この作品は、CSおよびSecretaríaナシオナルデCiencia yをTecnología（SENACYT）からLCに博士課程奨学金、パナマへの助成PRB-009によって賄われていた。

プロトコルのすべてのステップは、遠心分離を除いて、サンプルを無菌に保つためにフード内に実施されるべきである。 1。 Pの後期段階の分離熱帯熱マラリア原虫感染赤血球寄生虫で常磁性を付与hemozoinが、属に共通の代謝物であるので、マラリア原虫感染赤血球のすべての後期段階では、この方法論で区切ることができます。文化の高い寄生虫（3-10％）はこのプロトコルを使用してより良い収率を得るために推奨される、典型的な文化は2-4％のヘマトクリット（赤血球容積率）、1〜8％の寄生虫血症（感染の割合が含まれますが、赤血球）。トレガとヤンセン1で説明したように寄生虫は培養することができる。 <ol><li>シンプル、マルチパートの設定はすべてのシゾント分離手順のために組み立てる必要があります。このために、LSの列、磁気MidiMACSセパレータとミルテニーバイオテク（ 図1からMACS MultiStand </strong&gt;）を使用されています。まず、金属スタンドに磁気分離器をアタッチし、セパレータに磁気カラムを配置します。 </li><li>別のチューブに（全体で50ミリリットルconicalsを使用）、RPMI1640の23.2ミリリットルと作業ソリューションを作成する7.5％の炭酸水素ナトリウム750μlを混合します。廃棄するため手で追加のチューブを持っていると寄生虫文化のフロースルー収集。 </li><li>それを平衡化するために列に作業溶液3mlを追加し、フロースルーチューブには廃棄してください。 </li><li> Pの8ミリリットルを追加列に熱帯熱マラリア原虫は、文化、できるだけ早く作業ソリューションの最後の部分として培養による列から押し出されていることを確認して、受信したチューブは、結合していない文化のリカバリを開始する収集で置き換えられます。これは、任意のさらなる文化を希釈を避けるために必要です。 </li><li>コラムを通じて文化の流れが止まった後、列の残りの赤血球を押し出すために、作業溶液1mlを加える。 </li><li>ステップを洗濯：列に作業ソリューションの別の3ミリリットルを追加し、他のチューブにフロースルーとして保存されている文化を希釈避けるために、 &quot;廃棄&quot;チューブに流れる液体を収集します。 </li><li>溶出：3ミリリットルがカラムを通過した後は、スタンドから後者を切り離し、15 mlチューブの上に置きます。 </li><li>繰り返しになりますが、列に作業溶液3mlを加える。このステップでは、列のビーズに閉じ込められた後期原虫感染赤血球を溶出する。 </li></ol> 注：この時点で、必要に寄生虫の量に応じて、元の文化の中で寄生虫の限界に明らかに被写体コレクションの別のラウンド/ sを開始します。流れが定常状態を維持している列であれば再利用することができます。 <ol start="9"><li>収集された寄生虫の濃度：室温で150×gで5分間溶出液を含む15 mlチューブを遠心寄生された赤血球から濃いペレットを形成する。 </li><li> （以下の手順2を参照してください）​​非常に小さいサンプルを取り、顕微鏡を通して濃度と総収量を決定するのに十分な液体残して上清を取り除きます。 </li><li>後期原虫の分離と回収が十分に達成されている場合は、この時点では、新鮮な培地を再び回収した培養をインキュベートする。 </li><li>その後の実験に必要なボリュームと溶液中で収集された寄生虫を希釈します。 </li></ol> 2。純度や歩留まり解析<ol><li>血球計数器を用いて、光学顕微鏡下でカウントした寄生虫の濃度を確認します。カウントするには、血球計数器のカバースリップの下で収集寄生虫やメディアミックスの10μlを添加する。血球計数器の4つの象限の寄生虫の数を数えて、4で合計数を割る。感染した電子の濃度を得るために、10 4によって、その数を掛けるmlあたりrythrocytes。 </li></ol> ノート：a）混合物の濃度が、多かれ少なかれ、培地を加えて、ペレットを再懸濁した瞬間にユーザによって決定される。作業濃度がμlあたり5.5×10 4 schizontes（これは一般的に収集された寄生虫に100から300μlを添加することによって達成される）が示唆された。この濃度の20μlをメディアや赤血球100μlのミックスの最終容量に追加された場合は、代表的な4％ヘマトクリット文化で約1％の寄生虫血が得られるであろう。 B）血球計算板の下にカウントは、赤血球がチャンバ内の試料が乾燥として溶解開始以来、迅速でなければならない。過半数であるべき感染赤血球は、非感染のものからそれらを区別するダークスポットの内側を、表示されます。 <ol start="2"><li>薄層を実行ギムザ、それらを乾燥させ、10％メタノールで非常に急速にスライドを固定することによって、コレクションの純度を評価するために染色し、tを浸漬ギムザの20％溶液で裾を蒸留水で希釈した染色。彼らは空気で乾燥した後、顕微鏡下で検査できるようになるまでの10分間、スライドを染色する。よく70％以上の寄生虫は達成可能である必要があります。 </li></ol>

