Name: a flow cytometry-based cytotoxicity assay for the assessment of human nk cell activity
Uploaded: 2017-08-09T14:00:00.000+00:00
Duration: 6 min 8 s
Description: Watch this Scientific Journal Video about A Flow Cytometry-Based Cytotoxicity Assay for the Assessment of Human NK Cell Activity at JoVE.com

私たちは彼女については原稿を準備するジル ナルシソ、UCLA 免疫遺伝学センターを感謝したいです。

Samples were collected according to the ethical guidelines established by the UCLA Human Research Protection Program and IRB approved.
1. Preparation of reagents
NOTE: Unless otherwise stated, all reagents should be allowed to equilibrate at room temperature prior to use. All reagents must remain sterile.
<ol>
	<li>Prepare a 2x working solution of Tween-20 (i.e., 0.2%) by adding 10&#160;&#181;L of Tween-20 solution to 5 mL of phosphate-buffered saline (PBS) without calcium and magnesium with a p20 pipette.
	<ol>
		<li>Given the high viscosity of Tween-20, take the following steps to ensure accuracy: collect slowly to avoid bubble formation, do not submerge the entire tip to avoid carry-over, and pipette up and down several times in PBS to wash out all Tween-20 from the tip.</li>
	</ol>
	</li>
	<li>Add 2 &#181;L of IL-2 stock solution (2.1E6 IU/mL) to 198 &#181;L of complete media (i.e., 1:100 dilution), which is RPMI with 1% penicillin-streptomycin and 10% fetal bovine serum (FBS), then proceed to an additional 1:100 dilution by adding 2 &#181;L of IL-2 intermediate solution to 198 &#181;L of complete media to prepare a 7x working solution (210 IU/mL).</li>
	<li>Add 2 &#181;L of CFSE stock solution (5 mM) to 500 &#181;L of plain media (RPMI). Vortex, spin down to remove drops from the cap, then proceed with an additional 1:20 dilution by adding 50 &#181;L of the CFSE intermediate solution to 950 &#181;L of plain RPMI to obtain a 2x working solution of 1 &#181;M. Vortex well and keep protected from light.</li>
</ol>
2. Isolation of PBMCs as effector cells
NOTE: This assay has been validated for effective use with total PBMCs from healthy controls. However, it is recommended that NK cell content be verified with each PBMC preparation (Figure 1). Also, the volume of whole blood for collection is based on the frequency of NK cells in peripheral whole blood and this may vary from person to person, particularly between healthy donors and patients.
<ol>
	<li>Collect a minimum of 4 mL of human whole blood in sodium or lithium heparinized blood collection tubes. Store blood samples at room temperature upon collection and use within 30 h of collection.</li>
	<li>Dilute whole blood with 4 mL of PBS (i.e. equal volume of PBS to whole blood).</li>
	<li>Add 4 mL of density gradient solution (see table of materials) to a 15-mL conical tube. Carefully overlay diluted whole blood over the density gradient solution by tilting the tube.</li>
	<li>Centrifuge at 650 x g for 24 min with the brake off.</li>
	<li>Carefully collect the layer of mononuclear cells, which is the thin white layer below the top layer of plasma and platelets, into a new 15-mL conical tube. Bring the volume to 15 mL with PBS.</li>
	<li>Centrifuge at 450 x g for 10 min with the brake on. Aspirate the supernatant and resuspend cells in 0.5 mL of complete media.</li>
	<li>Use an automated cell counter or hemocytometer to count the cells, and adjust the PBMC&#160;concentration to 5x106 cells/mL with complete media.</li>
	<li>Check the NK cell content by flow cytometry (see step 4).</li>
	<li>Start the assay within 30 min. Keep cells at room temperature for up to 10 min, or place in a humidified 5% CO2 incubator at 37 &#176;C until ready for use.</li>
</ol>
3. Isolation of NK cells as effector cells
NOTE: This portion of the protocol is an alternative to using total PBMCs as effector cells. The typical yield from 4 mL of whole blood from a healthy individual is approximately 4x105 NK cells, or approximately 5-15% of PBMCs, though this frequency varies between donors 21. It is recommended that a purity check be performed after the isolation.
<ol>
	<li>Collect a minimum of 4 mL of human whole blood in sodium or lithium heparinized blood collection tubes. Take 50 &#181;L of whole blood to stain as a pre-enrichment sample.</li>
	<li>Add the enrichment cocktail to blood samples at 50 &#181;L/mL (see table of materials). Mix well and incubate for 10 min at room temperature.</li>
	<li>Add an equal volume of PBS + 2% FBS to dilute the sample and gently mix well.</li>
	<li>Add 4 mL of density gradient solution to a 15-mL conical tube. Carefully overlay the diluted sample on top of the density gradient medium.</li>
	<li>Centrifuge at 1,200 x g for 10 min with the brake off.</li>
	<li>Carefully collect the layer of enriched cells into a new 15-mL conical tube. Wash the cells by bringing the volume up to 50 mL with PBS + 2% FBS.</li>
	<li>Centrifuge at 300 x g for 10 min. Discard the supernatant and repeat the wash.</li>
	<li>Aspirate the supernatant and resuspend cells in 0.5 mL of complete media.</li>
	<li>Using an automated cell counter or hemocytometer, count the cells and adjust the concentration to 5x105 cells/mL. Take 50 &#181;L of purified cell suspension to stain as a post-enrichment sample.</li>
	<li>Keep cells at room temperature for up to 10 min, or place in a humidified 5% CO2 incubator at 37 &#176;C until ready for use.</li>
</ol>
4. Immunophenotyping for assessment of NK cell content
<ol>
	<li>Using 50 &#181;L total isolated PBMCs, pre-enrichment whole blood, or purified NK cells, stain with anti-CD56 fluorochrome-conjugated antibody as an NK cell marker. Markers for other cell types and lineages (i.e. CD3+ T cells, CD19+ B cells) may also be included to assess the origin of contamination, if any.</li>
	<li>Incubate for 20 min at 4 &#176;C, and wash by adding 2 mL of PBS + 2% FBS.</li>
	<li>Centrifuge at 450 x g for 5 min.</li>
	<li>For PBMCs or NK cells, aspirate supernatant and resuspend cells in 100 &#181;L of PBS + 2% FBS.</li>
	<li>For whole blood samples, perform red blood cell (RBC) lysis:
	<ol>
		<li>After centrifugation, aspirate the supernatant and resuspend in 2 mL red blood cell lysis buffer (31.75 g of ammonium chloride + 4.16 g of Tris base + 6.65 g of EDTA, dissolved in 5000 mL of deionized water).</li>
		<li>Incubate for 10 min at room temperature.</li>
		<li>Repeat wash twice, aspirate the supernatant, and resuspend lysed sample in 100 &#181;L of PBS + 2% FBS. 
		NOTE: RBC lysis may also be performed prior to staining.</li>
		<li>Proceed with flow cytometric analysis.</li>
	</ol>
	</li>
</ol>
5. Thawing, culturing, and harvesting of K562 target cells
<ol>
