Source: Davidson, H. W., et al. High-Efficiency Generation of Antigen-Specific Primary Mouse Cytotoxic T Cells for Functional Testing in an Autoimmune Diabetes Model. J. Vis. Exp. (2019).
This video demonstrates a technique for generating antigen-specific chimeric antigen receptor (CAR) T cells through retroviral transduction. Activated murine CD8+ T cells are added to a microwell plate coated with recombinant fibronectin fragments. Retroviral vectors containing transgenic RNA encoding an antigen-specific chimeric antigen receptor (CAR) are then introduced, and the plate is centrifuged to facilitate transduction. After incubation, the transduced cells express antigen-specific CARs on their surface.
1. Generation and validation of single chain Fab antibody (scFab)-CARs.
NOTE: CARs typically contain 3 critical domains—an antigen-targeting domain, a spacer/transmembrane domain, and a cytoplasmic signaling domain. The precise design of each CAR depends on the intended target, and so, apart from the key features of the construct relevant to the generation of the retrovirus, will not be described in detail in this protocol. The overall design of the CARs used for the studies described below is shown in Figure 1. In brief, the targeting domain comprises the entire light chain and variable and CH1 domain of the heavy chain from the parent monoclonal antibody linked by a semi-rigid linker. The spacer/transmembrane domain is from mouse CD28, and the signaling domain is a fusion containing elements from mouse CD28, CD137 (4-1BB), and CD247 (CD3ζ). These elements are assembled by standard molecular biology procedures such as splice overlap polymerase chain reaction (PCR), or the synthesis of an appropriate "gene block". Details of the generation of the mAB287 CAR are contained in Zhang et al. The cDNA sequences can be obtained from the authors upon request.
2. Transfection of viral producer cells (day – 4 to day 3)
NOTE: Retrovirus is produced using Phoenix-ECO cells (see the Table of Materials). Use appropriate precautions for the generation of potentially infectious agents (preferably including a designated Biosafety level 2 (BSL-2) cabinet and separate incubator for culturing transfected/transduced cells).
3. Primary CD8 T cell isolation and activation (day -1 to day 0)
NOTE: Previously, collect CD8 T cells from female nonobese diabetic (NOD) mice at 4–5 weeks, a time point before islet inflammation starts. Handle all the mice following Institutional Animal Care & Use Committee (IACUC) approved protocols. CD8 T cells are enriched from splenocytes using a commercial negative selection kit.
4. T cell activation (Day 0 to 2)
5. Transduction of activated CD8 T cells (days 1 to 3)
NOTE: This protocol uses a spin-transduction method. A centrifuge with a swing-out rotor and tissue culture plate adaptors that is capable of maintaining an internal temperature of 37 °C is required. To ensure maximum efficiency, on the day of transduction pre-warm the centrifuge to 37 °C before collecting the virus.
Figure 1: Schematic of the CAR retroviral construct. The CAR comprises a targeting domain derived from the Fab fragment of a suitable mouse monoclonal antibody, and a spacer/ membrane anchor/ signaling domain from mouse CD28, CD137 and CD247. The synthetic cDNA is inserted into the pMIG-II retroviral expression vector. Restriction endonuclease sites used for generating the mAb287-CAR are shown.
Figure 2: Effect of different plating methods on cell distribution. (Left) Cells pipetted using a swirling motion show an even distribution. (Right) Cells were pipetted directly into the center of the well. Images were captured after spinning at 350 x g for 5 min.
The authors have nothing to disclose.
2-Mercaptoethanol (50mM) | Gibco | 21985-023 | 50 uM |
5' RACE PCR | Clontech | 634859 | |
anti-mouse CD28 antibodies | eBioscience | 14-0281-86 | final concentration at 1µg/ml |
anti-mouse CD3e antibody | eBioscience | 145-2C11 | final concentration at 1µg/ml |
Biotin Rat Anti-Mouse IFN-γ | BD Biosciences | 554410 | Working concentration at 0.5 µg/ml |
BSA | Sigma | A7030 | |
Endo-free Maxi-Prep kit | Qiagen | 12362 | |
Gentamicin | Gibco | 15750-060 | Final 50 µg/ml. |
Heat inactivated FCS | Hyclone | SH30087.03 | Final 10% FCS |
HEPES (100X) | Gibco | 15630-080 | 1X |
Insulin-Transferrin-Selenium-Ethanolamine (ITS 100x) | ThermoFisher | 51500056 | Final concentraion is 1x |
Lipofectamine 2000 | Invitrogen | 11668019 | |
LS Columns | Miltenyi Biotec | 130-042-401 | |
MACS Separation Buffer | Miltenyi Biotec | 130-091-221 | |
Mouse CD8a+ T Cell Isolation Kit | Miletenyi Biotec Inc | 130-104-075 | |
Mouse CD8a+ T Cell Isolation Kit | Miltenyi Biotec | 130-104-075 | |
Opti-MEM medium | ThermoFisher | 31985070 | |
Penicillin-Streptomycin (5000U/ml) | ThermoFisher | 15070063 | 50 U/ml |
Phoenix-ECO cells | ATCC | CRL-3214 | |
Phosphate-buffered saline (PBS) | Gibco | 10010-023 | |
pMIG II | Addgene | 52107 | |
pMSCV-IRES-GFP II | Addgene | 52107 | |
Red cell lysis buffer | Sigma | R7767 | |
RetroNectin | Takara | T100A | Working concentration at 50 µg/ml in PBS |
rhIL-2 (stock concentration 105 IU/ul) | Peprotech | 200-02 | Final concentration at 200 IU/ml |
rmIL-7 ( stock concentration 50ng/ul) | R&D | 407-ML-005 | Final concentration at 0.5ng/ml |
RPMI-1640 | Gibco | 11875-093 | |
Sterile Cell Strainers | Fisher Scientific | 22-363-548 | |
Tryple | Gibco | 12605-028 |
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