Journal Articles

Tumor-induced dendritic cell deregulation perturbs T cell proliferation and predicts clinical outcome in acute lymphoblastic leukemia

Perturbations in dendritic cells (DCs) in B/T cell acute lymphoblastic leukemia (ALL), their cause(s) and consequence(s) on antileukemia immunity, and patient outcomes remain poorly explored. We find that maturation of DC1-6 subsets is disrupted in children and adults with ALL. Conventional DC1 and DC2 subpopulations are reduced at the expense of the progenitors and the DC4 fractions in ALL. The potential to mature, present antigens, and produce cytokines for initiating T cell surveillance appears to be impaired in every ALL DC subset. Such DC subsets are accordingly unable to induce T cell proliferation compared to DCs from healthy donors. MYC overexpression in ALL cells disrupts DC homeostasis and reduces the ability of DCs to induce T cell proliferation. Predominance of cells with transcriptional signatures typical of "stimulated DCs" predicts favorable clinical outcomes in B-ALL, while it is associated with unfavorable outcomes in T-ALL. Phenotyping DC subsets at ALL diagnosis could thus be valuable in informing treatment outcomes.

Author Info: (1) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (2) Department of Systems Biology, Beckman Research Institute of City of Hop

Author Info: (1) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (2) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (3) The Human Immune Monitoring Center (HIMC), Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford, CA 94305, USA. (4) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (5) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (6) Department of Molecular and Cellular Biology, City of Hope National Medical Center, Duarte, CA 91010, USA. (7) The Hematopoietic Tissue Biorepository/Research Pathology Shared Resources, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA. (8) Department of Pediatrics (Hematology and Oncology), Stanford University School of Medicine, Stanford, CA 94305, USA. (9) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (10) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (11) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. (12) The Hematopoietic Tissue Biorepository/Research Pathology Shared Resources, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA. (13) The Hematopoietic Tissue Biorepository/Research Pathology Shared Resources, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA; The Department of Hematological Malignancies Translational Science, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA. (14) Department of Pediatrics (Hematology and Oncology), Stanford University School of Medicine, Stanford, CA 94305, USA. (15) Department of Pediatrics (Hematology and Oncology), Stanford University School of Medicine, Stanford, CA 94305, USA. (16) Department of Basic Science, Division of Cancer Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA. (17) Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA. (18) Division of Oncology and Center for Childhood Cancer Research, Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Pediatrics and Abramson Cancer Center, University of Pennsylvania School of Medicine, Philadelphia, PA, USA. (19) Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA 94143, USA. (20) Department of Clinical Population and Public Health Sciences, University of Southern California, Los Angeles, CA 91016, USA. (21) Department of Pediatrics, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA. (22) Schneider Children's Medical Center, Tel Aviv University, Felsenstein Research Institute, Tel Aviv, Israel. (23) Department of Molecular and Cellular Biology, City of Hope National Medical Center, Duarte, CA 91010, USA. (24) The Human Immune Monitoring Center (HIMC), Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford, CA 94305, USA. (25) Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA; Department of Pediatrics, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA; Center for RNA Biology and Therapeutics, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA. Electronic address: sswaminathan@coh.org.

CCR7+ activated dendritic cells are essential for spontaneous and immunotherapy-driven anti-tumor immunity

Single-cell transcriptomics identifies a convergent activation state of conventional dendritic cells (cDCs) shared by type 1 and type 2 cDCs (cDC1s and cDC2s). These activated DCs (actDCs) are characterized by co-expression of T cell-stimulating and inhibitory molecules. Here, we examined the functional contribution of actDCs to anti-tumor immunity by developing mouse models that leverage CCR7 expression to conditionally label or ablate actDCs. The capacity of cDCs to stimulate tumor-specific cytotoxic T lymphocytes (CTLs) was restricted to the actDC state. cDC1- and cDC2-derived actDCs supported CTL priming through cross-presentation and cross-dressing, respectively, with the latter occurring in a cancer type-dependent manner. actDCs were required for the activation of naive CTLs in tumor-draining lymph nodes and for sustaining effector CTL function within tumors. Consequently, ablation of actDCs impaired spontaneous tumor control and responses to immune checkpoint blockade or adoptive T cell therapy. Thus, the actDC state emerges as a critical determinant of cDC-mediated anti-tumor immunity.