	<li>Aliquot 10 mL of complete media into a 15-mL conical tube and allow to warm in a 37 &#176;C water bath. For the thawing and culturing of K562 cells, use only media pre-warmed to 37 &#176;C for all steps.</li>
	<li>Place one vial of frozen K562 cells in the 37 &#176;C water bath until most of it is thawed.</li>
	<li>Transfer the semi-thawed K562 cells to the complete media, pre-warmed to 37 &#176;C, in the 15-mL conical tube. Wash the inside of the cryogenic vial with some pre-warmed media, and add the wash to the 15-mL tube.</li>
	<li>Centrifuge at 140 x g for 7 min with the brake on. Remove the supernatant and resuspend the pellet in 1 mL of complete media.</li>
	<li>Aliquot an appropriate amount of cell suspension to count cells using an automated cell counter or hemocytometer.</li>
	<li>Adjust the concentration to 1x105-2x105 cells/mL&#160;and culture in a humidified 5% CO2 incubator at 37 &#176;C for at least 2 days before use. Maintain the culture at this density range for no longer than 3 months, then thaw a new aliquot.&#160;Never exceed a cell concentration of 1x106 cells/mL in culture.</li>
	<li>For use in the assay, mix the K562 cell culture well with a 10-mL serological pipette and remove an aliquot to count and assess cell viability using an automated cell counter or hemocytometer and Trypan Blue staining.
	<ol>
		<li>If the viability is less than 85%, proceed with the following dead cell removal steps.
		<ol>
			<li>Add 15 mL of density gradient solution to 50-mL conical tubes, as needed. Collect all cells from culture and slowly overlay the cell suspension over the density gradient solution by tilting the tube.</li>
			<li>Centrifuge at 650 x gfor 24 min with brake off. Carefully collect the layer of live cells into a new 15-mL conical tube. Bring the volume to 50 mL with PBS.</li>
			<li>Centrifuge at 450 x g for 10 min with the brake on. Remove the supernatant and resuspend the pellet in 1 mL of complete media. Count the cells and check cell viability (as in 5.7).</li>
			<li>Culture in a humidified 5% CO2 incubator at 37 &#176;C for at least 2 days before use.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Collect 5x105 K562 target cells and centrifuge at 140 x g for 7 min. Aspirate the supernatant and resuspend the cell pellet in 500 &#181;L in media with 1% FBS.</li>
</ol>
6. Labeling of K562 target cells
NOTE: Make sure the K562 cells are well resuspended before adding the CFSE working solution.
<ol>
	<li>Pipette 500 &#181;L of the CFSE working solution to the 500 &#181;L of K562 cells for a final concentration of 0.5 &#181;M. Using the same 1000-1250 &#181;L tip, mix immediately by gently pipetting up and down 3-5 times.</li>
	<li>Incubate in the 37 &#176;C water bath or in a humidified 5% CO2 incubator at 37 &#176;C for 10 min in the dark. 
	NOTE: Since the temperature equilibration lag time is longer in the incubator compared to the water bath, incubation time might need to be adjusted especially for volumes &#62; 1 mL.</li>
	<li>Quench the labeling reaction with 10 mL of complete media for 10 min in the dark at room temperature.</li>
	<li>Centrifuge the labeled K562 cells at 140 x g for 7 min. Remove the supernatant and resuspend in 1 mL of complete media.</li>
	<li>Count the cells using an automated cell counter or hemocytometer and bring the concentration to 1x105 cells/mL in complete media.</li>
	<li>Place cells in a humidified 5% CO2 incubator at 37 &#176;C until ready for use. Cells can be kept at room temperature for up to 10 min, or in in a humidified CO2 incubator at 37 &#176;C until ready for use. Do not refrigerate.</li>
</ol>
7. Plating
NOTE: If NK cells are limiting, the concentration of both K562 and NK cells can be halved, so that half of the cells are plated in the assay. The assay yields comparable results with half the amount of cells (as long as the ratios are kept consistent).
<ol>
	<li>If using total PBMCs, label a 96-well, U-bottom, tissue culture-treated plate for the following conditions per well: (1) Effector (E) : Target (T) = 50 : 1 + IL-2 - positive control for NK cell cytotoxicity; (2) E : T = 50 : 1; (3) E : T = 25 : 1; (4) E : T = 12.5 : 1; (5) E : T = 6.25 : 1; (6) T - target cells only - negative control for K562 death; (7) E - effector cells only; (8) T + Tween - Positive control for K562 death</li>
	<li>If using purified NK cells, label a 96-well, U-bottom, tissue culture treated plate for the following conditions per well: (1) Effector (E) : Target (T) = 5: 1&#160;+ IL-2 - positive control for NK cell cytotoxicity; (2) E : T = 5 : 1; (3) E : T = 2.5 : 1; (4) E : T = 1.25 : 1; (5) E : T = 0.625: 1; (6) T - target cells only - negative control for K562 death; (7) E - effector cells only; (8) T + Tween - positive control for K562 death</li>
	<li>Add 100 &#181;L of complete media to conditions 3, 4, 5, 6, 7. For this and all subsequent steps, (recommended) use a multichannel pipette.</li>
	<li>Add 100 &#181;L of effector cells (PBMCs at 5x106 cells/mL or purified NK cells at 5x105 cells/mL) to conditions 1, 2, 3. Add effector cells for conditions 4-7 by serial dilution. Do not change tips from condition to condition.
	<ol>
		<li>Mix condition 3, take 100 &#181;L, and transfer to condition 4.</li>
		<li>Mix condition 4, take 100 &#181;L, and transfer to condition 5.</li>
		<li>Mix condition 5, take 100 &#181;L, and transfer to condition 7; Condition 6 does not have effector cells.</li>
	</ol>
	</li>
	<li>Add 100 &#181;L of prepared 2x 0.2% Tween working solution to condition 8 (final concentration: 0.1% Tween-20); condition 8 does not have effector cells.</li>
	<li>Add 30 &#181;L of IL-2 working solution to condition 1. IL-2 should be added to the effector cell suspension prior to the addition of target cell suspension (final concentration: 27 IU/mL).</li>
	<li>Add 100 &#181;L of target cells (labeled K562 cells at 1x105 cells/mL) to conditions 1, 2, 3, 4, 5, 6, 8. Condition 7 does not have target cells.</li>
	<li>Mix all wells with a multichannel pipette and centrifuge the plate at 120 x g for 2 min.</li>
	<li>Incubate in a humidified CO2 incubator at 37 &#176;C for 4 h. At the end of the incubation, place the plate on ice and proceed to viability staining within 30 min.</li>
</ol>
8. Staining for viability and acquisition
<ol>
	<li>Prepare dead cell stain (see table of materials) by adding 3 &#181;L of the 5 &#181;M stock solution to 600 &#181;L of PBS.</li>
	<li>Add 50 &#181;L of diluted dead cell stain to each well for a final volume of 250 &#181;L and a final concentration of 0.005 &#181;M. Mix well with a multichannel pipette.</li>
	<li>Proceed with flow cytometric analysis. Using a flow cytometer, collect at least 1,000 events in the target cell gate (Figure 2) for statistically meaningful results.</li>
</ol>

