Journal Articles

DF6215, an α-optimized IL-2-Fc fusion, expands immune effectors and drives robust preclinical anti-tumor activity

Spotlight 

Stockmann et al. engineered DF6215, comprised of two truncated IgG1 Fc chains (which bind FcRn, but not FcγR) fused at one Fc C terminus to an IL-2 mutein with reduced IL-2Rα (modest) and IL-2Rαβγ (23-fold) binding, increased IL-2Rβ binding (3.5-fold), and enhanced IL-2Rβγ signaling compared to WT IL-2. DF6215 preferentially expanded murine tumor-infiltrating CD8+ T and NK cells over Tregs, induced robust dose-dependent regression of solid tumors as monotherapy, and synergized with anti-PD-1. In NHPs, DF6215 showed an extended serum half-life and favorable safety and pharmacodynamics relative to aldesleukin. DF6215 is now in Phase 1/2 testing.

Contributed by Paula Hochman

Stockmann et al. engineered DF6215, comprised of two truncated IgG1 Fc chains (which bind FcRn, but not FcγR) fused at one Fc C terminus to an IL-2 mutein with reduced IL-2Rα (modest) and IL-2Rαβγ (23-fold) binding, increased IL-2Rβ binding (3.5-fold), and enhanced IL-2Rβγ signaling compared to WT IL-2. DF6215 preferentially expanded murine tumor-infiltrating CD8+ T and NK cells over Tregs, induced robust dose-dependent regression of solid tumors as monotherapy, and synergized with anti-PD-1. In NHPs, DF6215 showed an extended serum half-life and favorable safety and pharmacodynamics relative to aldesleukin. DF6215 is now in Phase 1/2 testing.

Contributed by Paula Hochman

ABSTRACT: DF6215 is a rationally engineered interleukin-2 (IL-2) Fc-fusion protein developed to overcome efficacy and safety limitations of traditional IL-2 cancer immunotherapy. Unlike non-alpha (non-α) IL-2 variants that eliminate CD25 binding and underperform clinically, DF6215 retains moderate IL-2 receptor α (IL-2Rα) affinity while enhancing IL-2Rβγ signaling and extending the half-life via an engineered immunoglobulin (Ig)G1 Fc domain. This design preferentially expands cytotoxic CD8+ T cells and natural killer cells over regulatory T cells, resulting in favorable effector-to-regulatory cell ratios, enhanced immune activation, and robust tumor regression in mouse models. In poorly immunogenic tumors, DF6215 synergized with PD-1 blockade to achieve durable responses without added toxicity. Cynomolgus monkey studies confirm DF6215's pharmacodynamics and favorable safety profile, with no signs of vascular leak syndrome or cytokine release syndrome. These findings position DF6215 as a differentiated IL-2 capable of modulating the tumor microenvironment and achieving potent anti-tumor immunity with improved tolerability, supporting its advancement into clinical trials for solid tumors.

Author Info: (1) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (2) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (3) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (4) Dr

Author Info: (1) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (2) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (3) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (4) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (5) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (6) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (7) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (8) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (9) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (10) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (11) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. (12) Dragonfly Therapeutics, Inc., Waltham, MA 02451, USA. Electronic address: ann.cheung@dragonflytx.com.

Tissue-resident exhausted and memory CD8+ T cells have distinct ontogeny, function and role in disease

Spotlight 

Park et al. showed that chronic antigen exposure drove a distinct lineage of tissue-resident exhausted CD8+ T cells (TR-TEX) that was developmentally and functionally separate from tissue-resident memory (TRM) cells formed after antigen clearance. TR-TEX (Tox-dependent) and TRM (Tox-independent) cells shared residency features, but were governed by divergent transcriptional and epigenetic programs. TRM cells retained plasticity to differentiate into TEX cells under chronic stimulation, while committed TEX cells failed to generate TRM cells after antigen withdrawal. TR-TEX cells responded to PD-1 pathway blockade in vivo, and were associated with patient responses to ICB.

Contributed by Shishir Pant

Park et al. showed that chronic antigen exposure drove a distinct lineage of tissue-resident exhausted CD8+ T cells (TR-TEX) that was developmentally and functionally separate from tissue-resident memory (TRM) cells formed after antigen clearance. TR-TEX (Tox-dependent) and TRM (Tox-independent) cells shared residency features, but were governed by divergent transcriptional and epigenetic programs. TRM cells retained plasticity to differentiate into TEX cells under chronic stimulation, while committed TEX cells failed to generate TRM cells after antigen withdrawal. TR-TEX cells responded to PD-1 pathway blockade in vivo, and were associated with patient responses to ICB.

Contributed by Shishir Pant

ABSTRACT: The presence of CD8(+) T cells coexpressing residency and exhaustion molecules in chronic diseases often correlate with clinical outcomes; however, the relationship between these cells and conventional tissue-resident memory (T(RM)) cells or exhausted CD8(+) T (T(EX)) cells is unclear. Here we show that chronic antigen stimulation drives development of tissue-resident T(EX) (TR-T(EX)) cells that are distinct from T(RM) cells generated after antigen clearance. TR-T(EX) and T(RM) cells are regulated by different transcriptional networks with only TR-T(EX) cells being Tox-dependent for residency programming. While T(EX) cells (including TR-T(EX)) are unable to generate T(RM) cells after antigen withdrawal, T(RM) cells differentiate into T(EX) cells upon chronic antigen exposure. Cell-state-specific transcriptional signatures reveal a selective association of TR-T(EX) cells with patient responses to immune checkpoint blockade, and only TR-T(EX) but not T(RM) cells responded to PD-1 pathway inhibition in vivo. These data suggest that TR-T(EX) and T(RM) cells are developmentally divergent cell states that share a tissue-residency program but have distinct roles in disease control.