<ol>
	<li>Jensen, J. B., Trager, W. <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+in+culture:+use+of+outdated+erythrocytes+and+description+of+the+candle+jar+method.">Plasmodium falciparum in culture: use of outdated erythrocytes and description of the candle jar method.</a> J. Parasitology. 63 (5), 883-886 (1977).</li><li>Guzman, I. Y., Francis, S. E., Oksman, A., Smith, C. E., Duffin, K. L., Goldberg, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Order+and+specificity+of+the+Plasmodium+falciparum+hemoglobin+degradation+pathway.">Order and specificity of the Plasmodium falciparum hemoglobin degradation pathway.</a> J. Clin. Invest. 93, 1602-1608 (1994).</li><li>Rosenthal, P. J., Meshnick, S. 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W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathobiology+of+heme+interaction+with+the+erythrocyte+membrane.">Pathobiology of heme interaction with the erythrocyte membrane.</a> Semin. Hematol. 26 (2), 136-149 (1989).</li><li>Egan, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Haemozoin+formation.">Haemozoin formation.</a> Mol. Biochem. Parasitol. 157 (2), 127-136 (2008).</li><li>Hempelmann, E., Marques, H. M. <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+pigment+from+Plasmodium+falciparum.">Analysis of malaria pigment from Plasmodium falciparum.</a> J. Pharmacol. Toxicol. Methods. 32 (1), 25-30 (1994).</li><li>Fitch, C. D., Kanjananggulpan, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+state+of+ferriprotoporphyrin+IX+in+malaria+pigment.">The state of ferriprotoporphyrin IX in malaria pigment.</a> J. Biol. Chem. 262 (32), 15552-15555 (1987).</li><li>Moore, L. R., Fujioka, H., Williams, P. S., Chalmers, J. J., Grimberg, B., Zimmerman, P. A., Zborowski, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hemoglobin+degradation+in+malaria-infected+erythrocytes+determined+from+live+cell+magnetophoresis.">Hemoglobin degradation in malaria-infected erythrocytes determined from live cell magnetophoresis.</a> FASEB J. 20 (6), 747-749 (2006).</li><li>Spadafora, C., Gerena, L., Kopydlowski, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+the+in+vitro+invasive+capabilities+of+Plasmodium+falciparum+schizonts+isolated+by+Percoll+gradient+or+using+magnetic+based+separation.">Comparison of the in vitro invasive capabilities of Plasmodium falciparum schizonts isolated by Percoll gradient or using magnetic based separation.</a> Malaria J. 10, 96 (2011).</li><li>Jackson, K. E., Spielmann, T., Hanssen, E., Adisa, A., Separovic, F., Dixon, M. W., Trenholme, K. R., Hawthorne, P. L., Gardiner, D. L., Gilberger, T., Tilley, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+permeabilization+of+the+host+cell+membrane+of+Plasmodium+falciparum-infected+red+blood+cells+with+streptolysin+O+and+equinatoxin+II.">Selective permeabilization of the host cell membrane of Plasmodium falciparum-infected red blood cells with streptolysin O and equinatoxin II.</a> Biochem. J. 403, 167-175 (2007).</li><li>Goodyer, I. D., Johnson, J., Eisenthal, R., Hayes, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+of+mature-stage+Plasmodium+falciparum+by+gelatine+flotation.">Purification of mature-stage Plasmodium falciparum by gelatine flotation.</a> Ann. Trop. Med. Parasitol. 88 (2), 209-211 (1994).</li><li>Pasvol, G., Wilson, R. J., Smalley, M. E., Brown, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Separation+of+viable+schizont-infected+red+cells+of+Plasmodium+falciparum+from+human+blood.">Separation of viable schizont-infected red cells of Plasmodium falciparum from human blood.</a> Ann. Trop. Med. Parasitol. 72, 87-88 (1978).</li><li>Pertoft, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fractionation+of+cells+and+subcellular+particles+with+Percoll.">Fractionation of cells and subcellular particles with Percoll.</a> J. Biochem. Biophys. Methods. 44 (1-2), 1-30 (2000).</li><li>Paul, F., Roath, S., Melville, D., Warhurst, D. C., Osisanya, J. O. 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我々は、開示することは何もない。