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著者は経済的利害関係の競合を宣言しません。

ここで説明したメソッドは、NK 細胞の細胞傷害活性を評価するために伝統的な51Cr リリース試金する簡単かつコスト効果の高い代替手段を提供します。このメソッドは、機密性の高い、再現と CRA のような前の標準的な方法より手間がかからずと臨床の両方に使用できます、アプリケーションを研究します。
アッセイ作品合計 PBMCs と濃縮の NK 細胞は、細胞集団を浄化するために必要とせず PBMCs を使用するオプションは、患者のサンプルから収集した血液またはいくつかまたは貧しい品質のセルの小さなボリュームを扱う大きなメリットです。この試金は、CFSE と死んだ細胞排除性汚れのみを利用しています。これらの 2 つのパラメーターだけを見て診断を目的として、さらにフローサイトメトリー解析における補償を必要としないという利点を簡潔かつ十分な情報を提供します。
このメソッドは、基本的な NK 細胞生物学を研究し、新規 NK 細胞標的療法をテストにも使用できます。この点では、流れの cytometers の拡大機能は、このアッセイは、NK 細胞と活性多項目分析のない CRA のような試金で実現されていたことに汎用性の非常に貴重な要素をご紹介します。研究者のニーズに合わせて代替細胞トラッキングと生存率染料は、他のチャネルで蛍光剤があります。
このプロトコルは、原型の NK 細胞ターゲット細胞 k562 の使用に最適です。ただし、それは HL 60、Daudi、U937 らじおなどの NK 細胞活性に対する感度の度合いと代替懸濁液ターゲット細胞ラインに合わせることができます。この点では、異なると各流れの cytometer 細胞が蛍光ラベルをかかる場合があります、蛍光色素とターゲット細胞ラベリングに使用する血清の濃度を各ターゲット セル行用に最適化するして必要がありますに注意する重要です。通常、ラベル付け中に血清を使用して避けるためにお勧めしますが、我々 は 2 つの理由の FBS の 0.5% とわずかな焼入れを選びました。最初に、ターゲット セル ストレスを減らす、従って背景を汚す;第二に、それは従って測定の再現性を助ける日常の設定の調整を必要とせず CFSE 信号の流れの cytometer の検出の適切な範囲内をもたらします。追加議定書のバリエーションは、異なる E:T 比と異なる活性化条件にアッセイを適応するインキュベーション時間のテストなどがあります。長期間自然放出の増加9,16が発生する傾向にあるものの、エフェクターと NK 細胞毒性をテストに標的細胞の共培養の期間が歴史的に 4-16 h からであった。私たちのメソッドで長い潜伏も失われる可能性殺害または増殖による標的細胞によってラベリングのこれらの蛍光染料は細胞分裂時に希釈したよう。つまり、タイム ウィンドウの下端に孵化が一般に好ましい、一晩培養6,16,22を超えない。
変数このアッセイの結果を及ぼしますノートを取ることが重要です。私たちの経験では、K562 標的細胞が温度変化に特に敏感です。したがって、K562 細胞ないする冷蔵しますが、むしろ室温で保管か、使用前に 37 ° C で加湿 CO2インキュベーターに配置されます。同じ理由で、プロトコルに記載されているすべての試薬を適切な温度にくるべきだった。これらの細胞に影響を与える別のパラメーターは遠心分離の速度は、細胞ストレスを最小限に抑えるために減るべきであります。また、エフェクター/ターゲットの作製と 30 分以内に共培養開始までのタイムラグを制限する最大の殺害の活動を確保し、アッセイの再現性に不可欠です。同様に、CFSE 信号は一般的に堅牢なので、正確な分注、セルと正確な潜伏の適切な混合時ラベリングと焼入れ、染色の整合性を確保することが重要です。最後に、NK 細胞の細胞傷害性機能は健常者にも非常に多様し、発達段階、性別、年齢、重量23,24,などの要因の数に影響されます25 。さらを健常者の 30% に大幅に削減や細胞機能の完全な損失場合表示採血後 24 時間以上のテストします。したがって、それは新鮮な精製使用 PBMCs または NK 細胞を可能な限り勧め。

An erratum was issued for: <a href="https://www-jove-com.bdigitaluss.remotexs.co/video/56191/a-flow-cytometry-based-cytotoxicity-assay-for-assessment-human-nk">A Flow Cytometry-Based Cytotoxicity Assay for the Assessment of Human NK Cell Activity</a>. Figure 4 has been corrected to show background-corrected data.
Figure 4 was updated from:
<img alt="Figure 4" src="/files/ftp_upload/56191/56191fig4v1.jpg" />
to:
<img alt="Figure 4" src="/files/ftp_upload/56191/56191fig4v2.jpg" />

An erratum was issued for: <a href="https://www-jove-com.bdigitaluss.remotexs.co/video/56191/a-flow-cytometry-based-cytotoxicity-assay-for-assessment-human-nk">A Flow Cytometry-Based Cytotoxicity Assay for the Assessment of Human NK Cell Activity</a>. Figure 4 has been corrected to show background-corrected data.