Author Info: (1) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (2) Cancer Inflammation and Immunity, Cancer Research U

Author Info: (1) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (2) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (3) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (4) Computational Biology Support, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (5) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (6) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (7) Flow Cytometry, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (8) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (9) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK; Dermatology Centre, Northern Care Alliance NHS Foundation Trust & Division of Musculoskeletal and Dermatological Sciences, Manchester NIHR Biomedical Research Centre, Manchester Academic Health Science Centre, The University of Manchester, Manchester, UK. (10) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (11) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (12) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (13) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (14) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (15) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (16) Computational Biology Support, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (17) Centre d'Etude des Pathologies Respiratoires, INSERM, UMR 1100, UniversitŽ de Tours, Tours, France. (18) Centre d'Immunologie de Marseille-Luminy, INSERM, CNRS, Aix Marseille UniversitŽ, Marseille, France; Centre d'ImmunophŽnomique, INSERM, CNRS, PHENOMIN, Celphedia, Aix Marseille UniversitŽ, Marseille, France. (19) Lydia Becker Institute of Immunology and Inflammation, The University of Manchester, Manchester, UK. (20) Genome Editing and Mouse Models, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK. (21) Cancer Inflammation and Immunity, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK; Lydia Becker Institute of Immunology and Inflammation, The University of Manchester, Manchester, UK. Electronic address: santiago.zelenay@cruk.manchester.ac.uk.

Dendritic cell circadian clocks shape memory CD8+ T cell differentiation

Circadian rhythms regulate diverse immune processes, yet how they influence memory CD8(+) T cell differentiation remains unclear. Here, we show that the time of day of antigen encounter shapes CD8(+) T cell fate and antiviral immunity. Immunization during the active phase promotes the generation of progenitor-like memory CD8(+) T cells and enhances T cell-mediated protection upon viral challenge. Mechanistically, dendritic cell-intrinsic circadian clocks regulate expression of the costimulatory ligand CD70, thereby directing T cell differentiation. These findings uncover a dendritic cell-mediated circadian mechanism that governs memory T cell fate decisions and suggest that aligning immune priming with circadian time may be leveraged to optimize T cell immunity.

Author Info: (1) Department of Immunology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands. (2) Department of Immunology, Leiden University Medical Center, Alb

Author Info: (1) Department of Immunology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands. (2) Department of Immunology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands. (3) Department of Immunology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands. (4) Department of Immunology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands. (5) Leiden University Center for Infectious Diseases, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands. (6) Leiden University Center for Infectious Diseases, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands. (7) Leiden University Center for Infectious Diseases, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands. (8) Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands. (9) Department of Immunology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.

CD4+ T cells play distinct roles during the priming versus effector phases of immune checkpoint therapy-dependent tumor elimination by CD8+ T cells Featured  

Ameh et al. studied the role of CD4+ T cells in mouse models during ICB treatment. CD4+ T cells were crucial for priming and effector phases to induce tumor rejection. During the effector phase, CD4+ T cells helped reinvigorate tumor-specific CD8+ T cells. CD40/CD40L signaling was vital for CD4+ T cell function during priming, while IL-2 and IFNγ were necessary for antitumor CD8+ T cell responses during the effector phase.

Ameh et al. studied the role of CD4+ T cells in mouse models during ICB treatment. CD4+ T cells were crucial for priming and effector phases to induce tumor rejection. During the effector phase, CD4+ T cells helped reinvigorate tumor-specific CD8+ T cells. CD40/CD40L signaling was vital for CD4+ T cell function during priming, while IL-2 and IFNγ were necessary for antitumor CD8+ T cell responses during the effector phase.