マラリア原虫P.の in vitro 培養における熱帯熱マラリア原虫は、より文化の最高増殖時点で感染していない赤血球の半分以下で、限られた寄生虫血症を呈する。ほとんどの研究実験のためには、感染赤血球でのみ動作することが望ましい。この目的を達成するために、分離技術は、感染によると文化を分割することが必要である。便利なメソッドは非感染赤血球11と二つの...

<table border="1"><tbody><tr><td> 試薬の名称 </td><td> 会社 </td><td> カタログ番号 </td><td> コメント（オプション） </td></tr><tr><td>修正したRPMI 1640ヘペス</td><td>シグマアルドリッチ</td><td> R4130 </td><td> 10％ヒト血清、2％グルコース、0.2％炭酸水素ナトリウムを補充</td></tr><tr><td> MidiMACSセパレータ</td><td> MACSミルテニーバイオテク</td><td> 130-042-302 </td><td></td></tr><tr><td> MACS MultiStand </td><td> MACSミルテニーバイオテク</td><td> 130-042-303 </td><td></td></tr><tr><td> LSの列</td><td> MACSミルテニーバイオテク</td><td> 130-042-401 </td><td></td></tr><tr><td>血球計</td><td> Grafco </td><td> Grafcoノイバウアー商工会議所</td><td>多くの他のサプライヤーを通じて見つけることができます</td></tr></tbody></table>

separation of plasmodium falciparum late stage-infected erythrocytes by magnetic means

他の原虫種とは異なり、P.熱帯熱マラリア原虫は、その研究1を容易に実験室で培養することができる。達成寄生虫は≈40％の限界に達することができますが、治験責任医師は、通常約10％の割合を維持します。多くの場合、それが文化を豊かにし、与えられた実験を続行し、感染していないものから寄生虫含有赤血球細胞（赤血球）を単離することが必要である。 ときはP.熱帯熱マラリア原虫が赤血球に感染する寄生虫が低下し、ヘモグロビン2,3から供給されます。しかし、寄生虫は非常に有毒な鉄を含有するヘム部分4,5に対処する必要があります。寄生虫はhaemozoin 6,7と呼ばれる不活性液晶ポリマーにヘムを変換することによって、その毒性は見逃されている。この鉄含有分子は、その食胞に格納されており、その中に金属がヘム8のものと異なる酸化状態を有している。ヘム鉄の鉄状態ozoinはそれに感染していない赤血球中に存在しない常磁性を付与する。侵略の寄生虫が成熟に達すると、haemozoinの内容もPの最新のステージでさらに常磁性を授けている、9を増加赤血球内部の熱帯熱マラリア 。 この常磁性、Pの最新の段階に基づいてfalciparum感染、赤血球は、磁気ビーズを含むカラムを通して文化を通過させることによって分離することができる。それらを含む列がマグネットホルダ上に配置された場合、これらのビーズは、磁気になる。フロースルーは、ほとんどの部分、非感染赤血球および寄生虫の含有するもの初期段階のため、含まれていながら、常磁性に起因する感染した赤血球は、その後、列の中に閉じ込められます。 ここで、我々は良い寄生虫の生存率10を維持した磁気カラムを持つ後期寄生虫の人口を豊かにするための方法論を記述している。この手順を実行した後、付着していない文化が残っている寄生虫が成長し続けることができるようにインキュベーターに戻すことができます。

図2では、磁気カラムを通過する文化が前（A）と手順（B）後、表示されます。矢印は、 図2Aの感染赤血球を指すと、 図2に示すように、1〜2感染赤血球は通常100X倍率分野で見られる。典型的な手順では、5％の寄生虫血症（ 図2A）で培養を皮切りに、この手順のパフォーマンスは、通常97パーセント-100％（ 図2B?...