Erratum: A Flow Cytometry-Based Cytotoxicity Assay for the Assessment of Human NK Cell Activity

ナチュラル キラー (NK) 細胞は、人間の生得的なリンパ球批判的に他の病原性の脅威1,2トランス ホーム細胞、ウイルス感染細胞の排除に関与の洗練されたサブセットです。NK 細胞溶解顆粒細胞傷害性タンパク質、パーフォリンなど granzymes の家します。起動時に、NK 細胞は直接ターゲット セル換散とサイトカインとケモカインの放出とともにアポトーシスの結果これらの細胞傷害性の分子がリリースされたローカルという免疫学のシナプスと呼ばれる、ターゲットとの複雑な相互作用を形成し、最終的に、炎症の誘導で1,3,4の状態します。
NK 細胞の活性化を含む複雑な文字列を活性化と抑制相互 NK 細胞受容体とリガンドの堅く調整されたシステムの形成、標的細胞の表面に発現します。NK 細胞の活性化の最も研究のメカニズムの 1 つは、「行方不明自己」です。確かに組織適合性の複雑な (MHC)、または人間の白血球の抗原 (HLA) 分子を主要なクラスの検出の欠如感染または細胞トリガー NK 細胞障害活性を変換します。腫瘍、ウイルス感染細胞レセプター一般的に NK になる T 細胞性免疫能を脱出するこれらの抗原細胞ターゲット1,3,4。
NK 細胞機能の評価は主に脱顆粒や細胞毒性に分類の試金。ただし、脱顆粒関連マーカー CD107a の流れフローサイトメトリー検出などの脱顆粒の試金は NK 細胞の活性化とそれらの究極の機能は、ターゲット セル5,6,7,8の直接の殺害を示すのみ。したがって、この制限は細胞毒性の試金に指示しより直接的代替として調査官を集めています。
長年「ゴールド スタンダード」T および NK 細胞の細胞媒介性細胞傷害活性を評価するため、クロム リリース試金 (CRA)。CRA は、放射能によって51Cr を用いた標的細胞のラベリングとエフェクター細胞にそれらをインキュベート共同に含まれます。この試金は蛋白質バインド51Cr 培養上清をガンマを数えることで測定することができますリリースでそのセル換散の結果主義が染み込んでください。効果的、このアッセイはさまざまな理由のため問題となる: 困難な標準化 - ことが全体で非現実的な9,10 51Cr の自発的なリリースと放射性51Cr の処分処理高材料費。
非放射性アッセイ、蛍光標識、酵素リリースも生物発光などの数から、CRA 111412,13,,に代わるものとして開発されています。ここで NK 細胞細胞毒性活性 K562 標的細胞に簡単な敏感なと再現性のある測定用フロー フローサイトメトリーを用いた手法について述べる。K562 細胞は、人間 erythroleukemic セル HLA クラスの発現低下と私と NK 細胞媒介性細胞傷害15に特に敏感になる賦活の NK の受容器のための ligands の高められた表現です。このアッセイ K562 細胞 carboxyfluorescein ジアセテート サクシニミジルエステル (CFSE) があらかじめ付いていますいずれか末梢血単核球 (Pbmc) の様々 な比率で共培養や NK 細胞1を精製しました。CFSE はエフェクター NK 細胞16,17から標的細胞の判別ができる安定した、蛋白結合蛍光染料です。共培養後核酸染色、特に死んだ細胞の膜を浸透、殺された標的細胞 (材料の表を参照) を識別するために使用されます。流れの cytometer 死者 (すなわち、汚れ +) の割合を決定するために、サンプルを集録し、CFSE + 標的細胞。
この試金は、機能やクラシックの NK 細胞の欠乏を引き起こす約 30 の既知の欠陥がある NK 細胞コンパートメントに影響を与えるイネの欠陥、プライマリまたはセカンダリの血球貪食症候群、ルーチンの診断スクリーニングとして使用できます。また、再発、重度のヘルペス ウイルス感染症、造血幹細胞移植またはポスト免疫調節療法18,19、20、次免疫再構築を評価するための基本的な研究アプリケーションのホストのため患者の NK 細胞活性を調査することをお勧めします。

<table><tbody><tr><td>Phosphate-buffered Saline (1x, w/o Ca2+ and Mg2+)</td><td>Corning (Cellgro)</td><td>21-040-CM</td><td></td></tr><tr><td>Ficoll-Paque PLUS</td><td>GE Healthcare</td><td>17-1440-02</td><td></td></tr><tr><td>Tween-20</td><td>Sigma</td><td>BP337-100</td><td></td></tr><tr><td>RPMI 1640 Media</td><td>Corning (Cellgro)</td><td>10-040-CV</td><td></td></tr><tr><td>Heat-inactivated Fetal Bovine Serum</td><td>Omega Scientific</td><td>FB-02</td><td></td></tr><tr><td>Penicillin Streptomycin</td><td>Life Technologies</td><td>15140-163</td><td>Stock solution at 10,000 U/mL</td></tr><tr><td>IL-2</td><td>R&amp;amp;D Systems</td><td>202-IL-050</td><td>Lyophilized from a 0.2 &amp;mu;m filtered solution in Acetonitrile and TFA with BSA as a carrier protein. Reconstitute with 500 ul at 100 &amp;mu;g/mL in sterile 100 mM Acetic Acid containing at least 0.1% bovine serum albumin (2.1x10E6 IU/ml)</td></tr><tr><td>K562 Cells</td><td>ATCC</td><td>CCL-243</td><td>Cancer cell line&amp;nbsp;</td></tr><tr><td>T-75 cell culture flasks</td><td>Corning</td><td>431464</td><td></td></tr><tr><td>CFSE cell proliferation kit</td><td>Life Technologies (CellTrace)</td><td>C34554</td><td>Reconstitute I vial with 18 ul DMSO to prepare a 5mM stock solution. Do not freeze/thaw.</td></tr><tr><td>Sytox Red</td><td>Life Technologies</td><td>S34859</td><td>Stock solution is provided at 5 &amp;mu;M in 1 mL DMSO. The DMSO solution may be subjected to multiple freeze-thaw cycles without reagent degradation.</td></tr><tr><td>Sodium/lithium heparin blood collection tubes</td><td>BD</td><td>02-687-95</td><td></td></tr><tr><td>U-bottom 96-well plate</td><td>Corning</td><td>CLS3897</td><td></td></tr><tr><td>Serological pipettes</td><td>BD Falcon</td><td></td><td></td></tr><tr><td>Polystyrene round-bottom tubes (5mL)</td><td>BD Falcon</td><td>14959-5</td><td></td></tr><tr><td>50 mL polypropylene conical tube</td><td>BD Falcon</td><td>352070</td><td></td></tr><tr><td>15 mL polypropylene conical tube</td><td>BD Falcon</td><td>352097</td><td></td></tr><tr><td>Reagent reservoir</td><td>USA Scientific</td><td>2321-2230</td><td></td></tr><tr><td>Human NK cell enrichment cocktail</td><td>StemCell Technologies (RosetteSep)</td><td>15065</td><td></td></tr></tbody></table>

a flow cytometry-based cytotoxicity assay for the assessment of human nk cell activity