ABSTRACT: It is well established that CD4⁺ T cells play a critical role in facilitating immune checkpoint therapy (ICT). Although CD4+ T-cell function in lymph nodes during CD8⁺ T-cell priming has been well investigated, their requirement at the effector phase in the tumor is only now beginning to be appreciated. Herein, we used our major histocompatibility complex class II-negative (MHC-II-) sarcoma models to confirm that CD4⁺ T cells are essential not only during T-cell priming, but also to maintain T-cell effector function within the tumor. Depleting CD4⁺ T cells at the effector phase, after CD8+ T-cell priming had occurred, abolished ICT-induced tumor rejection despite the detection of tumor-specific CD8⁺ T cells and their intratumoral accumulation. CD4⁺ T cells were required for functional reinvigoration of CD8⁺ tumor-infiltrating lymphocytes (TIL) by ICT, leading to enhanced cytokine production, expression of cytotoxicity, and reduced exhaustion-without affecting CD8+ T-cell proliferation. Mechanistically, CD4⁺ T-cell function at the effector phase did not require CD40/CD40L signaling, which is necessary for efficient priming, but rather depended on IL-2 and IFNγ. Using a TCR-mimic monoclonal antibody (1G10) specific for the dominant neoantigen:I-Aᵇ complex on antigen-presenting cells formed during T3 sarcoma challenge, we further showed that ongoing MHC-II neoantigen presentation was necessary to sustain CD4⁺ T-cell help after priming. These findings reveal temporally distinct requirements for CD4⁺ T-cell help and establish a need for continuous CD4⁺/CD8⁺ T-cell cooperation as a prerequisite for anti-PD-1/anti-CTLA-4 ICT efficacy against MHC-II- tumors.

Author Info: (1) Washington University in St. Louis St. Louis, MO United States. ROR: https://ror.org/01yc7t268 (2) Washington University in St. Louis St. Louis, MO United States. ROR: https://

Author Info: (1) Washington University in St. Louis St. Louis, MO United States. ROR: https://ror.org/01yc7t268 (2) Washington University in St. Louis St. Louis, MO United States. ROR: https://ror.org/01yc7t268 (3) Washington University in St Louis St Louis United States. (4) Washington University in St. Louis St. Louis, MO United States. ROR: https://ror.org/01yc7t268 (5) Washington University in St. Louis St. Louis, MO United States. ROR: https://ror.org/01yc7t268 (6) Washington University in St. Louis United States. ROR: https://ror.org/01yc7t268 (7) Washington University in St. Louis St. Louis, MO United States. ROR: https://ror.org/01yc7t268 (8) Washington University in St. Louis St. Louis, Missouri United States. ROR: https://ror.org/01yc7t268 (9) Washington University in St. Louis St. Louis, MO United States. ROR: https://ror.org/01yc7t268 (10) Washington University in St. Louis Saint Louis, MO United States. ROR: https://ror.org/01yc7t268 (11) Washington University in St. Louis St. Louis, MO United States. ROR: https://ror.org/01yc7t268 (12) Washington University in St. Louis St. Louis, MO United States. ROR: https://ror.org/01yc7t268 (13) Washington University in St. Louis St. Louis, Missouri United States. ROR: https://ror.org/01yc7t268 (14) Washington University in St. Louis St. Louis, Missouri United States. ROR: https://ror.org/01yc7t268 (15) Washington University in St. Louis St. Louis, Missouri United States. ROR: https://ror.org/01yc7t268 (16) Washington University in St. Louis St. Louis, MO United States. ROR: https://ror.org/01yc7t268

Tumor-infiltrating plasma cell profiling after PD-1 blockade reveals tumor-specific antibodies Spotlight 

