Challenges of CRISPR-based Gene Editing in Primary T Cells

Author(s):  
Alaleh Rezalotfi ◽  
Lea Fritz ◽  
Reinhold Förster ◽  
Berislav Bošnjak

Adaptive T cell immunotherapy holds great promise for the successful treatment of leukemia as well as other types of cancers. More recently, it was also shown to be an effective treatment option for chronic virus infections in immunosuppressed patients. Autologous or allogeneic T cells used for immunotherapy are usually genetically modified to express novel T cell or chimeric antigen receptors. The production of such cells was significantly simplified with the CRISPR/Cas system allowing deletion or insertion of novel genes at specific locations within the genome. In this review, we describe recent methodological breakthroughs important for the conduction of these genetic modifications, summarize crucial points to be considered when conducting such experiments, and highlight the potential pitfalls of these approaches.

2020 ◽  
Vol 17 (6) ◽  
pp. 600-612 ◽  
Author(s):  
Ling Wu ◽  
Qianru Wei ◽  
Joanna Brzostek ◽  
Nicholas R. J. Gascoigne

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2043-2043 ◽  
Author(s):  
Ulrike Mock* ◽  
Lauren Nickolay* ◽  
Gordon Weng-Kit Cheung ◽  
Hong Zhan ◽  
Karl Peggs ◽  
...  

Abstract BACKGROUND Genetically modified T cells have enormous potential for the treatment of relapsed and refractory haematopoietic malignancies. CD19-positive B-cell malignancies including acute lymphoblastic leukaemia (ALL), chronic lymphocytic leukaemia (CLL) or B cell non-Hodgkin lymphomas (NHL) have been shown to be an excellent target for adoptive immunotherapy with T cells expressing CD19-specific chimeric antigen receptors (CARs). The increasing need for genetically modified T cells is hampered by the limited number of centres with the required infrastructure and expertise to produce this complex therapeutic product. Ex vivo modification of T cells requires isolation, activation, transduction, expansion and cryopreservation steps. To simplify procedures and widen applicability for clinical therapies, Miltenyi Biotec has developed the CliniMACS Prodigy platform and is automating complex cell manufacturing processes. These have now been adapted for lentiviral transduction of T cells and we show the feasibility and effectiveness of the device for adoptive immunotherapy using chimeric antigen receptors. METHODS A self-inactivating third generation lentiviral vector encoding a CAR specific for CD19 (CAR19) was used for automated T-cell transductions (TCT). Using closed single-use tubing sets (TS520), fresh or cryopreserved peripheral blood mononuclear cells from non-mobilised leukapheresis collected from healthy donors were loaded onto the CliniMACS Prodigy, washed and activated in TexMACS media with TransAct, a polymeric nanomatrix activation reagent agonist for CD3 and CD28. Cells were transduced 24-48h after activation and expanded in the CentriCult-Unit of the tubing set, allowing for stable culture conditions as well as automated feeding and media exchange. Small and large scale comparison transductions were run in parallel to assess the efficiency of the automated T-cell modification. Finally, cells were harvested and cryopreserved to assess the functional capabilities of CAR19 T cells. RESULTS Three automated TCT runs were performed and continuously monitored to assess cell expansion, transduction efficiency and the phenotype of the final cell product. On average, expansion during automated cultivation was 11.7x (range: 5.4 - 22.8x) which was comparable to the expansion achieved in small scale controls (12.3x ± 1.2x). The average yield from the automated process was 11.8x108 total lymphocytes/run (ranging between 4 - 23.2x108 lymphocytes/run). Notably, this was comparable to existing CAR19 T cell manufacturing processes using a WAVE-Bioreactor. In all three runs in the Prodigy, successful transduction was observed with an average transduction efficiency of 32% CAR19-positive cells (range: 22- 45%). Again, this was similar to transduction efficiencies (32% CAR19-positive; range: 27-40%) in previous WAVE-production campaigns using X-Vivo15 media and magnetic beads conjugated with anti-CD3/CD28 antibodies for T-cell activation (Dynabeads). Flow cytometry analysis of the final cell product showed a high purity of CD45+/CD3+ cells (90%) as well as a relatively high frequency of CD8-positive cytotoxic T cells (56%). Immunophenotyping revealed high expression of CD45RA, CD62L, CD27 and CD95 with moderate expression of CCR7. Importantly, no significant difference in PD-1 expression was observed between automatically and manually processed cells. Finally, functional analysis showed cytotoxic activity as well as IFN-γ/TNF-α production upon co-cultivation with CD19-expressing target cells. CONCLUSION In summary, we have demonstrated the feasibility of the CliniMACS Prodigy for the generation of CAR+ T cells for adoptive immunotherapy. Automated activation, transduction and expansion resulted in clinically relevant doses of CAR19 T cells with very little 'hands-on' operator time. Given the closed-system nature of the device, and automated features, the CliniMACS Prodigy should widen applicability of T-cell engineering beyond centres with highly specialised infrastructures. Disclosures Mock*: Miltenyi Biotec GmbH: Research Funding. Nickolay*:Miltenyi Biotec GmbH: Research Funding. Peggs:Cellectis: Research Funding; Autolus: Consultancy, Equity Ownership. Johnston:Miltenyi Biotec GmbH: Employment. Kaiser:Miltenyi Biotec GmbH: Employment. Pule:CELLECTIS: Research Funding; AUTOLUS: Employment, Equity Ownership, Research Funding; AMGEN: Honoraria; UCLB: Patents & Royalties. Thrasher:Miltenyi Biotec GmbH: Research Funding; Autolus Ltd: Consultancy, Equity Ownership, Research Funding. Qasim:Cellectis: Research Funding; Miltenyi Biotec GmbH: Research Funding; Autolus Ltd: Consultancy, Equity Ownership, Research Funding; Cell Medica: Research Funding.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5949-5949
Author(s):  
Liora M. Schultz ◽  
Debra K Czerwinski ◽  
Aihua Fu ◽  
Shoshana Levy ◽  
Ronald Levy