Watch this Scientific Journal Video about Separation of Plasmodium falciparum Late Stage-infected Erythrocytes by Magnetic Means at JoVE.com

Separation of Plasmodium falciparum Late Stage-infected Erythrocytes by Magnetic Means

hemozoinの常磁性特性は後期を分離するために使用されている<em&gt;熱帯熱マラリア原虫（Plasmodium falciparum）</em&gt;感染した赤血球は、文化の中で成長しています。方法は、シンプルで早いのが特長です、寄生虫のその後の侵襲的な機能に影響を与えません。

の分離<em&gt;熱帯熱マラリア原虫（Plasmodium falciparum）</em磁気手段によって&gt;後期感染赤血球

Unlike other Plasmodium species, P. falciparum can be cultured in the lab, which facilitates its study 1. While the parasitemia achieved can reach the ...

separation-plasmodium-falciparum-late-stage-infected-erythrocytes

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Immunology and Infection

Separation of Plasmodium falciparum Late Stage-infected Erythrocytes by Magnetic Means

13.8K ビュー.  Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP). hemozoinの常磁性特性は後期を分離するために使用されている熱帯熱マラリア原虫（Plasmodium falciparum）感染した赤血球は、文化の中で成長しています。方法は、シンプルで早いのが特長です、寄生虫のその後の侵襲的な機能に影響を与えません。

ビデオ: Separation of Plasmodium falciparum Late Stage-infected Erythrocytes by Magnetic Means

Ex vivo Expansion of Tumor-reactive T Cells by Means of Bryostatin 1/Ionomycin and the Common Gamma Chain Cytokines Formulation

It was reported that breast cancer patients have pre-existing immune responses against their tumors1,2. However, such immune responses fail to provide complete protection against the development or recurrence of breast cancer. To overcome this problem by increasing the frequency of tumor-reactive T cells, adoptive immunotherapy has been employed. A variety of protocols have been used for the expansion of tumor-specific T cells. These protocols, however, are restricted to the use of tumor antigens ex vivo for the activation of antigen-specific T cells. Very recently, common gamma chain cytokines such as IL-2, IL-7, IL-15, and IL-21 have been used alone or in combination for the enhancement of anti-tumor immune responses3. However, it is not clear what formulation would work best for the expansion of tumor-reactive T cells. Here we present a protocol for the selective activation and expansion of tumor-reactive T cells from the FVBN202 transgenic mouse model of HER-2/neu positive breast carcinoma for use in adoptive T cell therapy of breast cancer. The protocol includes activation of T cells with bryostatin-1/ionomycin (B/I) and IL-2 in the absence of tumor antigens for 16 hours. B/I activation mimics intracellular signals that result in T cell activation by increasing protein kinase C activity and intracellular calcium, respectively4. This protocol specifically activates tumor-specific T cells while killing irrelevant T cells. The B/I-activated T cells are cultured with IL-7 and IL-15 for 24 hours and then pulsed with IL-2. After 24 hours, T cells are washed, split, and cultured with IL-7 + IL-15 for additional 4 days. Tumor-specificity and anti-tumor efficacy of the ex vivo expanded T cells is determined.

Ex vivo Expansion of Tumor-reactive T Cells by Means of Bryostatin 1/Ionomycin and the Common Gamma Chain Cytokines Formulation

An efficient protocol for the ex vivo expansion of tumor-reactive T cells from tumor-draining lymph nodes or other secondary lymphoid tissues of tumor-bearing hosts is described. This protocol selectively expands tumor-specific T cells for use in adoptive immunotherapy of breast cancer.

ブリオスタチンの1/Ionomycinによる腫瘍反応性T細胞のex vivoでの拡張と共通γ鎖のサイトカインの策定

It was reported that breast cancer patients have pre-existing immune responses against their tumors1,2. However, such immune responses fail to provide ...

免疫・感染学

Selection of Plasmodium falciparum Parasites for Cytoadhesion to Human Brain Endothelial Cells