Evaluating patient NSCLC tumors treated with neoadjuvant anti-PD-1 and enriched for tertiary lymphoid structures, Meyerhoff, Chen, and O’brien et al. used transcriptomic data to identify B cell populations, including CD138+ plasma cells, and then performed single-cell sequencing to identify tumor-targeting BCRs and generate recombinant antibodies. The lead antibody, PC-1, recognized citrullinated antigens on tumor and pro-tumor myeloid cells, dependent on their expression of the citrullination enzyme PAD2. Incorporation of PC-1 into a CAR T cell mediated tumor control in mouse models, without evidence of off-tumor toxicity.

Contributed by Lauren Hitchings

Evaluating patient NSCLC tumors treated with neoadjuvant anti-PD-1 and enriched for tertiary lymphoid structures, Meyerhoff, Chen, and O’brien et al. used transcriptomic data to identify B cell populations, including CD138+ plasma cells, and then performed single-cell sequencing to identify tumor-targeting BCRs and generate recombinant antibodies. The lead antibody, PC-1, recognized citrullinated antigens on tumor and pro-tumor myeloid cells, dependent on their expression of the citrullination enzyme PAD2. Incorporation of PC-1 into a CAR T cell mediated tumor control in mouse models, without evidence of off-tumor toxicity.

Contributed by Lauren Hitchings

ABSTRACT: The role of tumor-infiltrating B cells (TIL-Bs) in shaping anti-tumor responses in the context of immune checkpoint blockade remains incompletely understood. Here, we interrogate the humoral response in resected lung tumors from patients with non-small cell lung cancer (NSCLC) treated with neoadjuvant PD-1 blockade. We find that tumors orchestrate tertiary lymphoid structures with CD138(+) plasma cells, from which we clone recombinant monoclonal antibodies (mAbs) using B cell receptors (BCRs) exhibiting somatic hypermutation and class switching. Several mAbs bind cell-surface citrullinated proteins, characteristic of cancer cells. Chimeric antigen receptor (CAR) T redirected with the soluble chain fragment variable (scFv) of our lead candidate antibody (PC-1) specifically target tumor cells and tumor-promoting myeloid cells in vivo without off-target activity. Moreover, ablation of the citrullination enzyme PADI2 in tumor-bearing mice eliminates reactivity to PC-1 and cytotoxic killing by the CAR. Our results implicate a therapeutic potential for tumor-infiltrating plasma cells that may be harnessed for cancer treatment.

Author Info: (1) Division of Interventional Radiology, Department of Radiology, Duke University School of Medicine, Durham, NC 27710, USA. Electronic address: meyerhr@mskcc.org. (2) Division of

Author Info: (1) Division of Interventional Radiology, Department of Radiology, Duke University School of Medicine, Durham, NC 27710, USA. Electronic address: meyerhr@mskcc.org. (2) Division of Medical Oncology, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA. (3) Division of Medical Oncology, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA. (4) Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC 27710, USA. (5) Division of Medical Oncology, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA. (6) Division of Medical Oncology, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA. (7) Department of Biomedical Engineering, Duke University, Durham, NC 27710, USA. (8) Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA. (9) Division of Medical Oncology, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA. (10) Division of Medical Oncology, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA. (11) Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC 27710, USA. (12) Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC 27710, USA. (13) Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC 27710, USA. (14) Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. (15) Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA. (16) Department of Chemistry, Duke University, Durham, NC 27710, USA; Department of Computer Science, Duke University, Durham, NC 27710, USA. (17) Division of Medical Oncology, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA. (18) Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA. (19) Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA. (20) Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC 27710, USA. (21) Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC 27710, USA. (22) Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA; Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. (23) Division of Medical Oncology, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA. (24) Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC 27710, USA. (25) Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC 27710, USA; Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA; Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Electronic address: wilton.williams@duke.edu. (26) Division of Medical Oncology, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA. Electronic address: scott.antonia@duke.edu.