Abstract The processes of ex vivo transduction of T cells to express chimeric antigen receptors (CARs) and of CAR+ T cell expansion influence the phenotype, function and ultimate fate of the final CAR+T cell product infused into patients. CAR constructs, despite expression of endogenous activation signals, require exogenous T cell activation during CAR transduction to allow optimal lenti-viral or retroviral-mediated integration of the CAR gene of interest into T cells. Clinical CAR therapy trials utilize anti-CD3 antibody-mediated activation or combined CD3 and CD28 stimulation using CD3, CD28 specific magnetic beads. We introduce novel magnetic nanoparticle beads generated from iron oxide nanoparticles conjugated to streptavidin and bound to biotinylated T cell activating antibodies for the purpose of CAR transduction. The small size of these nanobeads confers the advantage of decreased steric hindrance and enhanced capability of bead surface antibodies to access T cell surface antigen for binding and stimulation. We achieve efficient CAR transduction using anti-CD3 nanobead-mediated T cell stimulation and demonstrate CD19 specific CAR-mediated cytotoxicity of CD19+ tumor using an annexin V and 7AAD cytotoxicity assay. Evaluation of T cell phenotype following anti-CD3 nanobead-mediated T cell activation demonstrates preferential activation of naïve T cells as compared to central and effector memory cells. Addition of anti-CD28 costimulation is not necessary to achieving or inhibiting this preferential naïve T cell activation. Naïve T cells exhibit greater replicative capacity and anti-tumor function as compared to both effector and central memory T cells for adoptive transfer. We anticipate that preferential generation of naïve T cell derived CAR+ T cells achieved by introducing anti-CD3 nanobead stimulation can further improve the outcomes of clinical trials using CAR therapy. Disclosures Fu: NVIGEN Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.


Author(s):  
Mansour Poorebrahim ◽  
Niloufar Mohammadkhani ◽  
Reza Mahmoudi ◽  
Monireh Gholizadeh ◽  
Elham Fakhr ◽  
...  