Most human malaria deaths are caused by blood-stage Plasmodium falciparum parasites. Cerebral malaria, the most life-threatening complication of the disease, is characterised by an accumulation of Plasmodium falciparum infected red blood cells (iRBC) at pigmented trophozoite stage in the microvasculature of the brain2-4. This microvessel obstruction (sequestration) leads to acidosis, hypoxia and harmful inflammatory cytokines (reviewed in 5). Sequestration is also found in most microvascular tissues of the human body2, 3. The mechanism by which iRBC attach to the blood vessel walls is still poorly understood.
The immortalized Human Brain microvascular Endothelial Cell line (HBEC-5i) has been used as an in vitro model of the blood-brain barrier6. However, Plasmodium falciparum iRBC attach only poorly to HBEC-5i in vitro, unlike the dense sequestration that occurs in cerebral malaria cases. We therefore developed a panning assay to select (enrich) various P. falciparum strains for adhesion to HBEC-5i in order to obtain populations of high-binding parasites, more representative of what occurs in vivo.
A sample of a parasite culture (mixture of iRBC and uninfected RBC) at the pigmented trophozoite stage is washed and incubated on a layer of HBEC-5i grown on a Petri dish. After incubation, the dish is gently washed free from uRBC and unbound iRBC. Fresh uRBC are added to the few iRBC attached to HBEC-5i and incubated overnight. As schizont stage parasites burst, merozoites reinvade RBC and these ring stage parasites are harvested the following day. Parasites are cultured until enough material is obtained (typically 2 to 4 weeks) and a new round of selection can be performed. Depending on the P. falciparum strain, 4 to 7 rounds of selection are needed in order to get a population where most parasites bind to HBEC-5i. The binding phenotype is progressively lost after a few weeks, indicating a switch in variant surface antigen gene expression, thus regular selection on HBEC-5i is required to maintain the phenotype.
In summary, we developed a selection assay rendering P. falciparum parasites a more "cerebral malaria adhesive" phenotype. We were able to select 3 out of 4 P. falciparum strains on HBEC-5i. This assay has also successfully been used to select parasites for binding to human dermal and pulmonary endothelial cells. Importantly, this method can be used to select tissue-specific parasite populations in order to identify candidate parasite ligands for binding to brain endothelium. Moreover, this assay can be used to screen for putative anti-sequestration drugs7.

Selection of Plasmodium falciparum Parasites for Cytoadhesion to Human Brain Endothelial Cells

An in vitro model for cerebral malaria sequestration is described1. Plasmodium falciparum infected red blood cells are selected for binding to immortalized human brain microvascular endothelial cells. The selected parasites show a distinct phenotype. The selection process can be applied using various P. falciparum strains and endothelial cell lines.

の選択熱帯熱マラリア原虫</em人間の脳内皮細胞へのCytoadhesion用>寄生虫

Most human malaria deaths are caused by blood-stage Plasmodium falciparum parasites. Cerebral malaria, the most life-threatening complication of the ...

An In vitro Co-infection Model to Study Plasmodium falciparum-HIV-1 Interactions in Human Primary Monocyte-derived Immune Cells

Plasmodium falciparum, the causative agent of the deadliest form of malaria, and human immunodeficiency virus type-1 (HIV-1) are among the most important health problems worldwide, being responsible for a total of 4 million deaths annually1. Due to their extensive overlap in developing regions, especially Sub-Saharan Africa, co-infections with malaria and HIV-1 are common, but the interplay between the two diseases is poorly understood. Epidemiological reports have suggested that malarial infection transiently enhances HIV-1 replication and increases HIV-1 viral load in co-infected individuals2,3. Because this viremia stays high for several weeks after treatment with antimalarials, this phenomenon could have an impact on disease progression and transmission.
The cellular immunological mechanisms behind these observations have been studied only scarcely. The few in vitro studies investigating the impact of malaria on HIV-1 have demonstrated that exposure to soluble malarial antigens can increase HIV-1 infection and reactivation in immune cells. However, these studies used whole cell extracts of P. falciparum schizont stage parasites and peripheral blood mononuclear cells (PBMC), making it hard to decipher which malarial component(s) was responsible for the observed effects and what the target host cells were4,5. Recent work has demonstrated that exposure of immature monocyte-derived dendritic cells to the malarial pigment hemozoin increased their ability to transfer HIV-1 to CD4+ T cells6,7, but that it decreased HIV-1 infection of macrophages8. To shed light on this complex process, a systematic analysis of the interactions between the malaria parasite and HIV-1 in different relevant human primary cell populations is critically needed.
Several techniques for investigating the impact of HIV-1 on the phagocytosis of micro-organisms and the effect of such pathogens on HIV-1 replication have been described. We here present a method to investigate the effects of P. falciparum-infected erythrocytes on the replication of HIV-1 in human primary monocyte-derived macrophages. The impact of parasite exposure on HIV-1 transcriptional/translational events is monitored by using single cycle pseudotyped viruses in which a luciferase reporter gene has replaced the Env gene while the effect on the quantity of virus released by the infected macrophages is determined by measuring the HIV-1 capsid protein p24 by ELISA in cell supernatants.

An In vitro Co-infection Model to Study Plasmodium falciparum-HIV-1 Interactions in Human Primary Monocyte-derived Immune Cells

We have developed an in vitro malaria-HIV-1 co-infection model to study the impact of Plasmodium falciparum on the HIV-1 replicative cycle in human primary monocyte-derived macrophages. This versatile system can easily be adapted to other primary cell types susceptible to HIV-1 infection.

