Journal Articles

Dendritic cell centric nanoengineering couples antigen acquisition and STING activation for cancer immunotherapy Spotlight 

Xiang et al. developed a DC-directed dual pH-gated hybrid nanoparticle (HNP) that sequentially releases αCD47 peptides in the acidic TIME to enhance antigen acquisition and subsequently cGAMP under endosomal acidification to activate intracellular STING. HNP enhanced cDC1 cross-presentation and CD8+ T cell priming, forming CXCL9-enriched cDC1 niches with increased local CD8+ T cell accumulation. HNP suppressed MC38 tumor growth and orthotopic 4T1 metastasis through Batf3-dependent cDC1s and CD8+ T cells, but not macrophages. It also enhanced human DC T cell priming and antitumor activity in a CD34+ humanized xenograft model.

Contributed by Shishir Pant

Xiang et al. developed a DC-directed dual pH-gated hybrid nanoparticle (HNP) that sequentially releases αCD47 peptides in the acidic TIME to enhance antigen acquisition and subsequently cGAMP under endosomal acidification to activate intracellular STING. HNP enhanced cDC1 cross-presentation and CD8+ T cell priming, forming CXCL9-enriched cDC1 niches with increased local CD8+ T cell accumulation. HNP suppressed MC38 tumor growth and orthotopic 4T1 metastasis through Batf3-dependent cDC1s and CD8+ T cells, but not macrophages. It also enhanced human DC T cell priming and antitumor activity in a CD34+ humanized xenograft model.

Contributed by Shishir Pant

ABSTRACT: Stimulator of interferon genes (STING) agonists have shown limited antitumor efficacy, in part because STING activation is not preferentially focused on dendritic cells (DCs), which specialize in cross-priming. We present a DC-centric strategy that synergistically licenses DCs by coordinating CD47-SIRP_ checkpoint relief and STING activation via dual ultra-pH-sensitive gating. Mild tumor acidity first unmasks the _CD47 cue to prime antigen acquisition. Following DC-biased uptake, a second acidic gate releases cGAMP to engage STING in antigen-bearing DCs. Functionally, efficacy requires Batf3-dependent cDC1s and CD8(+) T cells, yet is preserved after macrophage depletion. In murine models, this strategy suppresses tumor growth and metastasis with good tolerability, and it retains activity in a humanized cell-line-derived xenograft model established in NSG-SGM3 hosts, supporting activity in a partially reconstituted human immune setting. Together, this work presents a mechanism-guided combination strategy to optimize STING agonist therapy.

Author Info: (1) Department of Pharmaceutics, Jiang Su Key Laboratory of Drug Design and Optimization, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009

Author Info: (1) Department of Pharmaceutics, Jiang Su Key Laboratory of Drug Design and Optimization, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China. (2) School of Medicine, Nankai University, Tianjin 300071, China; Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, State Key Laboratory of Druggability Evaluation and Systematic Translational Medicine, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China. (3) Department of Pharmaceutics, Jiang Su Key Laboratory of Drug Design and Optimization, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China. (4) Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, State Key Laboratory of Druggability Evaluation and Systematic Translational Medicine, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China. (5) Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, State Key Laboratory of Druggability Evaluation and Systematic Translational Medicine, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China. (6) Tianjin Central Hospital of Obstetrics and Gynecology/Nankai University Affiliated Maternity Hospital, Tianjin Key Laboratory of Human Development and Reproductive Regulation, Tianjin 300100, China. (7) Department of Pharmaceutics, Jiang Su Key Laboratory of Drug Design and Optimization, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China. (8) Department of Pharmaceutics, Jiang Su Key Laboratory of Drug Design and Optimization, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China. (9) State Key Laboratory of Druggability Evaluation and Systematic Translational Medicine, Tianjin Institute of Pharmaceutical Research, 306 Huiren Road, Tianjin 300301, P.R. China. (10) Department of Pharmaceutics, Jiang Su Key Laboratory of Drug Design and Optimization, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China. (11) Department of Pharmaceutics, Jiang Su Key Laboratory of Drug Design and Optimization, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China. (12) School of Medicine, Nankai University, Tianjin 300071, China; Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, State Key Laboratory of Druggability Evaluation and Systematic Translational Medicine, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China. Electronic address: renxiubao@tjmuch.com. (13) Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, State Key Laboratory of Druggability Evaluation and Systematic Translational Medicine, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China. Electronic address: wsong@tmu.edu.cn. (14) Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, State Key Laboratory of Druggability Evaluation and Systematic Translational Medicine, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China. Electronic address: qintingting@tjmuch.com. (15) Department of Pharmaceutics, Jiang Su Key Laboratory of Drug Design and Optimization, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China. Electronic address: suxin.li@cpu.edu.cn. (16) Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, State Key Laboratory of Druggability Evaluation and Systematic Translational Medicine, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China; Haihe Laboratory of Cell Ecosystem, Tianjin 300100, China. Electronic address: jianwang03@tmu.edu.cn.

Breast cancer prevention by prophylactic Lalba mRNA-LNP vaccination Spotlight 

Nishida et al. sought to prevent carcinogen (NMU)-induced mammary tumorigenesis in outbred Sprague-Dawley rats by targeting LALBA, a protein specifically expressed in luminal progenitor (LP) cells – the proposed cell-of-origin for breast cancer. Vaccination with N1-methylpseudouridine-modified Lalba mRNA-LNP induced antigen-specific immune responses, suppressed tumor incidence or progression, and extended tumor-free and overall survival. scRNAseq revealed a reduced frequency of proliferative LP cells upon vaccination, suggesting effective targeting of immunoreactive early mammary epithelial lesions.