Tertiary lymphoid structures harbour stem-like tumour-specific T cells Spotlight 

Afeyan, Nagler, and Tu et al. investigated how tertiary lymphoid structures (TLSs) impact phenotypic properties of tumor-specific T cells in treatment-naive renal carcinoma (RCC). Compared to TLS- tumors, TLS+ tumors were associated with increased numbers of exhausted CD8+ T cells (Tex) as well as IFN-stimulated CD8+ T cells and proliferating T cells, although CD8+ T cells exhibited greater exhaustion in TLS- tumors. 12% of tumor-specific clonotypes in TLSs exhibited a stem-like progenitor exhausted phenotype (Tpex) associated with favorable antitumor immunity. CD163+ immunosuppressive TAMs mapped to TLS boundaries with Tex cells.

Contributed by Katherine Turner

Afeyan, Nagler, and Tu et al. investigated how tertiary lymphoid structures (TLSs) impact phenotypic properties of tumor-specific T cells in treatment-naive renal carcinoma (RCC). Compared to TLS- tumors, TLS+ tumors were associated with increased numbers of exhausted CD8+ T cells (Tex) as well as IFN-stimulated CD8+ T cells and proliferating T cells, although CD8+ T cells exhibited greater exhaustion in TLS- tumors. 12% of tumor-specific clonotypes in TLSs exhibited a stem-like progenitor exhausted phenotype (Tpex) associated with favorable antitumor immunity. CD163+ immunosuppressive TAMs mapped to TLS boundaries with Tex cells.

Contributed by Katherine Turner

ABSTRACT: Tertiary lymphoid structures (TLSs) are associated with improved responses to immune checkpoint blockade across solid tumours(1,2), but how they impact the phenotypic properties of tumour-specific T cells remains unclear. Here we found, across 24 treatment-naive renal cell carcinoma (RCC) tumours, that TLS-containing tumours are more heavily infiltrated by exhausted CD8(+) T cells and have a reduced terminal exhaustion transcriptional program compared with TLS(-) tumours. Specificity screening of 554 T cell clonotypes expanded within the microenvironment of 6 RCC tumours revealed 82 TCRs that were reactive against tumour cells and/or RCC antigens. A subset of tumour-specific T cell clonotypes (12%) was enriched within TLSs, and these expressed an increased program of stem-like progenitor exhaustion, associated with favourable anti-tumour immunity. However, in 60 independent RCC tumours, macrophages within tumour margins of TLS-containing tumours had an inferred immunosuppressive phenotype and were colocalized with exhausted putative tumour-reactive T cells in a subgroup that was further analysed, therefore supporting this mode of immune evasion as a counterbalance to T cell immune pressure. Our data reveal that TLSs are reservoirs of tumour-specific T cells with stem-like progenitor features that could be leveraged by T cell immunotherapies.

Author Info: (1) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Harvard Medical School, Boston, MA, USA. (2) Department of Medical Oncology, Dana-Farber Cancer I

