Supplementary Materialscells-09-00998-s001. were established using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9). The sgRNA/Cas9 expression vectors designed precisely disrupted the target region of PD-1 and inhibited the expression of PD-1 in EvCAR-T cells. The PD-1-disrupted EvCAR-T cells had an in vitro growth inhibitory effect on EGFRvIII-expressing GBM cells without altering the T-cell phenotype and the expression of other checkpoint receptors. In the future, the in vivo antitumor effect of this vector should be evaluated in order to determine if it could be applied clinically for improving the efficacy of EvCAR-T cell-based adoptive immunotherapy for GBM. for 30 min at 4 C, and the pellet was resuspended in the cold sterile medium or PBS (that was 1/20th to 1/10th the volume of the original solution) at 4 C and stored at ?80 C. 2.8. Induction of PD-1-Disrupted Primary Human EvCAR-T Cells PBMCs were prepared from heparinized peripheral blood obtained from a healthy volunteer using a conventional preparation kit (Lymphoprep; Axis-Shield PoC AS, Oslo, Norway). The PBMCs were transfected with 5 g of the CRISPR/Cas9 expression vectors or 2.5 g of the control pmaxGFP vector SPP1 by Nucleofector 2b (Lonza, K?ln, Germany), using the Amaxa Human T cell BC2059 Nucleofector Kit (VPA-1002; Lonza). Electroporation program V024 was used. After electroporation, the cells were resuspended in AIM-V medium (Thermo Fisher Scientific) containing 10% autoplasma, transferred into a 6-well plate (Corning), and incubated for 4 h at 37 C in a humidified atmosphere containing 5% CO2. The cells were washed and suspended in AIM-V medium supplemented with 200 IU/mL interleukin (IL)-2 (Novartis, Basel, Switzerland) and 10% autoplasma, transferred to 24-well plates (Corning) coated with 5 g/mL of purified anti-CD3 antibody (OKT-3; Miltenyi Biotec) and 2.5 g/mL of purified anti-CD28 antibody (15E8; Miltenyi Biotec), and cultured for 24 h under standard culture conditions. The transfection efficiency BC2059 was determined with a BD FACSCalibur flow cytometer or by manually counting the number of GFP-positive cells. Then, the EvCAR-carrying SIN lentivirus (MOI: 1) was added and centrifuged at 2600 rpm for 45 min at room temperature. After virus infection, the cells were cultured and expanded in AIM-V medium containing 200 IU/mL of IL-2 without autoplasma for 21 days. 2.9. Gene Disruption Efficacy of the CRISPR/Cas9 Expression Vectors Gene-disrupted cells were harvested, and their genomic DNA was extracted using the QIA amp DNA mini kit (Qiagen, Hilden, Germany). The T7 endonuclease-based assay was performed using the Guide-it Mutation Detection Kit (TAKARA Bio, Shiga, Japan) according to the manufacturers instructions. Briefly, the targeted regions of PD-1 were amplified from genomic DNA using KOD FX (TOYOBO, Osaka, Japan). The BC2059 PCR conditions were as follows: 1 cycle at 94 C for 2 min followed by 40 cycles at 98 C for 10 s, 63 C for 30 s, and 68 C for 30 s, and finally 1 cycle at 68 C for 7 min. PCR was performed using the BC2059 thermal cycler Life ECO (Bioer Technologies Co. Ltd., Hangzhou, China). The sequences of the primers used (from Thermo Fischer Scientific) were as follows: PD-1 exon 1: 5-AGCACTGCCTCTGTCACTCTCG-3 (forward) and 5-AAGCCACACAGCTCAGGGTAAG-3 (reverse), PD-1 exon 2: 5-GGACAACGCCACCTTCACCTGC-3 (forward) and 5-CTACGACCCTGGAGCTCCTGAT-3 (reverse). The amplification product of the PD-1 exon 1 primers and the PD-1 exon 2 primers were 471 base pairs (bp) and 476 bp in length, respectively. The PCR products were denatured and re-annealed in New England Biolabs (NEB) buffer by using the thermal cycler LifeECO under the following conditions: 95 C for 5 min, decrease in temperature by 2 C every second from 95 C to 85 C, decrease in temperature by 0.1 C per second from 85 C to 25 C, and decrease in temperature to 4 C. Rehybridized.