Author Info: (1) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. simone.park@pennmedicine.upen

Author Info: (1) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. simone.park@pennmedicine.upenn.edu. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. simone.park@pennmedicine.upenn.edu. (2) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (3) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (4) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (5) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (6) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, USA. (7) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Parker Institute for Cancer Immunotherapy at University of Pennsylvania, Philadelphia, PA, USA. (8) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Center for Cellular Immunotherapies, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (9) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Parker Institute for Cancer Immunotherapy at University of Pennsylvania, Philadelphia, PA, USA. (10) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Department of Medicine II (Gastroenterology, Hepatology, Endocrinology and Infectious Diseases), Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany. (11) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (12) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (13) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Parker Institute for Cancer Immunotherapy at University of Pennsylvania, Philadelphia, PA, USA. (14) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (15) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (16) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Parker Institute for Cancer Immunotherapy at University of Pennsylvania, Philadelphia, PA, USA. (17) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, USA. (18) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Department of Medicine, Massachusetts General Hospital, Boston, MA, USA. (19) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (20) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Parker Institute for Cancer Immunotherapy at University of Pennsylvania, Philadelphia, PA, USA. (21) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Center for Cellular Immunotherapies, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (22) Center for Cellular Immunotherapies, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (23) Center for Cellular Immunotherapies, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (24) Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Department of Medicine: Hematology and Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (25) Department of Otorhinolaryngology: Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (26) Department of Otorhinolaryngology: Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (27) Department of Otorhinolaryngology: Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (28) Department of Otorhinolaryngology: Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (29) Department of Otorhinolaryngology: Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (30) Department of Otorhinolaryngology: Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (31) Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Department of Otorhinolaryngology: Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (32) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Parker Institute for Cancer Immunotherapy at University of Pennsylvania, Philadelphia, PA, USA. (33) Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. wherry@pennmedicine.upenn.edu. Institute for Immunology and Immune Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. wherry@pennmedicine.upenn.edu. Parker Institute for Cancer Immunotherapy at University of Pennsylvania, Philadelphia, PA, USA. wherry@pennmedicine.upenn.edu.

Autologous multiantigen-targeted T cell therapy for pancreatic cancer: a phase 1/2 trial Spotlight 

37 patients with PDAC received ex vivo-expanded T cells that had been stimulated by DCs presenting peptides from 5 known TAAs. Tested polyclonal T cell products specifically responded to TAAs, comprised newly detected TCR clonotypes, and had memory phenotypes. Treatment was generally safe, and disease control rates were 84.6% and 25.0% in patients who did or did not, respectively, respond to first-line chemotherapy. Infused T cells persisted out to 1 year, and the frequency of TAA-specific T cells was higher in responders than in non-responders. Antigen spreading, polyfunctionality, and tumor infiltration were observed. 2 patients with resectable disease were relapse-free >5 years.

Contributed by Alex Najibi

37 patients with PDAC received ex vivo-expanded T cells that had been stimulated by DCs presenting peptides from 5 known TAAs. Tested polyclonal T cell products specifically responded to TAAs, comprised newly detected TCR clonotypes, and had memory phenotypes. Treatment was generally safe, and disease control rates were 84.6% and 25.0% in patients who did or did not, respectively, respond to first-line chemotherapy. Infused T cells persisted out to 1 year, and the frequency of TAA-specific T cells was higher in responders than in non-responders. Antigen spreading, polyfunctionality, and tumor infiltration were observed. 2 patients with resectable disease were relapse-free >5 years.

Contributed by Alex Najibi

ABSTRACT: T cell therapy has proven challenging for pancreatic ductal adenocarcinoma (PDAC), partly due to heterogeneous expression of tumor-associated antigens (TAAs). To address tumor heterogeneity and mitigate immune evasion, an ex vivo expanded, polyclonal, T helper 1 cell-polarized T cell product targeting five TAAs-PRAME, SSX2, MAGEA4, Survivin and NY-ESO-1-was developed. These antigens were chosen based on their tumor specificity, oncogenicity, immunogenicity and level of expression. In a phase 1/2 trial, this autologous nonengineered T cell product was administered (1 × 107 cells m-2 per infusion) monthly to patients with advanced PDAC responding (arm A, n = 13) or refractory (arm B, n = 12) to first-line chemotherapy or with resectable disease (arm C, n = 12). Primary endpoints were safety and feasibility of completing six infusions, whereas exploratory efficacy endpoints included persistence and evaluating the relationship between clinical benefit and the expansion of the infused effector T cells, as well as the induction of de novo immune responses. Of 56 participants procured, 37 were infused, with only 1 treatment-related serious adverse event. Disease control rates in arms A and B were 84.6% (95% confidence interval: 54.6-98.1%) and 25% (95% confidence interval: 5.5-57.2%), respectively. In arm C, two of nine resected participants remained disease free after 66 months of follow-up. The infused cells persisted up to 12 months posttreatment and elevated levels of tumor-directed T cells were detected during dosing (P = 0.027) and follow-up in responders compared to nonresponders. Clinical outcomes correlated with peripheral expansion of functional TAA-targeted T cell clones and treatment-emergent antigen spreading. Thus, further investigation of this approach, either as a single agent or combined with other complementary modalities, is warranted (ClinicalTrials.gov identifier: NCT03192462 ).

Author Info: (1) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, U

Author Info: (1) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. blmusher@bcm.edu. (2) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (3) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (4) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (5) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (6) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (7) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (8) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (9) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (10) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (11) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (12) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (13) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (14) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (15) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (16) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (17) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (18) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (19) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (20) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. (21) Center for Cell and Gene Therapy, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX, USA. aleen@bcm.edu.

Cross-presentation of dead cell-associated antigens shapes the neoantigenic landscape of tumor immunity Featured  

Lim, Schulz, et al. studied the functioning of the F-actin receptor DNGR-1 on cDC1s, and the impact of cross-presentation on immunoediting of tumors using chemical carcinogenesis models. Dead cell-associated antigens anchored to F-actin were found to be cross-presented by cDC1s to CD8+ T cells, in a process dependent on DNGR-1 signaling. Loss of this DNGR-1-mediated cross-presentation resulted in faster tumor growth and limited priming of T cells specific for F-actin-binding proteins (FABP). This FABP neoantigen cross-presentation by cDC1s impacted immune visibility and immunoediting of tumors.