自然免疫系のエフェクター リンパ球のナチュラル キラー (NK) 細胞として知られている重要な役割宿主防御において異常な細胞、特に腫瘍を排除し、ウイルス感染細胞に対する。他の病理学の条件のホストとともに、約 30 知られているイネの欠陥では、機能または古典的な NK 細胞欠乏症を引き起こす、けんしょうの減少や細胞傷害活性を欠席します。歴史的には、細胞毒性を面倒な高価な潜在的に有害である放射性の方法で調べた。この資料では、合理化された、臨床応用可能な流れ cytometry ベースの NK 細胞の細胞傷害活性を定量化する方法について説明します。この分析では、末梢血単核球 (PBMCs) または NK 細胞純化は、異なる比率で共存培養 NK 細胞性細胞毒性 (NKCC) に敏感であると知られているターゲット腫瘍細胞株。標的細胞はエフェクター細胞 (NK 細胞) から差別を許可する蛍光色素をあらかじめラベルを。潜伏期間後殺された標的細胞は、死んだ細胞に浸透する具体的には核酸の汚れによって識別されます。このメソッドは、診断や研究用途との両方、フローサイトメトリーのマルチパラ メーター機能のおかげで影響を受けやすい可能性のある NK 細胞の表現型と機能のより深い分析を可能にする利点があります。

アッセイをセットアップする前に NK 細胞内容が好みのエフェクター人口で評価されることを強くお勧めします。図 1は、典型的な CD56 染色 (ライトブルー) の前に示しています (赤) NK 細胞濃縮後。NK 細胞は、PBMCs の最大 15% を占めるし、濃縮後の少なくとも 80% 純粋なべきであります。
このアッセイのフローサイトメトリーによる解析を含む 2 つのパラメーターの検出: CFSE、FITC; と同じチャネルの検出死んだ細胞の染色、APC (図 2 a、B) と同じチャネルで検出。データ集録、データを分析する図 2のゲートの戦略が使用されます。死者 (すなわち、死んだ細胞染色 +) K562 標的細胞はターゲット人口の内で殺された細胞の % を提供する CFSE + 人口のうちゲートが。
制御条件自体と、個別のコンポーネントに分析の有効性を確保する上で重要であります。有効と見なされる試金のための順序で次の制御条件 (6-8) に期待されるべき: ターゲットセルの間のみ (条件6) 細胞死になります &#60; 15% (図 3 a)。エフェクター細胞のみ (条件7)、および細胞死であるべき CFSE 信号を検出する必要があります &#60; 5% (図 3 b)。トゥイーンを介した標的細胞 (の状態8) の殺害、細胞死がする必要があります &#62; 85% (図 3)。
ほとんどの殺害の活動が低下している NK 細胞機能の欠陥を有する患者を予想またはすべての比は、健康な人と比較してテストします。健康なドナーと図 4の患者細胞の並列は、エフェクター ターゲット細胞比率の減少ターゲット細胞死における差分、大幅に削減を示しています。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56191/56191fig1.jpg"> 
図 1: NK エフェクター集団内でセルの内容の評価します。染色後の代表的なヒストグラム PBMCs (水色) を合計または CD56 の NK 細胞 (赤) を精製しました。<a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/56191/56191fig1large.jpg" target="_blank">この図の拡大版を表示するのにはここをクリックしてください</a>。
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56191/56191fig2.jpg"> 
図 2: 標的細胞の検出のための戦略をゲーティングします。A) FITC/SSC-A プロットの最初のゲートを設定。K562 細胞は、CFSE + イベントとしてゲートです。B)死んだ K562 細胞 (すなわち、死んだ細胞の陽性染色) CFSE + ターゲット細胞集団内で後続の APC/SSC-A プロットとしているゲートします。<a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/56191/56191fig2large.jpg" target="_blank">この図の拡大版を表示するのにはここをクリックしてください</a>。
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/56191/56191fig3.jpg"> 
図 3: 代表的なデータの条件を制御します。A)率死んだ細胞染色 + K562 細胞 CFSE + ゲート (図 2のように戦略をゲート) 内条件6 (ターゲット セルのみ) - ネガティブ コントロール K562 細胞死の。B) CFSE と死んだ細胞を染色条件7の検出 (エフェクター細胞のみ - 合計 PBMCs)。C)率死んだ細胞染色 + K562 細胞 CFSE + ゲート (図 2のように戦略をゲート) 内条件8 (ターゲット セル + トゥイーン) - 肯定的な制御 K562 細胞死の。<a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/56191/56191fig3large.jpg" target="_blank">この図の拡大版を表示するのにはここをクリックしてください</a>。
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/56191/56191fig4.jpg"> 
図 4: さまざまなエフェクター ターゲット細胞比率の希釈効果の代表的なデータです。テスト ターゲット: エフェクター細胞比は次のとおりです: 50 分の 1、25: 1;12.5: 1;6.25:1. データは背景 (条件 #6)-削除します。<a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/56191/56191fig4large.jpg" target="_blank">この図の拡大版を表示するのにはここをクリックしてください</a>。
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>サンプル</td>
			<td>条件</td>
			<td>エフェクター (E): ターゲット (T)</td>
		</tr>
		<tr>
			<td rowspan="8">PBMCs</td>
			<td>1 - NK 細胞障害活性の肯定的な制御</td>
			<td>50:1 + IL-2</td>
		</tr>
		<tr>
			<td>2</td>
			<td>50:1</td>
		</tr>
		<tr>
			<td>3</td>
			<td>25:1</td>
		</tr>
		<tr>
			<td>4</td>
			<td>12.5: 1</td>
		</tr>
		<tr>
			<td>5</td>
			<td>6.25: 1</td>
		</tr>
		<tr>
			<td>6</td>
			<td>T のみ</td>
		</tr>
		<tr>
			<td>7 - K562 死ネガティブ コントロール</td>
			<td>E のみ</td>
		</tr>
		<tr>
			<td>8 - K562 死肯定的な制御</td>
			<td>T + トゥイーン</td>
		</tr>
		<tr>
			<td rowspan="8">NK 細胞 (精製)</td>
			<td>1 - NK 細胞障害活性の肯定的な制御</td>
			<td>5:1 + IL-2</td>
		</tr>
		<tr>
			<td>2</td>
			<td>5:1</td>
		</tr>
		<tr>
			<td>3</td>
			<td>2.5: 1</td>
		</tr>
		<tr>
			<td>4</td>
			<td>1.25: 1</td>
		</tr>
		<tr>
			<td>5</td>
			<td>0.625: 1</td>
		</tr>
		<tr>
			<td>6</td>
			<td>T のみ</td>
		</tr>
		<tr>
			<td>7 - K562 死ネガティブ コントロール</td>
			<td>E のみ</td>
		</tr>
		<tr>
			<td>8 - K562 死肯定的な制御</td>
			<td>T + トゥイーン</td>
		</tr>
	</tbody>
</table>
テーブル 1