Contributed by Ute Burkhardt

Nishida et al. sought to prevent carcinogen (NMU)-induced mammary tumorigenesis in outbred Sprague-Dawley rats by targeting LALBA, a protein specifically expressed in luminal progenitor (LP) cells – the proposed cell-of-origin for breast cancer. Vaccination with N1-methylpseudouridine-modified Lalba mRNA-LNP induced antigen-specific immune responses, suppressed tumor incidence or progression, and extended tumor-free and overall survival. scRNAseq revealed a reduced frequency of proliferative LP cells upon vaccination, suggesting effective targeting of immunoreactive early mammary epithelial lesions.

Contributed by Ute Burkhardt

ABSTRACT: Tumor-suppressive immunity is more evident in early-stage compared to advanced tumors making it the ideal point for cancer interceptive immunotherapies. We previously described that higher peripheral T cell diversity is associated with more pronounced CD8(+) T cell infiltration in ductal carcinoma in situ of the breast, implying a close interaction between peripheral and intratumor immunity. Here, we developed lipid nanoparticle (LNP)-encapsulated messenger ribonucleic acid (mRNA) vaccines expressing the alpha-lactalbumin (LALBA) protein unique to mammary luminal progenitors (LPs) to test whether enhancing immune response by prophylactic vaccination against the putative cell-of-origin of breast cancer suppresses tumorigenesis. Vaccination of outbred Sprague-Dawley rats with N1-methylpseudouridine-modified or unmodified Lalba mRNA-LNP induced different degrees of LALBA-specific and nonspecific immune responses. The vaccination suppressed carcinogen-induced mammary tumorigenesis and improved tumor-free and overall survival without obvious toxicity in the normal mammary glands and other organs. Single-cell transcriptomic analysis revealed that vaccination decreases the frequency of a proliferative LP population in immunoreactive early epithelial hyperplasia. Overall, we provide proof of principle that prophylactic Lalba mRNA-LNP has the potential to suppress the initiation and progression of early breast neoplastic lesions.

Author Info: (1) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215. ROR: https://ror.org/02jzgtq86 Department of Medicine, Harvard Medical School, Boston, MA 02115.

Author Info: (1) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215. ROR: https://ror.org/02jzgtq86 Department of Medicine, Harvard Medical School, Boston, MA 02115. Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115. ROR: https://ror.org/04b6nzv94 (2) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215. ROR: https://ror.org/02jzgtq86 Department of Medicine, Harvard Medical School, Boston, MA 02115. Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115. ROR: https://ror.org/04b6nzv94 (3) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215. ROR: https://ror.org/02jzgtq86 Department of Medicine, Harvard Medical School, Boston, MA 02115. Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115. ROR: https://ror.org/04b6nzv94 (4) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215. ROR: https://ror.org/02jzgtq86 Department of Medicine, Harvard Medical School, Boston, MA 02115. Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115. ROR: https://ror.org/04b6nzv94 (5) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215. ROR: https://ror.org/02jzgtq86 Department of Medicine, Harvard Medical School, Boston, MA 02115. Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115. ROR: https://ror.org/04b6nzv94 (6) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215. ROR: https://ror.org/02jzgtq86 Department of Medicine, Harvard Medical School, Boston, MA 02115. Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115. ROR: https://ror.org/04b6nzv94 (7) Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104. ROR: https://ror.org/00b30xv10 (8) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215. ROR: https://ror.org/02jzgtq86 Department of Medicine, Harvard Medical School, Boston, MA 02115. Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115. ROR: https://ror.org/04b6nzv94 (9) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215. ROR: https://ror.org/02jzgtq86 Department of Medicine, Harvard Medical School, Boston, MA 02115. Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115. ROR: https://ror.org/04b6nzv94 (10) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215. ROR: https://ror.org/02jzgtq86 Department of Medicine, Harvard Medical School, Boston, MA 02115. Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115. ROR: https://ror.org/04b6nzv94 (11) Acuitas Therapeutics, Vancouver, BC, Canada V6T 1Z3. (12) Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104. ROR: https://ror.org/00b30xv10 (13) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215. ROR: https://ror.org/02jzgtq86 Department of Medicine, Harvard Medical School, Boston, MA 02115. Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115. ROR: https://ror.org/04b6nzv94

Immune checkpoint blockade facilitates primary tumor rejection in a cDC1-independent manner without immunological memory acquisition

Spotlight 

Arisato et al. found that the LLC-2B2 subclone of LLC was universally rejected in ICB-treated WT mice and was also rejected in 36% of ICB-treated Batf3-/- mice. In Batf3-/- mice, rejection was dependent on CD8+ T cells primed by alternative XCR1- APCs, which upregulated costimulatory CD80, CD86, and CD40 in response to soluble factors secreted by LLC-2B2 cells. However, when mice that had cleared LLC-2B2 tumors were rechallenged, all WT mice rejected tumors, while most Batf3-/- mice did not, suggesting that cDC1s were important in establishing protective immune memory. Intratumoral injection of Flt3L-DCs restored protection from rechallenge.

Contributed by Lauren Hitchings

Arisato et al. found that the LLC-2B2 subclone of LLC was universally rejected in ICB-treated WT mice and was also rejected in 36% of ICB-treated Batf3-/- mice. In Batf3-/- mice, rejection was dependent on CD8+ T cells primed by alternative XCR1- APCs, which upregulated costimulatory CD80, CD86, and CD40 in response to soluble factors secreted by LLC-2B2 cells. However, when mice that had cleared LLC-2B2 tumors were rechallenged, all WT mice rejected tumors, while most Batf3-/- mice did not, suggesting that cDC1s were important in establishing protective immune memory. Intratumoral injection of Flt3L-DCs restored protection from rechallenge.