Lim, Schulz, et al. studied the functioning of the F-actin receptor DNGR-1 on cDC1s, and the impact of cross-presentation on immunoediting of tumors using chemical carcinogenesis models. Dead cell-associated antigens anchored to F-actin were found to be cross-presented by cDC1s to CD8+ T cells, in a process dependent on DNGR-1 signaling. Loss of this DNGR-1-mediated cross-presentation resulted in faster tumor growth and limited priming of T cells specific for F-actin-binding proteins (FABP). This FABP neoantigen cross-presentation by cDC1s impacted immune visibility and immunoediting of tumors.

ABSTRACT: Type 1 conventional dendritic cells (cDC1s) acquire and cross-present tumor antigens to prime CD8⁺ T cells. Whether this selects for specific neoantigens is unclear. DNGR-1 (CLEC9A), a cDC1 receptor for F-actin exposed on dead cells, promotes cross-presentation of cell-associated antigens. Here we show that DNGR-1-deficient mice develop chemically induced tumors more rapidly and at higher incidence, and these are more frequently rejected on transplantation into wild-type recipients. Whole-exome sequencing reveals enrichment of predicted neoantigens derived from mutated F-actin-binding proteins. Consistent with this observation, tethering model antigens to F-actin enhances DNGR-1-dependent cross-presentation. These results suggest that DNGR-1-mediated recognition of F-actin exposed by dead cancer cells favors priming of CD8⁺ T cells specific for cytoskeletal neoantigens, which can then drive immune escape of cancer cells lacking or reverting those mutations. Thus, neoantigen cross-presentation by cDC1 can determine the immune visibility of the tumor mutational landscape and sculpt cancer evolution by immunoediting.

Author Info: (1) Immunobiology Laboratory, The Francis Crick Institute, London, UK. Department of Immunology and Inflammation, Imperial College London, London, UK. Cancer Dynamics Laboratory, T

Author Info: (1) Immunobiology Laboratory, The Francis Crick Institute, London, UK. Department of Immunology and Inflammation, Imperial College London, London, UK. Cancer Dynamics Laboratory, The Francis Crick Institute, London, UK. Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK. Advanced Immunotherapy and Cell Therapy Team, The Christie NHS Foundation Trust, Manchester, UK. (2) Immunobiology Laboratory, The Francis Crick Institute, London, UK. (3) Cancer Dynamics Laboratory, The Francis Crick Institute, London, UK. (4) Immunobiology Laboratory, The Francis Crick Institute, London, UK. (5) Centre for Evolution and Cancer, Institute of Cancer Research, London, UK. Center for Mathematical Modelling, Universidad de Chile, Santiago, Chile. (6) Immunobiology Laboratory, The Francis Crick Institute, London, UK. Cancer Immunosurveillance Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (7) Immunobiology Laboratory, The Francis Crick Institute, London, UK. Early Oncology Research and Development, AstraZeneca, Cambridge, UK. (8) Immunobiology Laboratory, The Francis Crick Institute, London, UK. (9) Immunobiology Laboratory, The Francis Crick Institute, London, UK. (10) Immunobiology Laboratory, The Francis Crick Institute, London, UK. (11) Bioinformatics and Biostatistics, The Francis Crick Institute, London, UK. (12) Bioinformatics and Biostatistics, The Francis Crick Institute, London, UK. (13) Immunobiology Laboratory, The Francis Crick Institute, London, UK. (14) Immunobiology Laboratory, The Francis Crick Institute, London, UK. Medical Department, ADM Health and Wellness, London, UK. (15) Immunobiology Laboratory, The Francis Crick Institute, London, UK. (16) Apple Tree Partners, Cambridge, USA. (17) Apple Tree Partners, Cambridge, USA. (18) Adendra Therapeutics Ltd., London, UK. (19) Department of Immunology and Inflammation, Imperial College London, London, UK. (20) Cancer Dynamics Laboratory, The Francis Crick Institute, London, UK. Skin and Renal Unit, The Royal Marsden NHS Foundation Trust, London, UK. Cancer Dynamics Laboratory, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. The Christie NHS Foundation Trust, Manchester, UK. (21) Immunobiology Laboratory, The Francis Crick Institute, London, UK. caetano@crick.ac.uk.

Intratumoral delivery of FLT3L with CXCR3/CCR5 ligands promotes XCR1+ cDC1 infiltration and activates anti-tumor immunity

Spotlight 

To overcome active inhibition of cDC1 recruitment to tumors, Gorline and Rosa do Carmo et al. showed that mesenchymal stromal cells (MSC), engineered to express the membrane-bound form of FLT3L and delivered intratumorally, required pIC activation of CCL5 and CXCL9 to enhance the migration of DCs into tumors and to draining lymph nodes. Antigen cross-presentation, infiltration of T and NK cells, T cell activation, and synergy with ICB were all increased. Expression of the chemokines in the FLT3L-engineered MSC replaced the need for pIC, replicating the benefit. Engineered MSCs expressing the human factors enhanced DC engraftment in a humanized mouse model.

Contributed by Ed Fritsch

To overcome active inhibition of cDC1 recruitment to tumors, Gorline and Rosa do Carmo et al. showed that mesenchymal stromal cells (MSC), engineered to express the membrane-bound form of FLT3L and delivered intratumorally, required pIC activation of CCL5 and CXCL9 to enhance the migration of DCs into tumors and to draining lymph nodes. Antigen cross-presentation, infiltration of T and NK cells, T cell activation, and synergy with ICB were all increased. Expression of the chemokines in the FLT3L-engineered MSC replaced the need for pIC, replicating the benefit. Engineered MSCs expressing the human factors enhanced DC engraftment in a humanized mouse model.

