnés, et le bruit, les débris et les plaquettes exclus, basée sur FSC / SSC propriétés (figure 2A). Selon le cytomètre utilisé, les cellules individuelles doivent alors être sélectionnés en fonction de chaque largeur d&#39;impulsion de déclenchement (figure 2B), ou FSC hauteur de crête à rapport de surface (figure 2C). ...

Watch this Scientific Journal Video about In Vivo Assessment of Rodent Plasmodium Parasitemia and Merozoite Invasion by Flow Cytometry at JoVE.com

In Vivo Assessment of Rodent Plasmodium Parasitemia and Merozoite Invasion by Flow Cytometry

Les envahit de parasites du paludisme et répétitions dans les globules rouges. L&#39;évaluation précise de l&#39;invasion des mérozoïtes et la parasitémie est donc crucial pour évaluer l&#39;évolution de l&#39;infection du paludisme. Nous décrivons ici un protocole basé sur la cytométrie en flux pour la mesure de ces paramètres dans un modèle de souris de la malaria.

Dans l&#39;évaluation in vivo de rongeurs Plasmodium Parasitémie et Merozoite Invasion par cytométrie en flux

During blood stage infection, malaria parasites invade, mature, and replicate within red blood cells (RBCs). This results in a regular growth cycle and an ...

in-vivo-assessment-rodent-plasmodium-parasitemia-merozoite-invasion

Research

JoVE Journal

Immunology and Infection

In Vivo Assessment of Rodent Plasmodium Parasitemia and Merozoite Invasion by Flow Cytometry

9.5K vues.  Macquarie University.  Les envahit de parasites du paludisme et répétitions dans les globules rouges. L'évaluation précise de l'invasion des mérozoïtes et la parasitémie est donc crucial pour évaluer l'évolution de l'infection du paludisme. Nous décrivons ici un protocole basé sur la cytométrie en flux pour la mesure de ces paramètres dans un modèle de souris de la malaria. 

Vidéo: In Vivo Assessment of Rodent Plasmodium Parasitemia and Merozoite Invasion by Flow Cytometry

Measuring Calpain Activity in Fixed and Living Cells by Flow Cytometry

Calpains are ubiquitous intracellular, calcium-sensitive, neutral cysteine proteases 1. Calpains play crucial roles in many physiological processes, including signaling, cytoskeletal remodeling, regulation of gene expression, apoptosis and cell cycle progression 1. Calpains have been implicated in many pathologies including muscular dystrophies, cancer, diabetes, Alzheimer's disease and multiple sclerosis 1. Calpain regulation is complex and incompletely understood. mRNA and protein levels correlate poorly with activity, limiting the use of gene or protein expression techniques to measure calpain activity. This video protocol details a flow cytometric assay developed in our laboratory for measuring calpain activity in fixed and living cells. This method uses the fluorescent substrate BOC-LM-CMAC, which is cleaved specifically by calpain, to measure calpain activity. 2 In this video, calpain activity in fixed and living murine 32Dkit leukemia cells, alone or as part of a splenocyte population is measured using an LSRII (BD Bioscience). 32Dkit cells are shown to have elevated activity compared to normal splenocytes.

This article will detail the protocol for measuring calpain activity in fixed and living cells using flow cytometry.

Mesure de l&#39;activité calpaïne dans des cellules fixées et de la Vie par cytométrie en flux

Calpains are ubiquitous intracellular, calcium-sensitive, neutral cysteine proteases 1. Calpains play crucial roles in many physiological processes, ...