Contributed by Lauren Hitchings

ABSTRACT: Immune checkpoint blockade (ICB) provides durable therapeutic responses across multiple cancer types. Although crosstalk between T cells and conventional type 1 dendritic cells (cDC1s) is essential, the contribution of other antigen-presenting cells (APCs) to ICB-induced tumor rejection remains unclear. To address this, we show that while the majority of wild type (WT) mice rejected an immunogenic clone of Lewis lung carcinoma (LLC) following ICB, 35.7% of Batf3–/– mice, which lack the cDC1 subset, also rejected this LLC clone. ICB induced the upregulation of costimulatory markers on XCR1– APCs in the tumors and lymph nodes of Batf3–/– mice, similar to responses observed in wild-type mice. Mechanistically, conditioned culture media from LLC, but not from ICB-resistant B16F10 melanoma cells, stimulated bone marrow-derived cDC1s and cDC2s, as evidenced by the upregulation of CD40 and CD80 expression. RNA sequencing revealed that antitumor immunity-related genes were upregulated in LLC cells compared with B16F10 cells. To determine the role of cDC1-independent long-term immune memory, we rechallenged ICB-induced tumor-free mice with LLC tumors. We found that, without supplementation of cDC1s during primary rejection, Batf3–/– mice failed to spontaneously reject the rechallenged tumors. These findings demonstrate that ICB can elicit primary antitumor T cell responses against immunogenic tumors in the absence of cDC1s, whereas cDC1s are essential for the establishment of ICB-induced long-term memory. Our study underscores the importance of clinical strategies targeting both cDC1-dependent and cDC1-independent pathways to enhance the durable efficacy of ICB.

Author Info: 1. Department of Medical Oncology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan 2. Department of Respiratory Medicine, Faculty of Medici

Author Info: 1. Department of Medical Oncology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan 2. Department of Respiratory Medicine, Faculty of Medicine, Hokkaido University, Sapporo, Japan 3. Department of Medical Oncology, Shinshu Cancer Center, Shinshu University Hospital, Matsumoto, Japan 4. Division of Molecular Psychoimmunology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan 5. Department of Medical Oncology, Hokkaido University Hospital, Sapporo, Japan 6. Division of Clinical Cancer Genomics, Hokkaido University Hospital, Sapporo, Japan 7. Quantum immunology Team, Institute for Quantum Life science, National Institute for Quantum and Radiological Science and Technology (QST), Chiba, Japan 8. Division of Molecular Neuroimmunology, Department of Homeostatic Regulation, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Aichi, Japan 9. Institute for Vaccine Research and Development, Hokkaido University, Sapporo 001-0021, Japan

Enfortumab vedotin induces immunogenic cell death and shows enhanced preclinical antitumor activity when combined with a PD-1 inhibitor Featured  

Untangling the mechanism of enfortumab vedotin – an antibody–drug conjugate that targets Nectin-4 on cancer cells – Olson and Liu et al. showed that upon target binding, the drug is imported into the cell and transported to the lysosome, where MMAE is released, inducing direct cytotoxicity by disrupting microtubule formation and inducing ER stress and immunogenic cell death (ICD). Upon ICD, MMAE is released from the cell, killing nearby bystander cells. ICD also induces macrophage and DC activation, initiating protective antitumor immunity against both Nectin-4+ and Nectin-4- tumor cells. Enfortuman vedotin also synergized with anti-PD-1.

Untangling the mechanism of enfortumab vedotin – an antibody–drug conjugate that targets Nectin-4 on cancer cells – Olson and Liu et al. showed that upon target binding, the drug is imported into the cell and transported to the lysosome, where MMAE is released, inducing direct cytotoxicity by disrupting microtubule formation and inducing ER stress and immunogenic cell death (ICD). Upon ICD, MMAE is released from the cell, killing nearby bystander cells. ICD also induces macrophage and DC activation, initiating protective antitumor immunity against both Nectin-4+ and Nectin-4- tumor cells. Enfortuman vedotin also synergized with anti-PD-1.

ABSTRACT: Enfortumab vedotin is a Nectin-4-directed antibody-drug conjugate designed to deliver the microtubule-disrupting agent monomethyl auristatin E (MMAE) to tumor cells. Using preclinical models of urothelial cancer (UC), we expand the understanding of the multifaceted mechanism of action for enfortumab vedotin that includes direct cytotoxicity on Nectin-4-positive tumor cells, indirect bystander effect on neighboring Nectin-4-negative tumor cells, and MMAE-mediated induction of immunogenic cell death (ICD) and associated increase in activated immune cells in the tumor microenvironment. Importantly, vaccination with enfortumab vedotin-treated tumor cells results in protection against tumor rechallenge in mice, consistent with antitumor immunity. MMAE-mediated ICD induction modulates the tumor microenvironment in a complementary manner to immune checkpoint inhibition. Accordingly, enfortumab vedotin plus PD-1 inhibitor shows enhanced antitumor activity in vivo. These preclinical findings provide mechanistic hypotheses that may be relevant to the improved clinical outcomes observed for enfortumab vedotin plus pembrolizumab relative to chemotherapy.