Author Info: (1) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Harvard Medical School, Boston, MA, USA. (2) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Broad Institute of MIT and Harvard, Cambridge, MA, USA. (3) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Department of Data Science, Dana-Farber Cancer Institute, Boston, MA, USA. (4) Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA. (5) Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA. (6) Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA. (7) Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA. (8) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. (9) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. (10) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Harvard Medical School, Boston, MA, USA. Broad Institute of MIT and Harvard, Cambridge, MA, USA. Centre for Immuno-Oncology, Nuffield Department of Medicine, University of Oxford, Oxford, UK. (11) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Broad Institute of MIT and Harvard, Cambridge, MA, USA. (12) Department of Data Science, Dana-Farber Cancer Institute, Boston, MA, USA. (13) Broad Institute of MIT and Harvard, Cambridge, MA, USA. Ragon Institute of MGB, MIT and Harvard, Cambridge, MA, USA. (14) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Harvard Medical School, Boston, MA, USA. Broad Institute of MIT and Harvard, Cambridge, MA, USA. (15) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Harvard Medical School, Boston, MA, USA. (16) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Broad Institute of MIT and Harvard, Cambridge, MA, USA. (17) University of Rochester Medical Center, Department of Pathology and Laboratory Medicine, Rochester, NY, USA. (18) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Broad Institute of MIT and Harvard, Cambridge, MA, USA. Translational Immunogenomics Laboratory, Dana-Farber Cancer Institute, Boston, MA, USA. (19) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Translational Immunogenomics Laboratory, Dana-Farber Cancer Institute, Boston, MA, USA. (20) Department of Data Science, Dana-Farber Cancer Institute, Boston, MA, USA. (21) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Harvard Medical School, Boston, MA, USA. Broad Institute of MIT and Harvard, Cambridge, MA, USA. Translational Immunogenomics Laboratory, Dana-Farber Cancer Institute, Boston, MA, USA. Department of Computer Science, Metropolitan College, Boston University, Boston, MA, USA. Section for Bioinformatics, Department of Health Technology, Technical University of Denmark, Lyngby, Denmark. (22) Broad Institute of MIT and Harvard, Cambridge, MA, USA. (23) Georgetown Lombardi Comprehensive Cancer Center, Washington, DC, USA. (24) Department of Data Science, Dana-Farber Cancer Institute, Boston, MA, USA. Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, MA, USA. (25) Harvard Medical School, Boston, MA, USA. Broad Institute of MIT and Harvard, Cambridge, MA, USA. Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA. Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA, USA. (26) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. giacomo_oliveira@dfci.harvard.edu. Harvard Medical School, Boston, MA, USA. giacomo_oliveira@dfci.harvard.edu. Broad Institute of MIT and Harvard, Cambridge, MA, USA. giacomo_oliveira@dfci.harvard.edu. (27) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. david.braun@yale.edu. Section of Medical Oncology, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA. david.braun@yale.edu. Center of Molecular and Cellular Oncology, Yale Cancer Center, Yale School of Medicine, New Haven, CT, USA. david.braun@yale.edu. (28) Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. catherine_wu@dfci.harvard.edu. Harvard Medical School, Boston, MA, USA. catherine_wu@dfci.harvard.edu. Broad Institute of MIT and Harvard, Cambridge, MA, USA. catherine_wu@dfci.harvard.edu.

Subclinical cholestasis is a hallmark of gut dysbiosis causing resistance to cancer immunotherapy

Spotlight 

Mallard de La Varende et al. showed that gut dysbiosis following treatment with antibiotics or antibiotic-associated species led to loss of secondary bile acids (BAs), increased tauro-conjugated primary BAs, downregulation of MAdCAM-1 in the ilium, and increased γ-glutamyl transferase (γ-GT) in serum, supporting TIME reprogramming, T cell exhaustion, and resistance to anti-PD-1 in tumor-bearing mice. Resistance could be overcome by performing FMT, supplementing secondary BAs, or using an ilium-specific FXR agonist. In patients, resistance was associated with subclinical cholestasis (elevated γ-GT), which predicted poor response.

Contributed by Lauren Hitchings

Mallard de La Varende et al. showed that gut dysbiosis following treatment with antibiotics or antibiotic-associated species led to loss of secondary bile acids (BAs), increased tauro-conjugated primary BAs, downregulation of MAdCAM-1 in the ilium, and increased γ-glutamyl transferase (γ-GT) in serum, supporting TIME reprogramming, T cell exhaustion, and resistance to anti-PD-1 in tumor-bearing mice. Resistance could be overcome by performing FMT, supplementing secondary BAs, or using an ilium-specific FXR agonist. In patients, resistance was associated with subclinical cholestasis (elevated γ-GT), which predicted poor response.