Recherche

Immunologie et infection

Quantitative Assessment of Immune Cells in the Injured Spinal Cord Tissue by Flow Cytometry:  a Novel Use for a Cell Purification Method

Detection of immune cells in the injured central nervous system (CNS) using morphological or histological techniques has not always provided true quantitative analysis of cellular inflammation. Flow cytometry is a quick alternative method to quantify immune cells in the injured brain or spinal cord tissue. Historically, flow cytometry has been used to quantify immune cells collected from blood or dissociated spleen or thymus, and only a few studies have attempted to quantify immune cells in the injured spinal cord by flow cytometry using fresh dissociated cord tissue. However, the dissociated spinal cord tissue is concentrated with myelin debris that can be mistaken for cells and reduce cell count reliability obtained by the flow cytometer. We have advanced a cell preparation method using the OptiPrep gradient system to effectively separate lipid/myelin debris from cells, providing sensitive and reliable quantifications of cellular inflammation in the injured spinal cord by flow cytometry. As described in our recent study (Beck &amp; Nguyen et al., Brain. 2010 Feb; 133 (Pt 2): 433-47), the OptiPrep cell preparation had increased sensitivity to detect cellular inflammation in the injured spinal cord, with counts of specific cell types correlating with injury severity. Critically, novel usage of this method provided the first characterization of acute and chronic cellular inflammation after SCI to include a complete time course for polymorphonuclear leukocytes (PMNs, neutrophils), macrophages/microglia, and T-cells over a period ranging from 2 hours to 180 days post-injury (dpi), identifying a surprising novel second phase of cellular inflammation. Thorough characterization of cellular inflammation using this method may provide a better understanding of neuroinflammation in the injured CNS, and reveal an important multiphasic component of neuroinflammation that may be critical for the design and implementation of rational therapeutic treatment strategies, including both cell-based and pharmacological interventions for SCI.

Quantification of cellular inflammation in the injured/pathological CNS by flow cytometry is complicated by lipid/myelin debris that can have similar size and granulation to cells, decreasing sensitivity/accuracy. We have advanced a cell preparation method to remove myelin debris and improve cell detection by flow cytometry in the injured spinal cord.

Évaluation quantitative des cellules immunitaires dans le tissu blessés médullaires par cytométrie en flux: une nouvelle utilisation pour un procédé de purification cellulaire

Detection of immune cells in the injured central nervous system (CNS) using morphological or histological techniques has not always provided true ...

Human In Vitro Suppression as Screening Tool for the Recognition of an Early State of Immune Imbalance

Regulatory T cells (Tregs) are critical mediators of immune tolerance to self-antigens. In addition, they are crucial regulators of the immune response following an infection. Despite efforts to identify unique surface marker on Tregs, the only unique feature is their ability to suppress the proliferation and function of effector T cells. While it is clear that only in vitro assays can be used in assessing human Treg function, this becomes problematic when assessing the results from cross-sectional studies where healthy cells and cells isolated from subjects with autoimmune diseases (like Type 1 Diabetes-T1D) need to be compared. There is a great variability among laboratories in the number and type of responder T cells, nature and strength of stimulation, Treg:responder ratios and the number and type of antigen-presenting cells (APC) used in human in vitro suppression assays. This variability makes comparison between studies measuring Treg function difficult. The Treg field needs a standardized suppression assay that will work well with both healthy subjects and those with autoimmune diseases. We have developed an in vitro suppression assay that shows very little intra-assay variability in the stimulation of T cells isolated from healthy volunteers compared to subjects with underlying autoimmune destruction of pancreatic &beta;-cells. The main goal of this piece is to describe an in vitro human suppression assay that allows comparison between different subject groups. Additionally, this assay has the potential to delineate a small loss in nTreg function and anticipate further loss in the future, thus identifying subjects who could benefit from preventive immunomodulatory therapy1. Below, we provide thorough description of the steps involved in this procedure. We hope to contribute to the standardization of the in vitro suppression assay used to measure Treg function. In addition, we offer this assay as a tool to recognize an early state of immune imbalance and a potential functional biomarker for T1D.

Human In Vitro Suppression as Screening Tool for the Recognition of an Early State of Immune Imbalance

Tregs are potent suppressors of the immune system. There is a lack of unique surface markers to define them, hence, definitions of Tregs are primarily functional. Here we describe an optimized in vitro assay capable of identifying immune imbalance in subjects at risk to develop T1D.