AbstractNeoepitopes or neoantigens are a spectrum of unique mutations presented in a particular patient’s tumor. Neoepitope-based adoptive therapies have the potential of tumor eradication without undue damaging effect on normal tissues. In this context, methods based on the T cell receptor (TCR) engineering or chimeric antigen receptors (CARs) have shown great promise. This review focuses on the TCR-like CARs and TCR-CARs directed against tumor-derived epitopes, with a concerted view on neoepitopes. We also address the current limitations of the field to know how to harness the full benefits of this approach and thereby design a sustained and specific antitumor therapy.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A114-A114
Author(s):  
Amorette Barber

BackgroundAdoptive transfer of T cells is a promising anti-tumor therapy for many cancers. To enhance tumor recognition by T cells, chimeric antigen receptors (CAR) consisting of signaling domains fused to receptors that recognize tumor antigens can be expressed in T cells. One receptor that is a prospective target for a new chimeric antigen receptor is PD1 because the ligands for the PD1 receptor are expressed on many cancer types. Therefore, we developed a murine chimeric PD1 receptor (chPD1) consisting of the PD1 receptor extracellular domain and the activation domain of CD3 zeta. In addition, current chimeric antigen receptor therapies utilize various costimulatory domains to enhance anti-tumor efficacy. Therefore, we also compared the inclusion of CD28, Dap10, 4-1BB, GITR, ICOS, or OX40 costimulatory domains in the chPD1 receptor to determine which costimulatory domain induced optimal anti-tumor immunity.MethodsTo determine if this novel CAR could potentially target a wide variety of tumors, the anti-tumor efficacy of chPD1 T cells against murine lymphoma, melanoma, kidney, pancreatic, liver, colon, breast, ovarian, prostate, and bladder cancer cell lines was measured.ResultsOf the eighteen cell lines tested, all expressed PD1 ligands on their cell surface, making them potential targets for chPD1 T cells. Regardless of the costimulatory domain in the CAR, all of the chPD1 T cells induced similar levels of T cell proliferation and tumor cell lysis. However, differences were observed in the cytokine secretion profiles depending on which costimulatory receptor was included in the CAR. While most of the chPD1 T cell receptor combinations secreted both pro-inflammatory (IFNγ, TNFα, IL-2, GM-CSF, IL-17, and IL-21) and anti-inflammatory cytokines (IL-10), chPD1 T cells containing a Dap10 costimulatory domain secreted high levels of proinflammatory cytokines but did not secrete a significant amount of anti-inflammatory cytokines. Furthermore, T cells expressing chPD1 receptors with a Dap10 domain also had the strongest anti-tumor efficacy in vivo. ChPD1 T cells did not survive for longer than 14 days in vivo, however treatment with chPD1 T cells induced long-lived protective host-anti-tumor immune responses in tumor-bearing mice.ConclusionsTherefore, adoptive transfer of chPD1 T cells could be a novel therapeutic strategy to treat multiple types of cancer and inclusion of the Dap10 costimulatory domain in chimeric antigen receptors may induce a preferential cytokine profile for anti-tumor therapies.Ethics ApprovalThe study was approved by Longwood University’s IACUC.