不定冠詞<em&gt;のin vitro</em研究する&gt;共同感染モデル<em&gt;熱帯熱マラリア原虫（Plasmodium falciparum）</emヒトの第一次単球由来の免疫細胞に&gt;-HIV-1の相互作用

Plasmodium falciparum, the causative agent  of the deadliest form of malaria, and human immunodeficiency virus type-1 (HIV-1) are among the most important ...

A Simple Protocol for Platelet-mediated Clumping of Plasmodium falciparum-infected Erythrocytes in a Resource Poor Setting

P. falciparum causes the majority of severe malarial infections. The pathophysiological mechanisms underlying cerebral malaria (CM) are not fully understood and several hypotheses have been put forward, including mechanical obstruction of microvessels by P. falciparum-parasitized red blood cells (pRBC). Indeed, during the intra-erythrocytic stage of its life cycle, P. falciparum has the unique ability to modify the surface of the infected erythrocyte by exporting surface antigens with varying adhesive properties onto the RBC membrane. This allows the sequestration of pRBC in multiple tissues and organs by adhesion to endothelial cells lining the microvasculature of post-capillary venules 1. By doing so, the mature forms of the parasite avoid splenic clearance of the deformed infected erythrocytes 2 and restrict their environment to a more favorable low oxygen pressure 3. As a consequence of this sequestration, it is only immature asexual parasites and gametocytes that can be detected in peripheral blood.
Cytoadherence and sequestration of mature pRBC to the numerous host receptors expressed on microvascular beds occurs in severe and uncomplicated disease. However, several lines of evidence suggest that only specific adhesive phenotypes are likely to be associated with severe pathological outcomes of malaria. One example of such specific host-parasite interactions has been demonstrated in vitro, where the ability of intercellular adhesion molecule-1 to support binding of pRBC with particular adhesive properties has been linked to development of cerebral malaria 4,5. The placenta has also been recognized as a site of preferential pRBC accumulation in malaria-infected pregnant women, with chondrotin sulphate A expressed on syncytiotrophoblasts that line the placental intervillous space as the main receptor 6. Rosetting of pRBC to uninfected erythrocytes via the complement receptor 1 (CD35)7,8 has also been associated with severe disease 9.
One of the most recently described P. falciparum cytoadherence phenotypes is the ability of the pRBC to form platelet-mediated clumps in vitro. The formation of such pRBC clumps requires CD36, a glycoprotein expressed on the surface of platelets. Another human receptor, gC1qR/HABP1/p32, expressed on diverse cell types including endothelial cells and platelets, has also been shown to facilitate pRBC adhesion on platelets to form clumps 10. Whether clumping occurs in vivo remains unclear, but it may account for the significant accumulation of platelets described in brain microvasculature of Malawian children who died from CM 11. In addition, the ability of clinical isolate cultures to clump in vitro was directly linked to the severity of disease in Malawian 12 and Mozambican patients 13, (although not in Malian 14).
With several aspects of the pRBC clumping phenotype poorly characterized, current studies on this subject have not followed a standardized procedure. This is an important issue because of the known high variability inherent in the assay 15. Here, we present a method for in vitro platelet-mediated clumping of P. falciparum with hopes that it will provide a platform for a consistent method for other groups and raise awareness of the limitations in investigating this phenotype in future studies. Being based in Malawi, we provide a protocol specifically designed for a limited resource setting, with the advantage that freshly collected clinical isolates can be examined for phenotype without need for cryopreservation.

A Simple Protocol for Platelet-mediated Clumping of Plasmodium falciparum-infected Erythrocytes in a Resource Poor Setting

This method investigates the platelet-mediated clumping phenotype of Plasmodium falciparum-infected erythrocytes (pRBC) in clinical isolates. This is performed by isolating and co-incubating platelet-rich plasma and a suspension of pRBC.

の血小板媒介クランピングのためのシンプルなプロトコル<em&gt;熱帯熱マラリア原虫</emリソース悪い設定で、&gt;感染した赤血球

P. falciparum causes the majority of severe malarial infections. The pathophysiological mechanisms underlying cerebral malaria (CM) are not fully ...