Homme In Vitro</emRépression> comme outil de dépistage pour la reconnaissance d&#39;un Etat précoce de déséquilibre immunitaire

Regulatory T cells (Tregs) are critical mediators of immune tolerance to self-antigens. In addition, they are crucial regulators of the immune response ...

Examination of Thymic Positive and Negative Selection by Flow Cytometry

A healthy immune system requires that T cells respond to foreign antigens while remaining tolerant to self-antigens. Random rearrangement of the T cell receptor (TCR) &alpha; and &beta; loci generates a T cell repertoire with vast diversity in antigen specificity, both to self and foreign. Selection of the repertoire during development in the thymus is critical for generating safe and useful T cells. Defects in thymic selection contribute to the development of autoimmune and immunodeficiency disorders1-4. 
T cell progenitors enter the thymus as double negative (DN) thymocytes that do not express CD4 or CD8 co-receptors. Expression of the &alpha;&beta;TCR and both co-receptors occurs at the double positive (DP) stage. Interaction of the &alpha;&beta;TCR with self-peptide-MHC (pMHC) presented by thymic cells determines the fate of the DP thymocyte. High affinity interactions lead to negative selection and elimination of self-reactive thymocytes. Low affinity interactions result in positive selection and development of CD4 or CD8 single positive (SP) T cells capable of recognizing foreign antigens presented by self-MHC5.
Positive selection can be studied in mice with a polyclonal (wildtype) TCR repertoire by observing the generation of mature T cells. However, they are not ideal for the study of negative selection, which involves deletion of small antigen-specific populations. Many model systems have been used to study negative selection but vary in their ability to recapitulate physiological events6. For example, in vitro stimulation of thymocytes lacks the thymic environment that is intimately involved in selection, while administration of exogenous antigen can lead to non-specific deletion of thymocytes7-9. Currently, the best tools for studying in vivo negative selection are mice that express a transgenic TCR specific for endogenous self-antigen. However, many classical TCR transgenic models are characterized by premature expression of the transgenic TCR&alpha; chain at the DN stage, resulting in premature negative selection. Our lab has developed the HYcd4 model, in which the transgenic HY TCR&alpha; is conditionally expressed at the DP stage, allowing negative selection to occur during the DP to SP transition as occurs in wildtype mice10.
Here, we describe a flow cytometry-based protocol to examine thymic positive and negative selection in the HYcd4 mouse model. While negative selection in HYcd4 mice is highly physiological, these methods can also be applied to other TCR transgenic models. We will also present general strategies for analyzing positive selection in a polyclonal repertoire applicable to any genetically manipulated mice.

We present a flow cytometry-based method to examine T cell development in vivo using genetically manipulated mice on a wildtype or T cell receptor transgenic background.

L&#39;examen de sélection positive et négative thymique par cytométrie en flux

A healthy immune system requires that T cells respond to foreign  antigens while remaining tolerant to self-antigens. Random rearrangement of the  T cell ...

Phenotypic Characterization of Macrophages from Rat Kidney by Flow Cytometry

There is increasing evidence suggesting the important role of inflammation and, subsequently, macrophages in the development and progression of renal disease. Macrophages are heterogeneous cells that have been implicated in kidney injury. Macrophages may be classified into two different phenotypes: classically activated macrophages (M1 macrophages), that release pro-inflammatory cytokines and promote fibrosis; and alternatively activated macrophages (M2 macrophages) that are associated with immunoregulatory and tissue-remodeling functions. These macrophage phenotypes need to be discriminated and analyzed to determine their contribution to renal injury. However, there are scarce studies reporting consistent phenotypic and functional information about macrophage subtypes in inflammatory renal disease models, especially in rats. This fact may be related to the limited macrophage markers used in rats, contrary to mice. Therefore, novel strategies are necessary to quantify and characterize the renal content of these infiltrating cells in a reliable way. This manuscript details a protocol for kidney digestion and further phenotypic and quantitative analysis of macrophages from rat kidneys by flow cytometry. Briefly, kidneys were incubated with collagenase and total macrophages were identified according to the dual presence of CD45 (leukocytes common antigen) and CD68 (PAN macrophage marker) in live cells.This was followed by surface staining of CD86 (M1 marker) and CD163 (M2 marker). Rat peritoneal macrophages were used as positive control for macrophage marker detection by flow cytometry. Our protocol resulted in low cellular mortality and allowed characterization of different intracellular and surface protein markers, thus limiting the loss of cellular integrity observed in other protocols. Moreover, this procedure allows the use of macrophages for further techniques, including cell sorting and mRNA or protein expression studies, among others.