Author Info: (1) Pfizer, Inc., Bothell, WA 98021, USA. (2) Pfizer, Inc., Bothell, WA 98021, USA. (3) Seagen, Inc., Bothell, WA 98021, USA. (4) Pfizer, Inc., Bothell, WA 98021, USA. (5) Pfizer,

Author Info: (1) Pfizer, Inc., Bothell, WA 98021, USA. (2) Pfizer, Inc., Bothell, WA 98021, USA. (3) Seagen, Inc., Bothell, WA 98021, USA. (4) Pfizer, Inc., Bothell, WA 98021, USA. (5) Pfizer, Inc., Bothell, WA 98021, USA. (6) Pfizer, Inc., Bothell, WA 98021, USA. (7) Pfizer, Inc., Bothell, WA 98021, USA. (8) Seagen, Inc., Bothell, WA 98021, USA. (9) Pfizer, Inc., Bothell, WA 98021, USA. (10) Pfizer, Inc., Bothell, WA 98021, USA. (11) Pfizer, Inc., Bothell, WA 98021, USA. (12) Seagen, Inc., Bothell, WA 98021, USA. (13) Seagen, Inc., Bothell, WA 98021, USA. (14) Pfizer, Inc., Bothell, WA 98021, USA. (15) Pfizer, Inc., Bothell, WA 98021, USA. (16) Seagen, Inc., Bothell, WA 98021, USA. (17) Seagen, Inc., Bothell, WA 98021, USA. (18) Astellas Pharma Inc., Tsukuba, Ibaraki, Japan. (19) Astellas Research Institute of America LLC, Northbrook, IL 60062, USA. (20) Pfizer, Inc., Bothell, WA 98021, USA. (21) Pfizer, Inc., Bothell, WA 98021, USA. (22) Pfizer, Inc., Bothell, WA 98021, USA. Electronic address: sharsti.sandall@pfizer.com.

In vivo genome-wide CRISPR screens of human T cells in solid tumours Spotlight 

Liu et al. developed a genome-wide in vivo CRISPR screening platform using a T cell-attracting anti-CD3 scFv-expressing A375 tumor model and primary human T cells to identify in vivo regulators of intratumoral T cell abundance and effector function. The abundance screen identified P2RY8-Gα13 as a negative regulator of T cell tumor infiltration, whereas the IFNγ-based functional screen identified GNAS as a key driver of intratumoral T cell dysfunction. GNAS deletion enhanced CAR- and TCR-T cell fitness and efficacy across solid tumor models. P2RY8 and GNAS dual-knockout CAR T cells showed increased infiltration and improved tumor control.

Contributed by Shishir Pant

Liu et al. developed a genome-wide in vivo CRISPR screening platform using a T cell-attracting anti-CD3 scFv-expressing A375 tumor model and primary human T cells to identify in vivo regulators of intratumoral T cell abundance and effector function. The abundance screen identified P2RY8-Gα13 as a negative regulator of T cell tumor infiltration, whereas the IFNγ-based functional screen identified GNAS as a key driver of intratumoral T cell dysfunction. GNAS deletion enhanced CAR- and TCR-T cell fitness and efficacy across solid tumor models. P2RY8 and GNAS dual-knockout CAR T cells showed increased infiltration and improved tumor control.

Contributed by Shishir Pant

ABSTRACT: Large-scale CRISPR screening in human T cells holds significant promise for identifying genetic modifications that enhance cellular immunotherapy. Yet, many regulators of T cell performance in solid tumours are not revealed in vitro(1,2). In vivo screening in tumour-bearing mice is more physiological but has been limited by low intratumoural T cell recovery. Here we developed an in vivo model that efficiently recovers human T cells from solid tumours, permitting genome-wide CRISPR screens with few mice. Tumour-infiltrating T cells from this model exhibit hallmarks of dysfunction compared with splenic T cells, creating an ideal screening context. We performed two genome-wide CRISPR knockout screens to identify regulators of intratumoural T cell abundance and effector function. The abundance screen revealed the P2RY8-G_13 GPCR signalling axis as a negative regulator of T cell tumour infiltration. The effector function screen identified GNAS as a key driver of T cell dysfunction in tumours, whose product, G_s, acts as a convergent node downstream of multiple GPCRs sensing distinct suppressive ligands. Knockout of GNAS rendered T cells resistant to multiple suppressive cues and significantly improved efficacy across diverse solid tumour models in chimeric antigen receptor (CAR) and T cell receptor (TCR) systems. Combinatorial knockout of P2RY8-GNAS further enhanced tumour control, demonstrating that complementary in vivo screens can identify orthogonal targets whose combined editing improves therapeutic potency. This flexible, scalable platform can be adapted for systematic discovery of genetic strategies to improve solid tumour T cell therapies.

Author Info: (1) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. qi.liu3@ucsf.edu. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA

Author Info: (1) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. qi.liu3@ucsf.edu. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. qi.liu3@ucsf.edu. (2) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (3) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (4) Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (5) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (6) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (7) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (8) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. UCSF CoLabs, University of California San Francisco, San Francisco, CA, USA. Department of Surgery, University of California San Francisco, San Francisco, CA, USA. Diabetes Center, University of California San Francisco, San Francisco, CA, USA. (9) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (10) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (11) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (12) Department of Microbiology and Immunology and Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA, USA. (13) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (14) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (15) Department of Microbiology and Immunology and Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA, USA. Division of Pediatric Rheumatology, Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA. (16) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. (17) Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (18) Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA. (19) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (20) Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA. (21) Division of Oncology, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA. (22) Division of Immunology and Rheumatology, Department of Medicine, Stanford University, Stanford, CA, USA. Division of Computational Medicine, Department of Medicine, Stanford University, Stanford, CA, USA. (23) Division of Immunology and Rheumatology, Department of Medicine, Stanford University, Stanford, CA, USA. Division of Computational Medicine, Department of Medicine, Stanford University, Stanford, CA, USA. Parker Institute for Cancer Immunotherapy, San Francisco, CA, USA. Weill Cancer Hub West, Stanford University and University of California, San Francisco, CA, USA. (24) Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. Weill Cancer Hub West, Stanford University and University of California, San Francisco, CA, USA. Department of Laboratory Medicine, University of California San Francisco, San Francisco, CA, USA. UCSF Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA, USA. (25) Gray Faculty of Medical and Health Sciences, Tel Aviv University, Tel Aviv, Israel. George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel. Dotan Center for Advanced Therapies, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel. (26) Weill Cancer Hub West, Stanford University and University of California, San Francisco, CA, USA. Department of Pathology, University of California San Francisco, San Francisco, CA, USA. (27) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Parker Institute for Cancer Immunotherapy, San Francisco, CA, USA. Weill Cancer Hub West, Stanford University and University of California, San Francisco, CA, USA. UCSF Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA, USA. (28) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. Parker Institute for Cancer Immunotherapy, San Francisco, CA, USA. Weill Cancer Hub West, Stanford University and University of California, San Francisco, CA, USA. (29) Department of OB/Gyn, Center for Reproductive Sciences, University of California San Francisco, San Francisco, CA, USA. (30) Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. (31) Department of Microbiology and Immunology and Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA, USA. (32) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. Parker Institute for Cancer Immunotherapy, San Francisco, CA, USA. Weill Cancer Hub West, Stanford University and University of California, San Francisco, CA, USA. UCSF Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA, USA. Institute for Human Genetics (IHG), University of California San Francisco, San Francisco, CA, USA. Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA, USA. Innovative Genomics Institute, University of California Berkeley, Berkeley, CA, USA. (33) Department of Medicine, University of California San Francisco, San Francisco, CA, USA. julia.carnevale@ucsf.edu. Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA. julia.carnevale@ucsf.edu. Parker Institute for Cancer Immunotherapy, San Francisco, CA, USA. julia.carnevale@ucsf.edu. Weill Cancer Hub West, Stanford University and University of California, San Francisco, CA, USA. julia.carnevale@ucsf.edu. UCSF Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA, USA. julia.carnevale@ucsf.edu.

Engineered human iPSC-derived dendritic cells dressed with tumor MHC complexes as a cancer vaccine Spotlight 

Xu et al. identified optimal and reproducible culture and cytokine conditions to create universal, human iPSC-derived DCs lacking HLA (B2m/CTIIA KO) and with a CCR7+ migratory DC phenotype. An exosome-inspired process with tumor cell vesicles was used to cross-dress these DCs with peptide:MHC complexes from tumor cells. Cross-dressing promoted antigen presentation and resistance to “non-self” killing by NK cells. With cell lines in vitro and in vivo, the cross-dressed DCs enhanced T cell cytotoxicity and tumor control. Personal cross-dressed vaccines in AML and ovarian cancer were cytolytic in vitro. PD-L1/2 knockout improved activity.

Contributed by Ed Fritsch

Xu et al. identified optimal and reproducible culture and cytokine conditions to create universal, human iPSC-derived DCs lacking HLA (B2m/CTIIA KO) and with a CCR7+ migratory DC phenotype. An exosome-inspired process with tumor cell vesicles was used to cross-dress these DCs with peptide:MHC complexes from tumor cells. Cross-dressing promoted antigen presentation and resistance to “non-self” killing by NK cells. With cell lines in vitro and in vivo, the cross-dressed DCs enhanced T cell cytotoxicity and tumor control. Personal cross-dressed vaccines in AML and ovarian cancer were cytolytic in vitro. PD-L1/2 knockout improved activity.

Contributed by Ed Fritsch

ABSTRACT: Autologous-derived dendritic cells (DCs) are a promising source for cell-based cancer vaccines. However, their therapeutic potential is challenged by the number and quality produced and the diversity of antigens presented. To address these limitations, we present an approach that involves differentiating universal MHC-deficient human-induced pluripotent stem cells (hiPSCs) into CCR7(+) migratory DCs. These DCs are subsequently "dressed" with the full repertoire of MHC-antigen complexes derived from tumor cell membranes, transforming an allogeneic substrate into a personalized cancer vaccine product. The resulting "TumorDressed" DCs effectively activate T cells against tumor antigens. Their function is diminished when CD80/86 is deleted but significantly enhanced by the loss of PD-L1/2. PD-L1/2-null TumorDressed DCs demonstrate robust priming of anti-tumor T cell-mediated cytotoxicity both in vitro and in vivo, including against primary hematologic and solid tumors with matching patient T cells. These findings provide proof of concept for a universal, scalable, adaptable, and off-the-shelf DC cancer vaccine platform.

Author Info: (1) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, Univ

Author Info: (1) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, University of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. (2) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, University of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. (3) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, University of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. (4) Division of Hematology and Oncology, Department of Medicine, University of California, San Francisco (UCSF), San Francisco, CA, USA. (5) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, University of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. (6) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, University of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. (7) Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan. (8) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, University of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. (9) AIVITA Biomedical, Irvine, CA, USA. (10) Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan. (11) Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA; Division of Hematology and Oncology, Department of Medicine, University of California, San Francisco (UCSF), San Francisco, CA, USA. (12) AIVITA Biomedical, Irvine, CA, USA. (13) AIVITA Biomedical, Irvine, CA, USA. (14) Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA; Division of Hematology and Oncology, Department of Medicine, University of California, San Francisco (UCSF), San Francisco, CA, USA. (15) Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan. (16) Division of Hematology and Oncology, Department of Medicine, University of California, San Francisco (UCSF), San Francisco, CA, USA. (17) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, University of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. Electronic address: robert.blelloch@ucsf.edu.