Isolation and Analysis of Brain-sequestered Leukocytes from Plasmodium berghei ANKA-infected Mice

We describe a method for isolation and characterization of adherent inflammatory cells from brain blood vessels of P. berghei ANKA-infected mice. Infection of susceptible mouse-strains with this parasite strain results in the induction of experimental cerebral malaria, a neurologic syndrome that recapitulates certain important aspects of Plasmodium falciparum-mediated severe malaria in humans 1,2 . Mature forms of blood-stage malaria express parasitic proteins on the surface of the infected erythrocyte, which allows them to bind to vascular endothelial cells. This process induces obstructions in blood flow, resulting in hypoxia and haemorrhages 3 and also stimulates the recruitment of inflammatory leukocytes to the site of parasite sequestration.
Unlike other infections, i.e neutrotopic viruses4-6, both malaria-parasitized red blood cells (pRBC) as well as associated inflammatory leukocytes remain sequestered within blood vessels rather than infiltrating the brain parenchyma. Thus to avoid contamination of sequestered leukocytes with non-inflammatory circulating cells, extensive intracardial perfusion of infected-mice prior to organ extraction and tissue processing is required in this procedure to remove the blood compartment. After perfusion, brains are harvested and dissected in small pieces. The tissue structure is further disrupted by enzymatic treatment with Collagenase D and DNAse I. The resulting brain homogenate is then centrifuged on a Percoll gradient that allows separation of brain-sequestered leukocytes (BSL) from myelin and other tissue debris. Isolated cells are then washed, counted using a hemocytometer and stained with fluorescent antibodies for subsequent analysis by flow cytometry.
This procedure allows comprehensive phenotypic characterization of inflammatory leukocytes migrating to the brain in response to various stimuli, including stroke as well as viral or parasitic infections. The method also provides a useful tool for assessment of novel anti-inflammatory treatments in pre-clinical animal models.

Isolation and Analysis of Brain-sequestered Leukocytes from Plasmodium berghei ANKA-infected Mice

A method for isolation of adherent inflammatory leukocytes from brain blood vessels of Plasmodium berghei ANKA-infected mice is described. The method allows quantification as well as phenotypic characterization of isolated leukocytes after staining with fluorescent antibodies and subsequent analysis by flow cytometry.

脳から隔離された白血球の単離と解析<em&gt;マラリアベルゲイ</em&gt; ANKA感染マウス

We describe a method for isolation and  characterization of adherent inflammatory cells from brain blood vessels of P. berghei ANKA-infected mice. ...

Automated Separation of C. elegans Variably Colonized by a Bacterial Pathogen

The wormsorter is an instrument analogous to a FACS machine that is used in studies of Caenorhabditis elegans, typically to sort worms based on expression of a fluorescent reporter. Here, we highlight an alternative usage of this instrument, for sorting worms according to their degree of colonization by a GFP-expressing pathogen. This new usage allowed us to address the relationship between colonization of the worm intestine and induction of immune responses. While C. elegans immune responses to different pathogens have been documented, it is still unknown what initiates them. The two main possibilities (which are not mutually exclusive) are recognition of pathogen-associated molecular patterns, and detection of damage caused by infection. To differentiate between the two possibilities, exposure to the pathogen must be dissociated from the damage it causes. The wormsorter enabled separation of worms that were extensively-colonized by the Gram-negative pathogen Pseudomonas aeruginosa, with the damage likely caused by pathogen load, from worms that were similarly exposed, but not, or marginally, colonized. These distinct populations were used to assess the relationship between pathogen load and the induction of transcriptional immune responses. The results suggest that the two are dissociated, supporting the possibility of pathogen recognition.

Automated Separation of C. elegans Variably Colonized by a Bacterial Pathogen

The wormsorter facilitates genetic screens in Caenorhabditis elegans by sorting worms according to expression of fluorescent reporters. Here, we describe a new usage:&#160;sorting according to colonization by a GFP-expressing pathogen, and we employ it to examine the poorly understood role of pathogen recognition in initiating immune responses.

の自動分離<em&gt; C.虫</em&gt;可変細菌性病原体の植民地

The wormsorter is an instrument analogous to a FACS machine that is used in studies of Caenorhabditis elegans, typically to sort worms based on expression ...