This manuscript describes a detailed protocol for phenotypic and quantitative analysis of resident macrophages from rat kidneys by flow cytometry. The resulting stained cells can be also used for other applications, including cell sorting, gene expression analysis or functional studies, thus increasing the information obtained in the experimental model.

Caractérisation phénotypique des macrophages du Rat Kidney par cytométrie de flux

There is increasing evidence suggesting the important role of inflammation and, subsequently, macrophages in the development and progression of renal ...

Assessing Retinal Microglial Phagocytic Function In Vivo Using a Flow Cytometry-based Assay

Microglia are the tissue resident macrophages of the central nervous system (CNS) and they perform a variety of functions that support CNS homeostasis, including phagocytosis of damaged synapses or cells, debris, and/or invading pathogens. Impaired phagocytic function has been implicated in the pathogenesis of diseases such as Alzheimer's and age-related macular degeneration, where amyloid-&#946; plaque and drusen accumulate, respectively. Despite its importance, microglial phagocytosis has been challenging to assess in vivo. Here, we describe a simple, yet robust, technique for precisely monitoring and quantifying the in vivo phagocytic potential of retinal microglia. Previous methods have relied on immunohistochemical staining and imaging techniques. Our method uses flow cytometry to measure microglial uptake of fluorescently labeled particles after intravitreal delivery to the eye in live rodents. This method replaces conventional practices that involve laborious tissue sectioning, immunostaining, and imaging, allowing for more precise quantification of microglia phagocytic function in just under six hours. This procedure can also be adapted to test how various compounds alter microglial phagocytosis in physiological settings. While this technique was developed in the eye, its use is not limited to vision research.

Assessing Retinal Microglial Phagocytic Function In Vivo Using a Flow Cytometry-based Assay

Microglial phagocytosis is critical for the maintenance of tissue homeostasis and inadequate phagocytic function has been implicated in pathology. However, assessing microglia function in vivo is technically challenging. We have developed a simple but robust technique for precisely monitoring and quantifying the phagocytic potential of microglia in a physiological setting.

Évaluation Retinal microglial phagocytaire Fonction<em&gt; In Vivo</em&gt; L&#39;utilisation d&#39;un test basé sur la cytométrie de flux

Microglia are the tissue resident macrophages of the central nervous system (CNS) and they perform a variety of functions that support CNS homeostasis, ...

Flow Cytometric Analysis of Particle-bound Bet v 1 Allergen in PM10

Flow cytometry is a method widely used to quantify suspended solids such as cells or bacteria in a size range from 0.5 to several tens of micrometers in diameter. In addition to a characterization of forward and sideward scatter properties, it enables the use of fluorescent labeled markers like antibodies to detect respective structures. Using indirect antibody staining, flow cytometry is employed here to quantify birch pollen allergen (precisely Bet v 1)-loaded particles of 0.5 to 10 &#181;m in diameter in inhalable particulate matter (PM10, particle size &#8804;10 &#181;m in diameter). PM10 particles may act as carriers of adsorbed allergens possibly transporting them to the lower respiratory tract, where they could trigger allergic reactions.
So far the allergen content of PM10 has been studied by means of enzyme linked immunosorbent assays (ELISAs) and scanning electron microscopy. ELISA measures the dissolved and not the particle-bound allergen. Compared to scanning electron microscopy, which can visualize allergen-loaded particles, flow cytometry may additionally quantify them. As allergen content of ambient air can deviate from birch pollen count, allergic symptoms might perhaps correlate better with allergen exposure than with pollen count. In conjunction with clinical data, the presented method offers the opportunity to test in future experiments whether allergic reactions to birch pollen antigens are associated with the Bet v 1 allergen content of PM10 particles &#62;0.5 &#181;m.