Contributed by Ed Fritsch

ABSTRACT: Tumor infiltration by XCR1⁺ conventional dendritic cells (cDC1) correlates strongly with favorable prognosis and improved responses to immunotherapy. Yet, tumor-driven immunosuppressive programs restrict efficient cDC1 recruitment, highlighting the need for strategies to increase cDC1 access to the tumor microenvironment. Here, we establish a proof-of-concept cell-based immunotherapy that enhances the infiltration of circulating cDC1 progenitors and supports their local expansion. Intratumoral engraftment of autologous mesenchymal stromal cells engineered to express membrane bound FLT3L promotes cDC1 recruitment when combined with poly(I:C). We identify poly(I:C)-induced CXCL9 and CCL5 as essential chemokines controlling intratumoral cDC1 infiltration. Stromal cell-mediated local delivery of FLT3L together with CXCL9 and CCL5 is sufficient to enhance cDC1 infiltration in mice or humanized mice settings. Finally, this approach activates antitumor immunity and partially overcomes resistance to immune checkpoint blockade. Collectively, our data support the therapeutic potential of expanding intratumoral cDC1s through local and sustained delivery of FLT3L, CXCL9, and CCL5.

Author Info: (1) Dendritic Cells and Adaptive Immunity Unit, Immunology Department, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. CNRS UMR3738, Developmental Biology and Stem Cells

Author Info: (1) Dendritic Cells and Adaptive Immunity Unit, Immunology Department, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. CNRS UMR3738, Developmental Biology and Stem Cells, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. Centre for Vaccine and Immunotherapy, Institut Pasteur, Paris, France. (2) Dendritic Cells and Adaptive Immunity Unit, Immunology Department, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. CNRS UMR3738, Developmental Biology and Stem Cells, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. Centre for Vaccine and Immunotherapy, Institut Pasteur, Paris, France. (3) Laboratory of Tumor Inflammation and Angiogenesis, Center for Cancer Biology, VIB, Leuven, Belgium. INSERM UMR 1016, CNRS UMR 8104, Institut Cochin, UniversitŽ Paris CitŽ, Paris, France. (4) Dendritic Cells and Adaptive Immunity Unit, Immunology Department, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. CNRS UMR3738, Developmental Biology and Stem Cells, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. Centre for Vaccine and Immunotherapy, Institut Pasteur, Paris, France. (5) Dendritic Cells and Adaptive Immunity Unit, Immunology Department, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. CNRS UMR3738, Developmental Biology and Stem Cells, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. Centre for Vaccine and Immunotherapy, Institut Pasteur, Paris, France. (6) Dendritic Cells and Adaptive Immunity Unit, Immunology Department, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. CNRS UMR3738, Developmental Biology and Stem Cells, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. Centre for Vaccine and Immunotherapy, Institut Pasteur, Paris, France. INSERM UMR 1016, CNRS UMR 8104, Institut Cochin, UniversitŽ Paris CitŽ, Paris, France. (7) Bichat Medical School, INSERM UMR1149, CNRS EMR8252, UniversitŽ Paris CitŽ, Paris, France. (8) Dendritic Cells and Adaptive Immunity Unit, Immunology Department, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. CNRS UMR3738, Developmental Biology and Stem Cells, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. Centre for Vaccine and Immunotherapy, Institut Pasteur, Paris, France. (9) Dendritic Cells and Adaptive Immunity Unit, Immunology Department, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. CNRS UMR3738, Developmental Biology and Stem Cells, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. Centre for Vaccine and Immunotherapy, Institut Pasteur, Paris, France. (10) Bichat Medical School, INSERM UMR1149, CNRS EMR8252, UniversitŽ Paris CitŽ, Paris, France. (11) Department of Pathology and Immunology, Geneva Medical School, Geneva, Switzerland. (12) Human Disease Models Core Facility, Institut Pasteur, UniversitŽ Paris CitŽ, Paris, France. (13) Human Disease Models Core Facility, Institut Pasteur, UniversitŽ Paris CitŽ, Paris, France. (14) Nutrition and Obesity: Systemic Approaches, Inserm, Sorbonne University, Paris, France. (15) Dendritic Cells and Adaptive Immunity Unit, Immunology Department, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. CNRS UMR3738, Developmental Biology and Stem Cells, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. Centre for Vaccine and Immunotherapy, Institut Pasteur, Paris, France. (16) INSERM UMR 1016, CNRS UMR 8104, Institut Cochin, UniversitŽ Paris CitŽ, Paris, France. (17) INSERM UMR 1016, CNRS UMR 8104, Institut Cochin, UniversitŽ Paris CitŽ, Paris, France. (18) Inserm U1015, Institut Gustave Roussy, UniversitŽ Paris-Saclay, Villejuif, France. (19) Inserm Transfert, Paris, France. (20) Inserm Transfert, Paris, France. (21) Deparment of Cellular Immunology, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy. (22) Department of Pathology and Immunology, Geneva Medical School, Geneva, Switzerland. (23) Inserm U1015, Institut Gustave Roussy, UniversitŽ Paris-Saclay, Villejuif, France. (24) Virology Department, Pasteur-TheraVectys Joint Laboratory, Institut Pasteur, UniversitŽ Paris CitŽ, Paris, France. (25) Nutrition and Obesity: Systemic Approaches, Inserm, Sorbonne University, Paris, France. (26) Bichat Medical School, INSERM UMR1149, CNRS EMR8252, UniversitŽ Paris CitŽ, Paris, France. (27) INSERM UMR 1016, CNRS UMR 8104, Institut Cochin, UniversitŽ Paris CitŽ, Paris, France. (28) Centre d'Immunologie de Marseille-Luminy, CIML, CNRS, INSERM, Aix Marseille UniversitŽ, Marseille, France. (29) Human Disease Models Core Facility, Institut Pasteur, UniversitŽ Paris CitŽ, Paris, France. (30) Centre for Vaccine and Immunotherapy, Institut Pasteur, Paris, France. Immunology Department, ImmunitŽ InnŽe, Institut Pasteur, Paris, France. (31) Department of Pathology and Immunology, Geneva Medical School, Geneva, Switzerland. (32) Dendritic Cells and Adaptive Immunity Unit, Immunology Department, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. pierre.guermonprez@pasteur.fr. CNRS UMR3738, Developmental Biology and Stem Cells, Institut Pasteur, UniversitŽ de Paris CitŽ, Paris, France. pierre.guermonprez@pasteur.fr. Centre for Vaccine and Immunotherapy, Institut Pasteur, Paris, France. pierre.guermonprez@pasteur.fr.