Watch this Scientific Journal Video about A Flow Cytometry-Based Cytotoxicity Assay for the Assessment of Human NK Cell Activity at JoVE.com

A Flow Cytometry-Based Cytotoxicity Assay for the Assessment of Human NK Cell Activity

流れ cytometry ベースの人間のナチュラル キラー細胞の細胞傷害活性を定量的に決定する方法を示しています。

ヒト NK 細胞活性の評価の流れのフローサイトメトリーを用いた細胞毒性の試金

Within the innate immune system, effector lymphocytes known as natural killer (NK) cells play an essential role in host defense against aberrant cells, ...

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Universidad San Sebastian

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JoVE Journal

Immunology and Infection

23.7K ビュー.  University of California, Los Angeles. 流れ cytometry ベースの人間のナチュラル キラー細胞の細胞傷害活性を定量的に決定する方法を示しています。

ビデオ: A Flow Cytometry-Based Cytotoxicity Assay for the Assessment of Human NK Cell Activity

Expansion, Purification, and Functional Assessment of Human Peripheral Blood NK Cells 

Natural killer (NK) cells play an important role in immune surveillance against a variety of infectious microorganisms and tumors. Limited availability of NK cells and ability to expand in vitro has restricted development of NK cell immunotherapy. Here we describe a method to efficiently expand vast quantities of functional NK cells ex vivo using K562 cells expressing membrane-bound IL21, as an artificial antigen-presenting cell (aAPC).
NK cell adoptive therapies to date have utilized a cell product obtained by steady-state leukapheresis of the donor followed by depletion of T cells or positive selection of NK cells. The product is usually activated in IL-2 overnight and then administered the following day 1. Because of the low frequency of NK cells in peripheral blood, relatively small numbers of NK cells have been delivered in clinical trials.
The inability to propagate NK cells in vitro has been the limiting factor for generating sufficient cell numbers for optimal clinical outcome. Some expansion of NK cells (5-10 fold over 1-2 weeks) has be achieved through high-dose IL-2 alone 2. Activation of autologous T cells can mediate NK cell expansion, presumably also through release of local cytokine 3. Support with mesenchymal stroma or artificial antigen presenting cells (aAPCs) can support the expansion of NK cells from both peripheral blood and cord blood 4. Combined NKp46 and CD2 activation by antibody-coated beads is currently marketed for NK cell expansion (Miltenyi Biotec, Auburn CA), resulting in approximately 100-fold expansion in 21 days.
Clinical trials using aAPC-expanded or -activated NK cells are underway, one using leukemic cell line CTV-1 to prime and activate NK cells5 without significant expansion. A second trial utilizes EBV-LCL for NK cell expansion, achieving a mean 490-fold expansion in 21 days6. The third utilizes a K562-based aAPC transduced with 4-1BBL (CD137L) and membrane-bound IL-15 (mIL-15)7, which achieved a mean NK expansion 277-fold in 21 days. Although, the NK cells expanded using K562-41BBL-mIL15 aAPC are highly cytotoxic in vitro and in vivo compared to unexpanded NK cells, and participate in ADCC, their proliferation is limited by senescence attributed to telomere shortening8. More recently a 350-fold expansion of NK cells was reported using K562 expressing MICA, 4-1BBL and IL159.
Our method of NK cell expansion described herein produces rapid proliferation of NK cells without senescence achieving a median 21,000-fold expansion in 21 days.

Expansion, Purification, and Functional Assessment of Human Peripheral Blood NK Cells

Here we describe a method to efficiently expand and purify large numbers of human NK cells and assess their function.

拡大、精製、及びヒト末梢血NK細胞の機能的評価

Natural killer (NK) cells play an important role in immune surveillance against a variety of infectious microorganisms and tumors. Limited availability of ...

免疫・感染学

Preparation and Use of HIV-1 Infected Primary CD4+ T-Cells as Target Cells in Natural Killer Cell Cytotoxic Assays

Natural killer (NK) cells are a vital component of the innate immune response to virus-infected cells. It is important to understand the ability of NK cells to recognize and lyse HIV-1 infected cells because identifying any aberrancy in NK cell function against HIV-infected cells could potentially lead to therapies that would enhance their cytolytic activity. There is a need to use HIV-infected primary T-cell blasts as target cells rather then infected-T-cell lines in the cytotoxicity assays. T-cell lines, even without infection, are quite susceptible to NK cell lysis. Furthermore, it is necessary to use autologous primary cells to prevent major histocompatibility complex class I mismatches between the target and effector cell that will result in lysis. Early studies evaluating NK cell cytolytic responses to primary HIV-infected cells failed to show significant killing of the infected cells 1,2. However, using HIV-1 infected primary T-cells as target cells in NK cell functional assays has been difficult due the presence of contaminating uninfected cells 3. This inconsistent infected cell to uninfected cell ratio will result in variation in NK cell killing between samples that may not be due to variability in donor NK cell function. Thus, it would be beneficial to work with a purified infected cell population in order to standardize the effector to target cell ratios between experiments 3,4. Here we demonstrate the isolation of a highly purified population of HIV-1 infected cells by taking advantage of HIV-1's ability to down-modulate CD4 on infected cells and the availability of commercial kits to remove dead or dying cells 3-6. The purified infected primary T-cell blasts can then be used as targets in either a degranulation or cytotoxic assay with purified NK cells as the effector population 5-7. Use of NK cells as effectors in a degranulation assay evaluates the ability of an NK cell to release the lytic contents of specialized lysosomes 8 called "cytolytic granules". By staining with a fluorochrome conjugated antibody against CD107a, a lysosomal membrane protein that becomes expressed on the NK cell surface when the cytolytic granules fuse to the plasma membrane, we can determine what percentage of NK cells degranulate in response to target cell recognition. Alternatively, NK cell lytic activity can be evaluated in a cytotoxic assay that allows for the determination of the percentage of target cells lysed by release of 51Cr from within the target cell in the presence of NK cells.