Here, we present a protocol to quantify allergen-loaded particles by flow cytometry. Ambient particulate matter particles may act as carriers of adsorbed allergens. We show here that flow cytometry, a method widely used to characterize suspended solids &#62;0.5 &#181;m in diameter, can be used to measure these allergen-loaded particles.

Cytométrie en flux Analyse de la particule liée Bet v 1 Allergène en PM10

Flow cytometry is a method widely used to quantify suspended solids such as cells or bacteria in a size range from 0.5 to several tens of micrometers in ...

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 ...

Characterization of Human Monocyte Subsets by Whole Blood Flow Cytometry Analysis

Monocytes are key contributors in various inflammatory disorders and alterations to these cells, including their subset proportions and functions, can have pathological significance. An ideal method for examining alterations to monocytes is whole blood flow cytometry as the minimal handling of samples by this method limits artifactual cell activation. However, many different approaches are taken to gate the monocyte subsets leading to inconsistent identification of the subsets between studies. Here we demonstrate a method using whole blood flow cytometry to identify and characterize human monocyte subsets (classical, intermediate, and non-classical). We outline how to prepare the blood samples for flow cytometry, gate the subsets (ensure contaminating cells have been removed), and determine monocyte subset expression of surface markers &#8212; in this example M1 and M2 markers. This protocol can be extended to other studies that require a standard gating method for assessing monocyte subset proportions and monocyte subset expression of other functional markers.

Here we present a protocol for characterizing monocyte subsets by whole blood flow cytometry. This includes outlining how to gate the subsets and assess their expression of surface markers and giving an example of the assessment of the expression of M1 (inflammatory) and M2 markers (anti-inflammatory).

Caractérisation des sous-ensembles de Monocyte humain de sang Flow Cytometry analyse

Monocytes are key contributors in various inflammatory disorders and alterations to these cells, including their subset proportions and functions, can ...

Discrimination of Seven Immune Cell Subsets by Two-fluorochrome Flow Cytometry

Immune cell characterization heavily relies on multicolor flow cytometry to identify subpopulations based on differential expression of surface markers. Setup of a classic multicolor panel requires high-end instruments, custom labeled antibodies, and careful study design to minimize spectral overlap. We developed a multiparametric analysis to identify major human immune populations (CD4+ and CD8+ T cells, &#947;&#948; T cells, B cells, NK cells and monocytes) in peripheral blood by combining seven lineage markers using only two fluorochromes. Our strategy is based on the observation that lineage markers are constantly expressed in a unique combination by each cell population. Combining this information with a careful titration of the antibodies allows investigators to record five additional markers, expanding the optical limit of most flow cytometers. Head-to-head comparison demonstrated that the vast majority of immune cell populations in peripheral blood can be characterized with comparable accuracy between our method and the classic &#34;one fluorochrome-one marker approach&#34;, although the latter is still more precise for identifying populations such as NKT cells and &#947;&#948; T cells. Combining seven markers using two fluorochromes allows for the analysis of complex immune cell populations and clinical samples on affordable 6-10 fluorochrome flow cytometers, and even on 2-3 fluorochrome field instruments in areas with limited resources. High-end instruments can also benefit from this approach by using extra fluorochromes to accomplish deeper flow cytometry analysis. This approach is also very well suited for screening several cell populations in the case of clinical samples with limited number of cells.

Here, we present a flow cytometric protocol to identify CD4+ and CD8+ T cells, &#947;&#948; T cells, B cells, NK cells and monocytes in human peripheral blood by using only two fluorochromes instead of seven. With this approach, five additional markers can be recorded on most flow cytometers.

Discrimination des sept sous-ensembles de cellules immunitaires par deux-fluorochrome cytométrie en flux

Immune cell characterization heavily relies on multicolor flow cytometry to identify subpopulations based on differential expression of surface markers. ...