High Yield Purification of Plasmodium falciparum Merozoites For Use in Opsonizing Antibody Assays

Plasmodium falciparum merozoite antigens are under development as potential malaria vaccines. One aspect of immunity against malaria is the removal of free merozoites from the blood by phagocytic cells. However assessing the functional efficacy of merozoite specific opsonizing antibodies is challenging due to the short half-life of merozoites and the variability of primary phagocytic cells. Described in detail herein is a method for generating viable merozoites using the E64 protease inhibitor, and an assay of merozoite opsonin-dependent phagocytosis using the pro-monocytic cell line THP-1. E64 prevents schizont rupture while allowing the development of merozoites which are released by filtration of treated schizonts. &#160;Ethidium bromide labelled merozoites are opsonized with human plasma samples and added to THP-1 cells. Phagocytosis is assessed by a standardized high throughput protocol. Viable merozoites are a valuable resource for assessing numerous aspects of P. falciparum biology, including assessment of immune function. Antibody levels measured by this assay are associated with clinical immunity to malaria in naturally exposed individuals. The assay may also be of use for assessing vaccine induced antibodies. &#160;

High Yield Purification of Plasmodium falciparum Merozoites For Use in Opsonizing Antibody Assays

Measuring antibody function is key to understanding immunity to Plasmodium falciparum malaria. This method describes the purification of viable merozoites, and measurement of opsonization-dependent phagocytosis by flow cytometry.

高収率の精製<em&gt;熱帯熱マラリア原虫</emオプソニン抗体アッセイにおける使用のための&gt;メロゾイト

Plasmodium falciparum merozoite antigens are under development as potential malaria vaccines. One aspect of immunity against malaria is the removal of ...

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.

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

The malaria parasite invades and replicates within red blood cells. The accurate assessment of merozoite invasion and parasitemia is therefore crucial in assessing the course of malaria infection. Here we describe a flow cytometry based protocol for the measurement of these parameters in a mouse model of malaria.

フローサイトメトリーによるげっ歯類マラリア原虫のin vivo評価とメロゾイト侵略で

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

Methods to Investigate the Regulatory Role of Small RNAs and Ribosomal Occupancy of Plasmodium falciparum

The genetic variation responsible for the sickle cell allele (HbS) enables erythrocytes to resist infection by the malaria parasite, P. falciparum. The molecular basis of this resistance, which is known to be multifactorial, remains incompletely understood. Recent studies found that the differential expression of erythrocyte microRNAs, once translocated into malaria parasites, affect both gene regulation and parasite growth. These miRNAs were later shown to inhibit mRNA translation by forming a chimeric RNA transcript via 5&#39; RNA fusion with discreet subsets of parasite mRNAs. Here, the techniques that were used to study the functional role and putative mechanism underlying erythrocyte microRNAs on the gene regulation and translational potential of P. falciparum, including the transfection of modified synthetic microRNAs into host erythrocytes, will be detailed.&#160; Finally, a polysome gradient method is used to determine the extent of translation of these transcripts. Together, these techniques allowed us to demonstrate that the dysregulated levels of erythrocyte microRNAs contribute to cell-intrinsic malaria resistance of sickle erythrocytes.

Methods to Investigate the Regulatory Role of Small RNAs and Ribosomal Occupancy of Plasmodium falciparum

Human microRNAs translocate from host erythrocytes to Plasmodium falciparum parasites. Here, the techniques used to transfect synthetic microRNAs into host erythrocytes and isolate all RNAs from P. falciparum are described. In addition, this paper will detail a method of polysome isolation in P. falciparum to determine the ribosomal occupancy and translational potential of parasite transcripts.

小さなRNAおよびリボソームの占有の調節の役割を調査する方法<em&gt;熱帯熱マラリア原虫</em

The genetic variation responsible for the sickle cell allele (HbS) enables erythrocytes to resist infection by the malaria parasite, P. falciparum. The ...

Bioluminescence Imaging to Detect Late Stage Infection of African Trypanosomiasis

Human African trypanosomiasis (HAT) is a multi-stage disease that manifests in two stages; an early blood stage and a late stage when the parasite invades the central nervous system (CNS). In vivo study of the late stage has been limited as traditional methodologies require the removal of the brain to determine the presence of the parasites.
Bioluminescence imaging is a non-invasive, highly sensitive form of optical imaging that enables the visualization of a luciferase-transfected pathogen in real-time. By using a transfected trypanosome strain that has the ability to produce late stage disease in mice we are able to study the kinetics of a CNS infection in a single animal throughout the course of infection, as well as observe the movement and dissemination of a systemic infection.
Here we describe a robust protocol to study CNS infections using a bioluminescence model of African trypanosomiasis, providing real time non-invasive observations which can be further analyzed with optional downstream approaches.

This manuscript describes the use of a bioluminescent strain of African trypanosomes to enable the tracking of late stage infection and demonstrates how in vivo live imaging can be used to visualize infections within the central nervous system in real-time.

アフリカトリパノソーマ症の後期感染を検出するための生物発光イメージング

Human African trypanosomiasis (HAT) is a multi-stage disease that manifests in two stages; an early blood stage and a late stage when the parasite invades ...