CD27 agonism enhances long-lived CD4 T cell vaccine responses critical for antitumor immunity Spotlight 

To mechanistically understand better vaccine efficacy, Hwang et al. conducted a retrospective analysis of long-term (>18 years) breast cancer survivors who received HER2+ targeted autologous DC vaccines. PBMC analysis revealed that all patients had persistent CD27+ HER2-specific memory CD4+ and CD8+ T cells, suggesting a key role for CD27 in supporting long-term immune memory. In human-CD27-transgenic mice, primary HER2 vaccination combined with an agonist anti-CD27 mAb expanded HER2-specific CD27+ memory T cell populations in the TME and boosted antitumor responses. CD4+ (but not CD8+) T cells were essential for agonist CD27 efficacy.

Contributed by Katherine Turner

To mechanistically understand better vaccine efficacy, Hwang et al. conducted a retrospective analysis of long-term (>18 years) breast cancer survivors who received HER2+ targeted autologous DC vaccines. PBMC analysis revealed that all patients had persistent CD27+ HER2-specific memory CD4+ and CD8+ T cells, suggesting a key role for CD27 in supporting long-term immune memory. In human-CD27-transgenic mice, primary HER2 vaccination combined with an agonist anti-CD27 mAb expanded HER2-specific CD27+ memory T cell populations in the TME and boosted antitumor responses. CD4+ (but not CD8+) T cells were essential for agonist CD27 efficacy.

Contributed by Katherine Turner

ABSTRACT: Tumor antigen vaccination represents an appealing approach for cancer but has failed to materialize as oncologic standard of care. To understand long-term vaccine efficacy, we conducted a retrospective analysis of patients with human epidermal growth receptor 2(+) (HER2(+)) breast cancer who received HER2-targeting vaccines and survived for >18 years. PBMC analysis revealed HER2-specific CD27(+) memory CD4 and CD8 T cells, suggesting that CD27 signaling supports long-term immune memory. In human CD27 transgenic mice, combining HER2 vaccination with anti-CD27 agonism enhanced HER2-specific responses, particularly long-lived CD4 memory T cells. Murine models demonstrated ~40% tumor regression with combined therapy compared with vaccine alone (~6%). Additional scRNA-seq analysis identified CD4 T cells with a distinct gene expression profile, and depletion/adoptive transfer studies validated that CD4 T cells were essential for this effect. These findings suggest that CD27 agonism enhances vaccine-induced antigen-specific CD4 T cell responses, enabling durable antitumor immunity not entirely dependent on CD8 T cells.

Author Info: (1) Department of Surgery, Duke University, Durham, NC, USA. (2) Department of Surgery, Duke University, Durham, NC, USA. Department of Integrative Immunobiology, Duke University,

Author Info: (1) Department of Surgery, Duke University, Durham, NC, USA. (2) Department of Surgery, Duke University, Durham, NC, USA. Department of Integrative Immunobiology, Duke University, Durham, NC, USA. (3) Department of Surgery, Duke University, Durham, NC, USA. (4) Department of Surgery, Duke University, Durham, NC, USA. (5) Department of Surgery, Duke University, Durham, NC, USA. (6) Department of Surgery, Duke University, Durham, NC, USA. (7) Department of Surgery, Duke University, Durham, NC, USA. (8) Department of Surgery, Duke University, Durham, NC, USA. (9) Department of Surgery, Duke University, Durham, NC, USA. (10) Department of Surgery, Duke University, Durham, NC, USA. (11) Department of Surgery, Duke University, Durham, NC, USA. (12) Department of Surgery, Duke University, Durham, NC, USA. Department of Pathology, Duke University, Durham, NC, USA. (13) Department of Surgery, Duke University, Durham, NC, USA. (14) Department of Surgery, Duke University, Durham, NC, USA. (15) Department of Medicine, Duke University, Durham, NC, USA. (16) Department of Surgery, Duke University, Durham, NC, USA. (17) School of Medicine, Duke University, Durham, NC, USA. (18) Department of Surgery, Duke University, Durham, NC, USA. (19) Department of Surgery, Duke University, Durham, NC, USA. (20) Celldex Therapeutics Inc., Hampton, NJ, USA. (21) Celldex Therapeutics Inc., Hampton, NJ, USA. (22) Department of Surgery, Duke University, Durham, NC, USA. Department of Integrative Immunobiology, Duke University, Durham, NC, USA. Department of Pathology, Duke University, Durham, NC, USA. (23) Department of Surgery, Duke University, Durham, NC, USA. Department of Integrative Immunobiology, Duke University, Durham, NC, USA. Department of Pathology, Duke University, Durham, NC, USA.

Targeting LRBA triggers CTLA4 degradation and antitumor immunity for cancer immunotherapy Spotlight 

Ge et al. developed LC427, a small molecule inhibitor of LRBA, a CTLA-4-stabilizing protein that was negatively correlated with antitumor immunity in patient samples. LC427 blocked intracellular LRBA binding to CTLA-4, which diminished T cell CTLA-4, in part via lysosomal degradation. LC427 decreased T cell apoptosis, enhanced NF-κB signaling, and improved tumor cell killing and antitumor efficacy, comparable to anti-CTLA-4. LC427 activity was dependent on CD8+ T cells and LRBA/CTLA-4 interactions in T cells; LRBA or CTLA-4 deficiency abolished LC427 efficacy. LC427 was better tolerated than anti-CTLA-4 in the inflammatory DSS colitis model.