Cancer Immunotherapy Using AIRE Conditioning of the Tumor Epitopeome Featured  

Chen, Pulido, et al. investigated how AIRE expression in tumor cells impacts antitumor immune responses using murine models. Overexpression of AIRE led to higher expression of self-proteins, MHC-I in the context of H-2Kb, and MHC-I-presented epitopes, whereas downregulation led to lower expression. Antitumor immunity could be induced by DC vaccines loaded with cell lysates of AIRE-overexpressing tumor cells, inducing CD8+ and CD4+ T cell responses. Therapeutic AIRE tumor expression could be induced with in vivo delivery of an AAV vector, which was effective in curing mice, and survival time was improved by subsequent ICB.

Chen, Pulido, et al. investigated how AIRE expression in tumor cells impacts antitumor immune responses using murine models. Overexpression of AIRE led to higher expression of self-proteins, MHC-I in the context of H-2Kb, and MHC-I-presented epitopes, whereas downregulation led to lower expression. Antitumor immunity could be induced by DC vaccines loaded with cell lysates of AIRE-overexpressing tumor cells, inducing CD8+ and CD4+ T cell responses. Therapeutic AIRE tumor expression could be induced with in vivo delivery of an AAV vector, which was effective in curing mice, and survival time was improved by subsequent ICB.

ABSTRACT: T-cell immune tolerance is established in part through the activity of the Auto-immune Regulator (AIRE) transcription factor in the medullary thymic epithelial cells (mTEC) of the thymus. AIRE induces expression of peripheral tissue-specific self-antigens for presentation to nave T cells to promote activation/deletion of autoreactive T cells. This traditional role of AIRE in mTECs is to prevent autoimmunity. Herein, we demonstrate that tumors mimic the role of AIRE in mTECs to evade immune rejection. We found that AIRE induced a profile of "selfness" at the RNA and protein levels which, when presented on major histocompatibility complexes, shielded the tumor from inherently self-tolerized T cells. Moreover, we describe an in vivo immunotherapy in which engineered changes in AIRE expression in tumor cells altered their profile of selfness, exposing both AIRE-modified and parental unmodified tumor cells to T-cell attack. Therefore, by re-setting the immunological selfness of cancer cells, this AIRE-mediated immunotherapy 1) converted a highly tolerized T-cell compartment into a tumor-reactive T-cell population; 2) conferred upon non-immunogenic tumors de novo sensitivity to immune checkpoint blockade; 3) removed the need to identify potentially immunogenic tumor-associated antigens as targets for generation of T-cell responses; and 4) lead to potent T cell-mediated rejection of aggressive, immunologically cold, non-immunogenic tumors. Patient RNA-sequencing data showed that expression of AIRE predicted response to immune therapies with a strong correlation between AIRE expression and markers of T-cell receptor signaling, suggesting our studies have therapeutic translational value.

Author Info: (1) Mayo Clinic Rochester, MN United States. ROR: https://ror.org/02qp3tb03 (2) Wills Eye Hospital Philadelphia, PA United States. ROR: https://ror.org/03qygnx22 (3) Mayo Clinic Ro

Author Info: (1) Mayo Clinic Rochester, MN United States. ROR: https://ror.org/02qp3tb03 (2) Wills Eye Hospital Philadelphia, PA United States. ROR: https://ror.org/03qygnx22 (3) Mayo Clinic Rochester, Minnesota United States. ROR: https://ror.org/02qp3tb03 (4) Mayo Clinic Rochester, MN United States. ROR: https://ror.org/02qp3tb03 (5) Mayo Clinic Rochester, MN United States. ROR: https://ror.org/02qp3tb03 (6) Mayo Clinic Rochester, MN United States. ROR: https://ror.org/02qp3tb03 (7) Mayo Clinic Rochester, MN United States. ROR: https://ror.org/02qp3tb03 (8) Vyriad United States. (9) Mayo Clinic Rochester, MN United States. ROR: https://ror.org/02qp3tb03 (10) Johns Hopkins Medicine Baltimore United States. ROR: https://ror.org/037zgn354 (11) Mayo Clinic Rochester, Minnesota United States. ROR: https://ror.org/02qp3tb03 (12) Mayo Clinic Rochester, MN United States. ROR: https://ror.org/02qp3tb03 (13) King's College London London United Kingdom. ROR: https://ror.org/0220mzb33 (14) Institute of Cancer Research London United Kingdom. ROR: https://ror.org/043jzw605 (15) Institute of Cancer Research London United Kingdom. ROR: https://ror.org/043jzw605 (16) Mayo Clinic Rochester, Minnesota United States. ROR: https://ror.org/02qp3tb03 (17) Mayo Clinic Rochester, MN United States. ROR: https://ror.org/02qp3tb03

Synthetic transcription factors designed by domain recombination enhance CAR T cell antitumor function Spotlight 

Takacsi-Nagy et al. generated a library of synthetic T cell Transcription Factors (sTFs) through combinatorial assembly of AP-1 family TF subdomains. Expressed in CAR-T cells, certain sTFs improved CAR-T persistence/proliferation over natural TFs in a chronic stimulation assay. sTFs induced unique transcriptional and epigenetic T cell states from natural TFs, although their DNA binding sites were conserved. One combination (JUN-FOS-BATF) especially improved cytotoxicity and in vivo persistence. The most impactful subdomains did not correlate with natural expression levels. Recombination of ETS and FOX family TF domains was also effective.