Cytotoxicity assays to measure natural killer cell lytic responses to HIV-infected cells is limited by the purity of the target cells. We demonstrate here the isolation of a highly purified population of HIV-1 infected primary T-cell blasts by taking advantage of HIV-1 s ability to down-modulate CD4.

ナチュラルキラー細胞傷害性アッセイにおけるHIV - 1感染プライマリCD4 + T細胞を標的細胞としての準備と使用

 Natural killer (NK) cells are a vital component of the innate immune response to virus-infected cells. It is important to understand the ability of NK ...

Cell-based Flow Cytometry Assay to Measure Cytotoxic Activity

Cytolytic activity of CD8+ T cells is rarely evaluated. We describe here a new cell-based assay to measure the capacity of antigen-specific CD8+ T cells to kill CD4+ T cells loaded with their cognate peptide. Target CD4+ T cells are divided into two populations, labeled with two different concentrations of CFSE. One population is pulsed with the peptide of interest (CFSE-low) while the other remains un-pulsed (CFSE-high). Pulsed and un-pulsed CD4+ T cells are mixed at an equal ratio and incubated with an increasing number of purified CD8+ T cells. The specific killing of autologous target CD4+ T cells is analyzed by flow cytometry after coculture with CD8+ T cells containing the antigen-specific effector CD8+ T cells detected by peptide/MHCI tetramer staining. The specific lysis of target CD4+ T cells measured at different effector versus target ratios, allows for the calculation of lytic units, LU30/106 cells. This simple and straightforward assay allows for the accurate measurement of the intrinsic capacity of CD8+ T cells to kill target CD4+ T cells.

This protocol describes a sensitive, cell-based cytotoxicity assay. By enumerating the decrease in frequency of live target CD4+ T cells in the presence of an increasing number of effector CD8+ T cells, this assay allows for the direct assessment of cytolytic activity of antigen-specific CD8+ T cells.

Cytolytic activity of CD8+ T cells is rarely evaluated. We describe here a new cell-based assay to measure the capacity of antigen-specific CD8+ T cells ...

Flow Cytometry-based Assay for the Monitoring of NK Cell Functions

Natural killer (NK) cells are an important part of the human tumor immune surveillance system. NK cells are able to distinguish between healthy and virus-infected or malignantly transformed cells due to a set of germline encoded inhibitory and activating receptors. Upon virus or tumor cell recognition a variety of different NK cell functions are initiated including cytotoxicity against the target cell as well as cytokine and chemokine production leading to the activation of other immune cells. It has been demonstrated that accurate NK cell functions are crucial for the treatment outcome of different virus infections and malignant diseases. Here a simple and reliable method is described to analyze different NK cell functions using a flow cytometry-based assay. NK cell functions can be evaluated not only for the whole NK cell population, but also for different NK cell subsets. This technique enables scientists to easily study NK cell functions in healthy donors or patients in order to reveal their impact on different malignancies and to further discover new therapeutic strategies.

A simple and reliable method is described here to analyze a set of NK cell functions such as degranulation, cytokine and chemokine production within different NK cell subsets.

NK細胞の機能を監視するためのサイトメトリーに基づくアッセイを流します

Natural killer (NK) cells are an important part of the human tumor immune surveillance system. NK cells are able to distinguish between healthy and ...

Flow Cytometric Analysis of Natural Killer Cell Lytic Activity in Human Whole Blood

NK cell cytotoxicity is a widely used measure to determine the effect of outside intervention on NK cell function. However, the accuracy and reproducibility of this assay can be considered unstable, either because of user&#39;s errors or because of the sensitivity of NK cells to experimental manipulation. To eliminate these issues, a workflow that reduces them to a minimum was established and is presented here. To illustrate, we obtained blood samples, at various time points, from runners (n = 4) that were submitted to an intense bout of exercise. First, NK cells are simultaneously identified and isolated through CD56 tagging and magnetic-based sorting, directly from whole blood and from as little as one milliliter. The sorted NK cells are removed of any reagent or capping antibodies. They can be counted in order to establish an accurate NK cell count per milliliter of blood. Secondly, the sorted NK cells (effectors cells or E) can be mixed with 3,3&#39;-Diotadecyloxacarbocyanine Perchlorate (DiO) tagged K562 cells (target cells or T) at an assay-optimal 1:5 T:E ratio, and analyzed using an imaging flow-cytometer that allows for the visualization of each event and the elimination of any false positive or false negatives (such as doublets or effector cells). This workflow can be completed in about 4 h, and allows for very stable results even when working with human samples. When available, research teams can test several experimental interventions in human subjects, and compare measurements across several time points without compromising the data&#39;s integrity.

This work describes an advanced workflow for the accurate and fast determination of NK (Natural Killer) cell count and NK cell cytotoxicity in human blood samples.

ヒト全血中のナチュラルキラー細胞溶解活性のフローサイトメトリー分析

NK cell cytotoxicity is a widely used measure to determine the effect of outside intervention on NK cell function. However, the accuracy and ...

A Plate-based Cytotoxicity Assay for the Assessment of Rat Placental Natural Killer Cell Cytolytic Function

It is well known that decidual natural killer (NK) cells play a critical role in establishment and maintenance of normal pregnancy. Recent studies have demonstrated an altered population of circulating and decidual NK cells in women who suffer from adverse pregnancy complications such as recurrent miscarriage and preeclampsia. Studies from our group have shown that hypertension in pregnancy is associated with an increased population of activated NK cells in the placenta based on the expression of surface activation markers. This manuscript provides a detailed protocol to assess the cytotoxic function of NK cells isolated from placentas in a preeclampsia-like animal model of surgically induced placental ischemia. The following steps are described in detail: generation of single cell suspension, NK cell isolation, ex vivo stimulation, effector:target cell co-culture, and the cytotoxicity assay.