Contributed by Morgan Janes

Ge et al. developed LC427, a small molecule inhibitor of LRBA, a CTLA-4-stabilizing protein that was negatively correlated with antitumor immunity in patient samples. LC427 blocked intracellular LRBA binding to CTLA-4, which diminished T cell CTLA-4, in part via lysosomal degradation. LC427 decreased T cell apoptosis, enhanced NF-κB signaling, and improved tumor cell killing and antitumor efficacy, comparable to anti-CTLA-4. LC427 activity was dependent on CD8+ T cells and LRBA/CTLA-4 interactions in T cells; LRBA or CTLA-4 deficiency abolished LC427 efficacy. LC427 was better tolerated than anti-CTLA-4 in the inflammatory DSS colitis model.

Contributed by Morgan Janes

ABSTRACT: The lipopolysaccharide-responsive beige-like anchor protein (LRBA) deficiency causes severe autoimmune diseases and cytotoxic T-lymphocyte-associated protein 4 (CTLA4) loss in humans. However, the impact of LRBA on antitumor immunity remains understudied. Here we show the important role of LRBA in antitumor immunity and develop small molecules targeting LRBA for cancer immunotherapy. Interestingly, LRBA is negatively associated with antitumor immunity in human patients and mouse models. Using high-throughput screening and subsequent hit optimization, we discover a small molecule LC427 that facilitates the lysosomal degradation of CTLA4 and bolsters survival of activated T cells by binding directly to LRBA and inhibiting the LRBA-CTLA4 interaction. Orally administrated LC427 increases tumor-infiltrating CD8(+) T cells and displays effective antitumor activity in multiple mouse tumor models. Notably, LC427 does not induce immune-related adverse events observed with immune checkpoint inhibitors in colitis models. Our study demonstrates that targeting LRBA offers an effective strategy for cancer immunotherapy.

Author Info: (1) Laboratory of Molecular Pharmacology and Drug Discovery, Institute of Chinese Materia Medica, The Fourth Clinical Medical College, Guangzhou University of Chinese Medicine; Sha

Author Info: (1) Laboratory of Molecular Pharmacology and Drug Discovery, Institute of Chinese Materia Medica, The Fourth Clinical Medical College, Guangzhou University of Chinese Medicine; Shanghai Key Laboratory of Pancreatic Disease, Department of Gastroenterology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201620, China. (2) Department of Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201620, China. (3) Laboratory of Molecular Pharmacology and Drug Discovery, Institute of Chinese Materia Medica, The Fourth Clinical Medical College, Guangzhou University of Chinese Medicine; Shanghai Key Laboratory of Pancreatic Disease, Department of Gastroenterology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201620, China. (4) Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai, 200032, China. (5) Laboratory of Molecular Pharmacology and Drug Discovery, Institute of Chinese Materia Medica, The Fourth Clinical Medical College, Guangzhou University of Chinese Medicine; Shanghai Key Laboratory of Pancreatic Disease, Department of Gastroenterology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201620, China. (6) Department of Radiotherapy, Shenzhen Traditional Chinese Medicine Hospital, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen, Guangdong, 518033, China. (7) Department of Neurology and Psychology, Shenzhen Traditional Chinese Medicine Hospital, The Fourth Clinical Medical College, Guangzhou University of Chinese Medicine, Shenzhen, Guangdong, 518033, China. (8) Department of Medical Laboratory Science, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China. (9) Suzhou Guokuang Pharm Tech. Co., Ltd, Suzhou, Jiangsu, 215000, China. (10) Suzhou Guokuang Pharm Tech. Co., Ltd, Suzhou, Jiangsu, 215000, China. (11) Suzhou Guokuang Pharm Tech. Co., Ltd, Suzhou, Jiangsu, 215000, China. (12) School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China. (13) Department of Medical Laboratory Science, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China. (14) The International Eye Research Institute of The Chinese University of Hong Kong (Shenzhen); C-MER Dennis Lam & Partners Eye Center, C-MER International Eye Care Group, Hong Kong, 999077, China. (15) Biomedical Translational Research Institute, School of Life Sciences and Medicine, Shandong University of Technology, Zibo, Shandong, 255049, China. (16) Biomedical Translational Research Institute, School of Life Sciences and Medicine, Shandong University of Technology, Zibo, Shandong, 255049, China. (17) Laboratory of Cancer Genomics and Biology, Department of Urology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201620, China. (18) Noble Life Sciences Inc, Sykesville, Maryland, 21784, USA. (19) Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, Beijing, 100850, China. gaoyue@bmi.ac.cn. (20) Laboratory of Molecular Pharmacology and Drug Discovery, Institute of Chinese Materia Medica, The Fourth Clinical Medical College, Guangzhou University of Chinese Medicine; Shanghai Key Laboratory of Pancreatic Disease, Department of Gastroenterology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201620, China. hbk3397@gzucm.edu.cn.

T cell priming by high avidity neoantigens in lymph nodes augments adoptive immunotherapy Spotlight 

To study how neoantigen avidity impacts T cell function in adoptive cell therapy (ACT), Wittling et al. compared antitumor responses of naive transgenic pmel-1 CD8+ T cells transferred into a B16F10 melanoma model expressing either low-avidity gp100 (wild-type) or a high-avidity mutant gp100 (EGS to KVP) neoantigen. Compared to wild-type, high-avidity KVP neoantigen was sufficient to activate naive CD8+ T cells, leading to enhanced cytokine production, increased effector function, sustained persistence, robust tumor regression, and long-term immunity, even in the absence of host T and B cells. Early lymph node trafficking was essential for ACT efficacy.