Contributed by Alex Najibi

Takacsi-Nagy et al. generated a library of synthetic T cell Transcription Factors (sTFs) through combinatorial assembly of AP-1 family TF subdomains. Expressed in CAR-T cells, certain sTFs improved CAR-T persistence/proliferation over natural TFs in a chronic stimulation assay. sTFs induced unique transcriptional and epigenetic T cell states from natural TFs, although their DNA binding sites were conserved. One combination (JUN-FOS-BATF) especially improved cytotoxicity and in vivo persistence. The most impactful subdomains did not correlate with natural expression levels. Recombination of ETS and FOX family TF domains was also effective.

Contributed by Alex Najibi

ABSTRACT: Human protein-coding genes evolved via rearrangement of domains from ancestral genes. We develop a scalable, evolutionarily guided method to assemble novel genes from constituent domains within a protein family, termed DESynR (domain engineered via synthesis and recombination) genes. In primary human T cells, DESynR activator protein-1 (AP-1) transcription factors (TFs) significantly outperform natural AP-1 TFs across in vitro and in vivo antitumor assays. DESynR AP-1 TFs induce broad transcriptional and epigenetic reprogramming and establish non-natural T cell states that optimize features of exhaustion, effector and cytotoxic function, and persistence-sometimes co-opting gene modules from disparate cell types. Reprogramming is primarily driven by differential regulation of established AP-1-bound regulatory elements rather than unique binding. Finally, we screen DESynR erythroblast transformation-specific (ETS) and forkhead box (FOX) TFs to support generalizability across protein families. Overall, we demonstrate that reconfiguring existing protein domains may uncover non-evolved genes that program therapeutically relevant cell states.

Author Info: (1) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA; Program in Immunology, Stanford Univer

Author Info: (1) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA; Program in Immunology, Stanford University, Stanford, CA, USA. (2) Center for Immunotherapy Design, Stanford University, Stanford, CA, USA; Division of Allergy, Immunology, and Rheumatology, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA. (3) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA; Department of Genetics, Stanford University, Stanford, CA, USA. (4) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA. (5) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA. (6) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA; Department of Bioengineering, Stanford University, Stanford, CA, USA. (7) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA. (8) Program in Immunology, Stanford University, Stanford, CA, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA; Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA. (9) Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA. (10) Department of Pathology, Stanford University, Stanford, CA, USA. (11) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA. (12) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA. (13) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA. (14) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA; Program in Immunology, Stanford University, Stanford, CA, USA. (15) Department of Pathology, Stanford University, Stanford, CA, USA. (16) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA. (17) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA; Program in Immunology, Stanford University, Stanford, CA, USA. (18) Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA. (19) Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA; Weill Cancer Hub West, Stanford, CA, USA. (20) Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA; Parker Institute for Cancer Immunotherapy, San Francisco, CA, USA; Weill Cancer Hub West, Stanford, CA, USA. (21) Parker Institute for Cancer Immunotherapy, San Francisco, CA, USA; Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA; Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA; Ludwig Center for Cancer Stem Cell Research and Medicine, Stanford University School of Medicine, Stanford, CA, USA; Weill Cancer Hub West, Stanford, CA, USA. (22) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA; Parker Institute for Cancer Immunotherapy, San Francisco, CA, USA; Weill Cancer Hub West, Stanford, CA, USA. Electronic address: troth@stanford.edu. (23) Department of Pathology, Stanford University, Stanford, CA, USA; Center for Immunotherapy Design, Stanford University, Stanford, CA, USA; Program in Immunology, Stanford University, Stanford, CA, USA; Parker Institute for Cancer Immunotherapy, San Francisco, CA, USA; Weill Cancer Hub West, Stanford, CA, USA. Electronic address: satpathy@stanford.edu.

A distinct antigen presentation pathway drives potent T cell immunity in lipid nanoparticle-based mRNA vaccines Spotlight 

Muro and Wang et al. studied mechanisms by which lipid nanoparticle-encapsulated mRNA (mRNA-LNP) vaccines induce significantly higher levels of antigen-specific cytotoxic T cells and T cell-dependent antibodies compared to conventional adjuvant-based immunization. Using model antigens, mRNA-LNP induced Th1-skewed murine CD4+ T cell differentiation, followed by production of class-switched IgGs (IgG2b and IgG2c) and long-term cytotoxic CD8+ T cells. Unlike traditional cDC1-mediated cross-presentation, mRNA-LNPs were primarily found in migratory cDC2 cells in draining lymph nodes, resulting in strong, persistent antigen presentation.

Contributed by Katherine Turner

Muro and Wang et al. studied mechanisms by which lipid nanoparticle-encapsulated mRNA (mRNA-LNP) vaccines induce significantly higher levels of antigen-specific cytotoxic T cells and T cell-dependent antibodies compared to conventional adjuvant-based immunization. Using model antigens, mRNA-LNP induced Th1-skewed murine CD4+ T cell differentiation, followed by production of class-switched IgGs (IgG2b and IgG2c) and long-term cytotoxic CD8+ T cells. Unlike traditional cDC1-mediated cross-presentation, mRNA-LNPs were primarily found in migratory cDC2 cells in draining lymph nodes, resulting in strong, persistent antigen presentation.