Here, we provide a detailed methodology to isolate and assess cytotoxic function of natural killer cells from placentas by a colorimetric plate assay. The reduced uterine perfusion pressure rat model of placental ischemia was chosen to demonstrate the antibody-mediated isolation and assessment of the cytotoxic function of natural killer cells.

ラット胎盤ナチュラルキラー細胞細胞溶解機能の評価のためのプレートベースの細胞毒性アッセイ

It is well known that decidual natural killer (NK) cells play a critical role in establishment and maintenance of normal pregnancy. Recent studies have ...

Assessment of Human Natural Killer Cell Events Driven by Fc&#947;RIIIa Engagement in the Presence of Therapeutic Antibodies

One mechanism of action for clinical efficacy by therapeutic antibodies is the promotion of immune-related functions, such as cytokine secretion and cytotoxicity, driven by Fc&#947;RIIIa (CD16) expressed on natural killer (NK) cells. These observations have led to research focusing on methods to increase Fc receptor-mediated events, which include removal of a fucose moiety found on the Fc portion of the antibody. Further studies have elucidated the mechanistic changes in signaling, cellular processes, and cytotoxic characteristics that increase ADCC activity with afucosylated antibodies. Additionally, other studies have shown the potential benefits of these antibodies in combination with small molecule inhibitors. These experiments demonstrated the molecular and cellular mechanisms underlying the benefits of using afucosylated antibodies in combination settings. Many of these observations were based on an artificial in vitro activation assay in which the Fc&#947;RIIIa on human NK cells was activated by therapeutic antibodies. This assay provided the flexibility to study downstream effector NK cell functions, such as cytokine production and degranulation. In addition, this assay has been used to interrogate signaling pathways and identify molecules that can be modulated or used as biomarkers. Finally, other therapeutic molecules (i.e., small molecule inhibitors) have been added to the system to provide insights into the combination of these therapeutics with therapeutic antibodies, which is essential in the current clinical space. This manuscript aims to provide a technical foundation for performing this artificial human NK cell activation assay. The protocol demonstrates key steps for cell activation as well as potential downstream applications that range from functional readouts to more mechanistic observations.

A protocol for studying Fc&#947;RIIIa-driven events by therapeutic antibodies in human natural killer cells is described here. This artificial stimulation platform permits the interrogation of downstream effector functions such as degranulation, chemokine/cytokine production, and signaling pathways mediated by the Fc&#947;RIIIa and Fc portions of antibodies involved in binding.

治療抗体の存在下におけるFcγRIIIa関与によるヒトナチュラルキラー細胞事象の評価

One mechanism of action for clinical efficacy by therapeutic antibodies is the promotion of immune-related functions, such as cytokine secretion and ...

Measurement of Natural Killer Cell-Mediated Cytotoxicity and Migration in the Context of Hepatic Tumor Cells

Natural killer (NK) cells are a subset of the cytotoxic lymphocyte population of the innate immune system and participate as a first line of defense by clearing pathogen-infected, malignant, and stressed cells. The ability of NK cells to eradicate cancer cells makes them an important tool in the fight against cancer. Several new immune-based therapies are under investigation for cancer treatment which rely either on enhancing NK cell activity or increasing the sensitivity of cancer cells to NK cell-mediated eradication. However, to effectively develop these therapeutic approaches, cost-effective in vitro assays to monitor NK cell-mediated cytotoxicity and migration are also needed. Here, we present two in vitro protocols that can reliably and reproducibly monitor the effect of NK-cell cytotoxicity on cancer cells (or other target cells). These protocols are non-radioactivity-based, simple to set up, and can be scaled up for high-throughput screening. We also present a flow cytometry-based protocol to quantitatively monitor NK cell migration, which can also be scaled up for high-throughput screening. Collectively, these three protocols can be used to monitor key aspects of NK cell activity that are necessary for the cells&#39; ability to eradicate dysfunctional target cells.

Evasion of natural killer (NK) cell-mediated eradication by cancer cells is important for cancer initiation and progression. Here, we present two non-radioactivity-based protocols to evaluate NK cell-mediated cytotoxicity toward hepatic tumor cells. Additionally, a third protocol is presented to analyze NK cell migration.

肝腫瘍細胞の文脈における自然キラー細胞媒介性細胞毒性と遊性の測定

Natural killer (NK) cells are a subset of the cytotoxic lymphocyte population of the innate immune system and participate as a first line of defense by ...

医学

Calcein Acetoxymethyl Staining to Evaluate Natural Killer Cell-Mediated Cytotoxicity toward Cancer Cells

Source: Chava, S. et al., <a href="https://app-jove-com.bdigitaluss.remotexs.co/v/60714">Measurement of Natural Killer Cell-Mediated Cytotoxicity and Migration in the Context of Hepatic Tumor Cells.</a> J. Vis. Exp. (2020)
This video demonstrates an assay to measure the cytotoxicity of natural killer cells against cancer cells using the Calcein AM stain. The reduced number of fluorescent cancer cells following co-culture with natural killer cells indicates natural killer cell-mediated cytotoxicity toward cancer cells.

がん細胞に対するナチュラルキラー細胞媒介性細胞毒性を評価するためのカルセインアセトキシメチル染色

Source: Chava, S. et al., Measurement of Natural Killer Cell-Mediated Cytotoxicity and Migration in the Context of Hepatic Tumor Cells. J. Vis. Exp. ...

JoVE Encyclopedia of Experiments

免疫学

免疫診断

画像化および視覚化技術

Natural Killer Cell-Mediated Cytotoxicity Assay Sample Preparation for Flow Cytometric Analysis

Source: McBride, J. E., et al. <a href="https://app-jove-com.bdigitaluss.remotexs.co/v/54779">Flow Cytometric Analysis of Natural Killer Cell Lytic Activity in Human Whole Blood.</a> J. Vis. Exp. (2017).
This video demonstrates the lytic activity of natural killer cells against fluorescently-stained target cells. The method enables NK cell-induced cytotoxicity measurement by staining dead cells and using a flow cytometer to quantify live and dead target cells.