Contributed by Katherine Turner

To study how neoantigen avidity impacts T cell function in adoptive cell therapy (ACT), Wittling et al. compared antitumor responses of naive transgenic pmel-1 CD8+ T cells transferred into a B16F10 melanoma model expressing either low-avidity gp100 (wild-type) or a high-avidity mutant gp100 (EGS to KVP) neoantigen. Compared to wild-type, high-avidity KVP neoantigen was sufficient to activate naive CD8+ T cells, leading to enhanced cytokine production, increased effector function, sustained persistence, robust tumor regression, and long-term immunity, even in the absence of host T and B cells. Early lymph node trafficking was essential for ACT efficacy.

Contributed by Katherine Turner

ABSTRACT: Adoptive transfer of T lymphocytes specific for tumor-associated neoantigens can elicit immunity against solid tumors in patients. However, how these antigens impact T cell function, effector differentiation, and persistence remains unclear. We examined how an identical CD8+ T cell product was shaped by melanoma expressing either a low-avidity tumor-associated antigen or high-avidity neoantigen, and kinetically profiled T cell differentiation in these two contexts across host tissues. High-avidity neoantigen expression was sufficient to activate naïve CD8+ T cells - leading to robust tumor regression and long-term protective immunity upon tumor rechallenge. Mechanistically, transferred naïve CD8+ T cells reacting to high-avidity neoantigen exhibited enhanced cytokine production, heightened effector function, and sustained persistence compared to the low-avidity wild-type tumors. Antitumor activity to these high-avidity tumors was preserved even in the absence of functional host T and B lymphocytes, and early lymph node trafficking was found to be essential for ACT efficacy. Expanded effector or stem-memory T cells were compared to the naïve pmel-1 T cell product. Stem-memory but not effector-memory cells exhibited similar antitumor efficacy and lymph node trafficking patterns to the naïve cells in mice with high-avidity neoantigen tumors. These findings highlight how differential tumor antigens shape divergent cellular fate and uncover a critical role of T cell trafficking in lymph nodes in shaping high-avidity neoantigen-specific antitumor responses.

Author Info: (1) Emory University, Atlanta, GA, United States. (2) Emory University, Atlanta, GA, United States. (3) Emory University, Atlanta, GA, United States. (4) Emory University, Atlanta,

Author Info: (1) Emory University, Atlanta, GA, United States. (2) Emory University, Atlanta, GA, United States. (3) Emory University, Atlanta, GA, United States. (4) Emory University, Atlanta, GA, United States. (5) Emory University, Atlanta, Georgia, United States. (6) Medical University of South Carolina, Charleston, SC, United States. (7) Emory University, Atlanta, GA, United States. (8) Emory University, Atlanta, GA, United States. (9) Emory University, Atlanta, GA, United States. (10) Emory University, Atlanta, GA, United States. (11) Emory University, Atlanta, GA, United States. (12) Werewolf Therapeutics, Watertown, MA, United States. (13) Lumicks, Amsterdam, Netherlands. (14) Emory University, Atlanta, GA, United States. (15) Winship Cancer Institute, Atlanta, GA, United States. (16) Emory University, Atlanta, GA, United States. (17) Stanford University, Palo Alto, CA, United States.

Potentiating immunotherapy in "immune-cold" solid tumors through orchestrating T cell immunity via tumor-specific genetic engineering Spotlight 

He et al. engineered an i.v.-delivered nanoparticle containing a plasmid PαCD3&LIGHT, in which a TERT promoter drives tumor-restricted αCD3 and LIGHT expression to reprogram T cell immunity in the TME of immune-cold solid tumors. LIGHT induced HEV formation, chemokine secretion, ECM remodeling, and T cell infiltration, while αCD3 established artificial immunological synapses, amplified TCR signaling, and reinvigorated exhausted T cells. PαCD3&LIGHT suppressed multiple immune-cold solid tumor mouse models and enhanced ICB and CAR T cell efficacy, without obvious systemic toxicity. A humanized construct enhanced human CAR T activity, without systemic toxicity.

Contributed by Shishir Pant

He et al. engineered an i.v.-delivered nanoparticle containing a plasmid PαCD3&LIGHT, in which a TERT promoter drives tumor-restricted αCD3 and LIGHT expression to reprogram T cell immunity in the TME of immune-cold solid tumors. LIGHT induced HEV formation, chemokine secretion, ECM remodeling, and T cell infiltration, while αCD3 established artificial immunological synapses, amplified TCR signaling, and reinvigorated exhausted T cells. PαCD3&LIGHT suppressed multiple immune-cold solid tumor mouse models and enhanced ICB and CAR T cell efficacy, without obvious systemic toxicity. A humanized construct enhanced human CAR T activity, without systemic toxicity.

Contributed by Shishir Pant

ABSTRACT: We engineer a tumor-targeted genetic plasmid vector (P(_CD3&LIGHT)) to systematically modulate T cell immunity. The tumor-specific telomerase reverse transcriptase (TERT) promoter drives simultaneous expression of tumor necrosis factor superfamily member 14 (LIGHT) and membrane-anchored anti-CD3 single-chain variable fragment (_CD3), which are important immunomodulators with closely clinical relevance. Secreted LIGHT induces high endothelial venule formation and chemokine secretion to recruit circulating lymphocytes, while remodeling extracellular matrix to facilitate immune cell penetration into tumor parenchyma. _CD3 establishes artificial immunological synapses between tumor cells and T lymphocytes. This dual mechanism synergistically establishes tertiary lymphoid structures de novo even within deep tumor regions, harboring stem cell-like CD8(+) T cells and driving sustained immunity. Concurrently, _CD3-mediated T cell redirection not only amplifies TCR signaling but also reverses exhausted T cells. The orchestrated T cell immunity significantly potentiates checkpoint inhibitor and chimeric antigen receptor (CAR)-T cell therapies in "immune-cold" tumors without obvious side effects and also remarkably enhances the outcome of human CAR-T cells, demonstrating translational potential in solid tumor immunotherapy.

