A subscription to JoVE is required to view this content. Sign in or start your free trial.
* These authors contributed equally
We present two different staining protocols for NKG2D ligand (NKG2DL) detection in human primary acute myeloid leukemia (AML) samples. The first approach is based on a fusion protein, able to recognize all known and potentially yet unknown ligands, while the second protocol relies on the addition of multiple anti-NKG2DL antibodies.
Within the same patient, absence of NKG2D ligands (NKG2DL) surface expression was shown to distinguish leukemic subpopulations with stem cell properties (so called leukemic stem cells, LSCs) from more differentiated counterpart leukemic cells that lack disease initiation potential although they carry similar leukemia specific genetic mutations. NKG2DL are biochemically highly diverse MHC class I-like self-molecules. Healthy cells in homeostatic conditions generally do not express NKG2DL on the cell surface. Instead, expression of these ligands is induced upon exposure to cellular stress (e.g., oncogenic transformation or infectious stimuli) to trigger elimination of damaged cells via lysis through NKG2D-receptor-expressing immune cells such as natural killer (NK) cells. Interestingly, NKG2DL surface expression is selectively suppressed in LSC subpopulations, allowing these cells to evade NKG2D-mediated immune surveillance. Here, we present a side-by-side analysis of two different flow cytometry methods that allow the investigation of NKG2DL surface expression on cancer cells i.e., a method involving pan-ligand recognition and a method involving staining with multiple antibodies against single ligands. These methods can be used to separate viable NKG2DL negative cellular subpopulations with putative cancer stem cell properties from NKG2DL positive non-LSC.
NK cells are important effectors of the innate immune system that can recognize and eliminate malignant cells or stressed healthy cells (e.g., by a viral infection) without prior antigen stimulation1. This process is tightly regulated via a complex repertoire of activating receptors —such as natural cytotoxicity receptors (NCRs), NKG2D and CD16— and inhibitory receptors that are largely represented by killer immunoglobulin-like receptors (KIRs)2. Binding of KIRs to human leukocyte antigen (HLA) class I molecules on somatic cells ensures self-recognition and conveys NK cell tolerance. On the other hand, absenc....
Patient samples were collected following approval from the Ethics Review Board of the University Hospitals of Basel and Tuebingen.
1. Biotinylation of the NKG2D fusion protein
NOTE: This step is performed with a biotinylation kit (see Table of Materials) according to the manufacturer’s instruction. This step of the protocol must be performed at least 24 h prior to the staining. The biotinylated NKG2D fusion protein should be stored at -20 °.......
Both the protocols presented here allow the enrichment of AML LSC by flow cytometric analyses using CD34, a known marker of LSC17, in combination with NKG2DL surface expression by either utilizing pan-ligand recognition or staining with pooled antibodies against individual ligands. In Figure 1, we show that the analyzed AML samples are positive for CD34 and NKG2DL, but negative subpopulations also exist, which is shown by the presence of four different populations in .......
Here we present two flow cytometric methods that can detect NKG2DL surface expression on human primary AML cells. We show that both detection methods can be used in conjunction with other antibody stainings (e.g., detecting CD34 expression). Similar stainings may also be performed on other primary cell types and cell lines.
We recently showed that the absence of NKG2DL on the surface of AML patient blasts can enrich LSC14. In AML, NKG2DL negative but not NKG2DL positive.......
This study was supported by grants from the Swiss National Science Foundation (179239), the Foundation for Fight Against Cancer (Zuerich), the Wilhelm Sander Foundation to CL (2019.042.1), and the Novartis Foundation for medical-biological research to C.L. Furthermore, this project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 765104. We thank the Flow Cytometry Facility in Basel for support.
....Name | Company | Catalog Number | Comments |
7-amminoactinomycin D (7-AAD) | Invitrogen | A1310 | Viability dye |
96 well plate U bottom | Sarstedt | 833925500 | 96 Well plate for our Flow cytometer |
APC Mouse Anti-Human cd34 | BD | 555824 | Antibody detecting CD34 RRID: AB_398614 |
Bovine Serum Albumin | PanReac AppliChem | A1391,0050 | Component of the staining buffer |
Ethylenediaminetetraacetic acid | Roth | 8043.1 | Component of the staining buffer |
Fetal Calf Serum (FCS) | BioConcept | 2-01F10-I | Component of the supplemented RPMI medium |
FlowJo 10.2 | BD | / | Software enabling data analysis for flow cytometry experiment |
Goat- anti-Rabbit IgG (H+L) Alexa Fluor 488 | Thermo Scientific | A21222 | Secondary antibody detecting the primary antibodies for MICA and MICB RRID: AB_1037853 |
Human NKG2D Fc Chimera Protein, CF | R&D | 1299-NK-050 | Fusion Protein detecting all NKG2DLs RRID: |
Human ULBP-1 Antibody | R&D | AF1380 | Antibody detecting ULBP1 RRID: AB_354765 |
Human ULBP-2/5/6 Antibody | R&D | AF1298 | Antibody detecting ULBP2/5/6 RRID: AB_354725 |
Human ULBP-3 Antibody | R&D | AF1517 | Antibody detecting ULBP3 RRID: AB_354835 |
MICA Polyclonal Antibody | Thermo Scientific | PA5-35346 | Antibody detecting MICA RRID: AB_2552656 |
MICB Polyclonal Antibody | Thermo Scientific | PA5-66698 | Antibody detecting MICB RRID: AB_2663413 |
One-step Antibody Biotinylation Kit 1 strip, for 8 reactions | Miltenyibiotec | 130-093-385 | Biotinylation kit for the NKG2DL fusion protein |
Phosphate Buffered Saline | Sigma Aldrich | D8537-500ML | Component of the staining buffer |
Rabbit anti-Goat IgG (H+L) Alexa Fluor 488 | Thermo Scientific | A11034 | Secondary antibody detecting the primary antibodies for the ULBPs RRID: AB_2576217 |
Rainbow Calibration Particles (8-peaks) 3.0 um | Spherotech Inc. | RCP-30-20A | Beads used for flow cytometry device maintainance |
RPMI medium | Sigma Aldrich | R8758-500ML | Cell culture medium |
RayBright Universal Compensation Beads | Raybiotech | 137-00013-100 | Beads used to create the compensation matrix |
Streptavidin, R-Phycoerythrin Conjugate (SAPE) - 1 mg/mL | Invitrogen | S866 | Seondary step for the biotinylated NKG2DL fusion protein detection |
This article has been published
Video Coming Soon
ABOUT JoVE
Copyright © 2024 MyJoVE Corporation. All rights reserved