2021 ◽  
Vol 12 ◽  
Author(s):  
Cody D. Moorman ◽  
Sue J. Sohn ◽  
Hyewon Phee

Autoimmune diseases affect roughly 5-10% of the total population, with women affected more than men. The standard treatment for autoimmune or autoinflammatory diseases had long been immunosuppressive agents until the advent of immunomodulatory biologic drugs, which aimed at blocking inflammatory mediators, including proinflammatory cytokines. At the frontier of these biologic drugs are TNF-α blockers. These therapies inhibit the proinflammatory action of TNF-α in common autoimmune diseases such as rheumatoid arthritis, psoriasis, ulcerative colitis, and Crohn’s disease. TNF-α blockade quickly became the “standard of care” for these autoimmune diseases due to their effectiveness in controlling disease and decreasing patient’s adverse risk profiles compared to broad-spectrum immunosuppressive agents. However, anti-TNF-α therapies have limitations, including known adverse safety risk, loss of therapeutic efficacy due to drug resistance, and lack of efficacy in numerous autoimmune diseases, including multiple sclerosis. The next wave of truly transformative therapeutics should aspire to provide a cure by selectively suppressing pathogenic autoantigen-specific immune responses while leaving the rest of the immune system intact to control infectious diseases and malignancies. In this review, we will focus on three main areas of active research in immune tolerance. First, tolerogenic vaccines aiming at robust, lasting autoantigen-specific immune tolerance. Second, T cell therapies using Tregs (either polyclonal, antigen-specific, or genetically engineered to express chimeric antigen receptors) to establish active dominant immune tolerance or T cells (engineered to express chimeric antigen receptors) to delete pathogenic immune cells. Third, IL-2 therapies aiming at expanding immunosuppressive regulatory T cells in vivo.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2902-2902 ◽  
Author(s):  
Omkar Uday Kawalekar ◽  
Avery D. Posey ◽  
Joseph Fraietta ◽  
Jihyun Lee ◽  
John Scholler ◽  
...  

Abstract Background Chimeric Antigen Receptors (CARs) have shown great promise in the field of targeted adoptive immunotherapy against cancer. These receptors are specific for tumor antigens and have the binding properties of monoclonal antibodies with signaling molecules of T cells. When expressed on T cells, these receptors help the cells home to tumor targets and perform their cytotoxic functions. CARs containing the 4-1BB signaling domain have been used against B-cell chronic lymphocytic leukemia and have shown the most clinical success in terms of tumor targeting and persistence in patients upon engraftment. In contrast, their CD28-containing CAR counterpart failed to show comparable persistence in patients. Despite extensive clinical use, the detailed molecular mechanisms involved in the activation of CAR-grafted T cells remain elusive. To address this, we hypothesize that CARs take advantage of the endogenous T cell receptor (TCR) signaling pathways in a manner unique to their analogous intracellular domains. Methods By electroporation of CAR encoding in vitro transcribed RNA into primary human T cells, we achieved >90% CAR-positive T cell population. We expressed different CARs constructs, all specific for a widely expressed tumor antigen - mesothelin. Keeping the scFv region constant to SS1 that is specific for mesothelin, we varied the intracellular signaling domains (ICDs) ranging from first generation CARs (containing only the CD3z ICD) to the second generation CARs (CD28-CD3z or 41BB-CD3z ICDs) Upon verifying CAR expression by flow cytometry, these T cells were stimulated with mesothelin antigen to analyze differences in signaling between the different CAR groups. Results Here we report that CARs with CD28 show stronger activation of T cells when compared to CARs with 4-1BB or CD3z alone. Stimulation of different CAR constructs revealed that the antigen-specific activation threshold for CAR-T cells is greatly reduced when the CD28 endodomain is included in the CAR architecture. This activation state, measured by the activation of proximal signaling proteins, as well as the MAPK and Akt signaling pathways continues to increase and persist for longer time durations in T cells with the CD28-containing CAR construct. Co-immunoprecipitation studies reveal direct interaction of CARs with pZAP70 and TRAF proteins, but not other known signaling molecules of the TCR complex. T cells with CARs containing CD28 intracellular domain showed a high and sustained level of calcium flux in comparison to T cells with the 4-1BB containing CARs. Experiments to determine the molecular signatures of CAR-grafted T cells stimulated with cognate antigen for longer time durations are currently underway. Taken together, these studies have significant impact on the future design of CARs and adoptive immunotherapy. Disclosures: Kawalekar: Novartis: Research Funding. Posey:Novartis: Research Funding. Fraietta:Novartis: Research Funding. Lee:Novartis: Research Funding. Zhao:Novartis: Research Funding. June:Novartis: Research Funding.


2018 ◽  
Vol 2 (5) ◽  
pp. 517-528 ◽  
Author(s):  
Takahiro Kamiya ◽  
Desmond Wong ◽  
Yi Tian Png ◽  
Dario Campana

Key Points Newly designed PEBLs prevent surface expression of T-cell receptor in T cells without affecting their function. Combined with chimeric antigen receptors, PEBLs can rapidly generate powerful antileukemic T cells without alloreactivity.


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