Author Info: (1) School of Life Science, Beijing Institute of Technology, Beijing 100081, China. (2) State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chines

Author Info: (1) School of Life Science, Beijing Institute of Technology, Beijing 100081, China. (2) State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China. (3) School of Life Science, Beijing Institute of Technology, Beijing 100081, China. (4) School of Medical Technology, Beijing Institute of Technology, Beijing 100081, China. (5) Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital and Institute, Beijing 100142, China. (6) Department of Respiratory and Digestive, Qian'an Yanshan Hospital, Tangshan 064400, China. (7) Department of Otorhinolaryngology, Qian'an Yanshan Hospital, Tangshan 064400, China. (8) State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Chemical Biology Center, Peking University, Beijing 100191, China. (9) School of Medical Technology, Beijing Institute of Technology, Beijing 100081, China. (10) School of Life Science, Beijing Institute of Technology, Beijing 100081, China. (11) State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Chemical Biology Center, Peking University, Beijing 100191, China. (12) School of Life Science, Beijing Institute of Technology, Beijing 100081, China. Electronic address: victornia@bit.edu.cn. (13) State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Chemical Biology Center, Peking University, Beijing 100191, China; Peking University Ningbo Institute of Marine Medicine, Ningbo 315832, China. Electronic address: hyanxie@bjmu.edu.cn.

A universal boosting strategy for adoptive T cell therapy using a paired vaccine/chimeric antigen receptor Spotlight 

Burchett et al. investigated various vaccine-based approaches to boost the effects of CMV gp33-targeted (P14) TCR T cells in a solid tumor model, particularly focused on a CAR/vaccine combination targeting a “universal” surrogate epitope (BCMA). A VSV-based vaccine expressing surface BCMA (but not a secreted BCMA-Ig-Fc) expanded the BCMACAR_P14 T cells at day 5, but persistence was very limited. Early tumor responses and a survival benefit, but no cures, were observed. VSV-induced IFN-I limited gp33 expression, but blocking IFNAR1 had minimal impact on persistence. Gp33-stimulation of P14 cells through the TCR enhanced persistence, induced endogenous T cells, and eliminated gp33+ tumor cells.

Contributed by Ed Fritsch

Burchett et al. investigated various vaccine-based approaches to boost the effects of CMV gp33-targeted (P14) TCR T cells in a solid tumor model, particularly focused on a CAR/vaccine combination targeting a “universal” surrogate epitope (BCMA). A VSV-based vaccine expressing surface BCMA (but not a secreted BCMA-Ig-Fc) expanded the BCMACAR_P14 T cells at day 5, but persistence was very limited. Early tumor responses and a survival benefit, but no cures, were observed. VSV-induced IFN-I limited gp33 expression, but blocking IFNAR1 had minimal impact on persistence. Gp33-stimulation of P14 cells through the TCR enhanced persistence, induced endogenous T cells, and eliminated gp33+ tumor cells.

Contributed by Ed Fritsch

ABSTRACT: Vaccines that encode tumour-associated antigens are potent boosting agents for adoptively transferred tumour-specific T cells. Employing vaccines to boost adoptively transferred tumour-reactive T cells relies on a priori knowledge of tumour epitopes, isolation of matched epitope-specific T cells, and personalized vaccines, all of which limit clinical feasibility. Here, we investigated a universal strategy for boosting transferred tumour-specific T cells where boosting is provided through a chimeric antigen receptor (CAR) that is paired with a vaccine encoding the CAR target antigen. To this end, we developed and employed a model wherein murine T cells expressing a TCR specific for antigen on syngeneic tumours were engineered with boosting CARs against a distinct surrogate boosting antigen for studies in immunocompetent hosts. Boosting CAR-engineered tumour-specific T cells with paired vesicular stomatitis virus (VSV) vaccines was associated with robust T cell expansion and delayed tumour progression in the absence of prior lymphodepletion. CAR-T cell expansion and antitumour function was further enhanced by blocking IFNAR1. However, vaccine-boosted CAR-T cells rapidly contracted and antigen-positive tumours re-emerged. In contrast, when the same T cells were boosted with a vaccine encoding antigen that stimulates through the TCR, the adoptively transferred T cells displayed improved persistence, tumour-specific endogenous cells expanded in parallel, and tumour cells carrying the antigen target were completely eradicated. Our findings underscore the need for further research into CAR-mediated vaccine boosting, how this differs mechanistically from TCR-mediated boosting, and the importance of engaging endogenous tumour-reactive T cells during vaccination to achieve long-term tumour control.

Author Info: (1) McMaster University, Hamilton, ON, Canada. (2) McMaster University, Hamilton, Ontario, Canada. (3) McMaster University, Hamilton, Ontario, Canada. (4) McMaster University, Hami

Author Info: (1) McMaster University, Hamilton, ON, Canada. (2) McMaster University, Hamilton, Ontario, Canada. (3) McMaster University, Hamilton, Ontario, Canada. (4) McMaster University, Hamilton, ON, Canada. (5) McMaster University, Hamilton, Ontario, Canada. (6) McMaster University, Hamilton, ON, Canada. (7) Ottawa Hospital Research Institute, Ottawa, Ontario, Canada. (8) McMaster University, Hamilton, Ontario, Canada. (9) McMaster University, Hamilton, ON, Canada. (10) Ottawa Hospital Research Institute, Ottawa, Ontario, Canada. (11) McMaster University, Hamilton, Ontario, Canada. (12) McMaster University, Hamilton, Canada. (13) McMaster University, Hamilton, Ontario, Canada. (14) McMaster University, Hamilton, ON, Canada. (15) McMaster University, Hamilton, Ontario, Canada.

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