Contributed by Katherine Turner

ABSTRACT: Lipid nanoparticle-encapsulated mRNA (mRNA-LNP) vaccines trigger the potent differentiation of antigen-specific cytotoxic CD8 T cells in addition to antibody production. Despite its high immunogenicity, the cellular mechanisms by which mRNA-LNP induces such unusual immune responses remain largely unclear. Here, we show that mRNA-LNP induces potent and long-lasting CD8 T cell expansion through an antigen presentation mechanism that differs from that of conventional adjuvants. In mice immunized with mRNA-LNP, the number of antigen-specific CD8 T cells was one order of magnitude higher than that induced by combining antigen proteins with immunostimulants such as lipopolysaccharide or polyinosinic:polycytidinic acid. Intramuscularly administered mRNA-LNPs were mainly taken up by migratory type 2 conventional dendritic cells in draining lymph nodes, resulting in notably strong and persistent antigen presentation through major histocompatibility complex class I. Furthermore, CD8 T cell induction by mRNA-LNP required migratory dendritic cells but not the traditional cross-presentation pathway that is otherwise essential for antiviral and antitumor immunity. Thus, the mRNA-LNP formulation exerts unconventional immune responses through a different antigen-presentation pathway from conventional component vaccines.

Author Info: (1) Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan. Division of Molecular Pathology, Research Institute for Bi

Author Info: (1) Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan. Division of Molecular Pathology, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan. (2) Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan. (3) Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan. (4) Division of Molecular Pathology, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan. (5) Division of Vaccine Science, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan. International Vaccine Design Center, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan. Division of Rheumatology, Department of Medicine, University of California San Diego, La Jolla, CA, United States. (6) Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan. (7) Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan. Division of Immune Environment Dynamics, Cancer Research Institute, Kanazawa University, Kanazawa, Japan. Immune Network Research Unit, Institute for Frontier Science Initiative InFiniti, Kanazawa University, Kanazawa, Japan. (8) Department of Laboratory Animal Medicine, National Institute of Global Health and Medicine, Japan Institute for Health and Security (JIHS), Tokyo, Japan. (9) Department of Laboratory Animal Medicine, National Institute of Global Health and Medicine, Japan Institute for Health and Security (JIHS), Tokyo, Japan. (10) Kyoto University Immunomonitoring Center, Liaison Office, Kyoto University, Kyoto, Japan. Department of Immunology, Graduate School of Medicine, Kyoto University, Kyoto, Japan. (11) Division of Vaccine Science, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan. International Vaccine Design Center, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan. (12) Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan. Division of Molecular Pathology, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan. (13) Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan.

IL7-Receptor-Targeted CAR T-Cell Therapy for T-Cell Acute Lymphoblastic Leukemia Spotlight 

Hocine, Ganbaatar, and Amador-Molina et al. developed an IL7Rα (CD127)-targeted chimeric antigen receptor (CAR) T cells and demonstrated their efficacy against T-ALL in vitro and in vivo, including in a patient-derived xenograft model using matched patient-derived CAR T cells. Low-affinity CAR T cells outperformed high-affinity cells, but maintained higher expression of CD127, putting them at risk of fratricide after tumor eradication. To reduce fratricide, genetic KO of CD127, a natural selection method, and co-culture with dasatinib (a tyrosine kinase inhibitor), during manufacturing were each tested, with dasatinib emerging as the most viable option.

Contributed by Lauren Hitchings

Hocine, Ganbaatar, and Amador-Molina et al. developed an IL7Rα (CD127)-targeted chimeric antigen receptor (CAR) T cells and demonstrated their efficacy against T-ALL in vitro and in vivo, including in a patient-derived xenograft model using matched patient-derived CAR T cells. Low-affinity CAR T cells outperformed high-affinity cells, but maintained higher expression of CD127, putting them at risk of fratricide after tumor eradication. To reduce fratricide, genetic KO of CD127, a natural selection method, and co-culture with dasatinib (a tyrosine kinase inhibitor), during manufacturing were each tested, with dasatinib emerging as the most viable option.

Contributed by Lauren Hitchings

ABSTRACT: On the basis that T-cell acute lymphoblastic leukemia (T-ALL) cells overexpress IL7 receptor (IL7R), which promotes resistance to chemotherapy and disease relapse, here we develop IL7Rα (CD127)-targeted chimeric antigen receptor (CAR) T cells with low- and high-affinity single-chain variable fragments. We establish the antitumor efficacy of CD127 CAR against T-ALL cells in vitro, in female mouse models of T-ALL, and against blasts from patients with T-ALL using the patients' own T cells transduced with CD127 CAR. Antitumor efficacy is higher with low-affinity CAR T cells than high-affinity CAR T cells, albeit with fratricide of CAR T cells following eradication of CD127-overexpressing blasts. CRISPR-Cas9 knockout of CD127 eliminates fratricide at the risk of prolonged lymphopenia in vivo. To overcome fratricide, we investigate short-term ( < 7 days) co-culture with or without dasatinib, a tyrosine kinase inhibitor, versus a natural selection method (10 days) and demonstrate that co-culturing with dasatinib facilitates higher CAR T-cell yield, improved fitness, and preserved functionality. In vivo, dasatinib can be used to temporarily and reversibly suppress CAR T-cell activity. With this supporting translational data, we are initiating a trial with low-affinity CD127 CAR T cells for adult and pediatric patients with relapsed or refractory T-ALL.

Author Info: (1) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. (2) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer

Author Info: (1) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. (2) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. (3) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. (4) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. (5) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. (6) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. (7) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. (8) Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, New York, USA. (9) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. (10) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. (11) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. (12) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. (13) Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, New York, USA. (14) Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, New York, USA. (15) Cellular Therapy Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, USA. (16) Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, New York, USA. (17) Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. adusumip@mskcc.org. Cellular Therapy Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, USA. adusumip@mskcc.org.

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