Contributed by Lauren Hitchings

ABSTRACT: Gut dysbiosis compromises cancer immunosurveillance by downregulating ileal mucosal addressin cell adhesion molecule 1 (MAdCAM-1), but the metabolic landscape associated with gut dysbiosis remains elusive. Here, we show that antibiotics (ABX) or ABX-associated Enterocloster species lead to the loss of secondary bile acids (BAs) including deoxycholic acid (DCA) and the accumulation of tauro-conjugated primary BAs (tauro-chenodeoxycholic acid [TCDCA] and tauro-β-muricholic acid [T-βMCA]) from the alternative pathway in the plasma of patients and mice. Fecal microbial transplantation (FMT), the ileum-specific farnesoid X receptor (FXR) agonist fexaramine, or glycodeoxycholic acid (GDCA) compen- sated dysbiosis-associated BA abnormalities and circumvent primary resistance to PD-1 blockade. GDCA curtailed ABX-induced MAdCAM-1 downregulation and T cell exhaustion in tumors. Subclinical cholestasis defined by elevation of γ-glutamyl transferase (γGT) correlated with increased TCDCA and decreased sMAdCAM-1 in plasma and predicted poor survival in multivariate analyses in six cohorts of patients who received immunotherapy. Hence, subclinical cholestasis accompanies gut dysbiosis, paving the way to immunoresistance.

Author Info: 1- Université Paris-Saclay, Gustave Roussy (GRCC), ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, 94805 Villejuif, France. 2- Centre de rec

Author Info: 1- Université Paris-Saclay, Gustave Roussy (GRCC), ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, 94805 Villejuif, France. 2- Centre de recherche Du CHUM (CRCHUM), Montréal, QC H2W1T8, Canada. 3- Centre de Recherche des Cordeliers, INSERM U1138, Equipe Labellisée – Ligue Nationale Contre le Cancer, Université Paris Cité, Sorbonne Université, 75006 Paris, France. 4- Unidad de Excelencia, Instituto de Biomedicina y Genética Molecular de Valladolid, Consejo Superior de Investigaciones Científicas-Universidad de Valladolid, 47001 Valladolid, Spain. 5- MetaGenoPolis, INRAe, Université Paris-Saclay 78350 Jouy en Josas, France. 6- Université Paris-Saclay, INSERM US23, Analyse moléculaire, modélisation et imagerie de la maladie Cancéreuse, Plateformes de Métabolomique et de Criblage Cellulaire Haut Débit, 94805 Villejuif, France. 7- Université Paris-Saclay, Gustave Roussy, U1356 Next Generation Immuno-Oncology Research, 94805 Villejuif, France

A Patient-Derived Screen Identifies HDAC Inhibitors as Enhancers of Phagocytosis and Potent Immunotherapy Partners Spotlight 

Khalaj et al. performed a small molecule screen of FDA-approved compounds on CD11b+ tumor-associated microglia/macrophages isolated from patient GBM, and identified histone deacetylase (HDAC) inhibitors as enhancers of TAM phagocytosis. HDAC inhibitors increased phagocytosis across multiple TAM-GBM pairs, and showed synergy with CD47 blockade ex vivo. In an orthotopic patient-derived GBM xenograft model, Pracinostat combined with anti-CD47 slowed tumor growth and extended survival. Pracinostat reprogrammed TAMs toward an NF-κB-driven inflammatory state, and epigenetically primed FcγR-mediated phagocytic machinery.

Contributed by Shishir Pant

Khalaj et al. performed a small molecule screen of FDA-approved compounds on CD11b+ tumor-associated microglia/macrophages isolated from patient GBM, and identified histone deacetylase (HDAC) inhibitors as enhancers of TAM phagocytosis. HDAC inhibitors increased phagocytosis across multiple TAM-GBM pairs, and showed synergy with CD47 blockade ex vivo. In an orthotopic patient-derived GBM xenograft model, Pracinostat combined with anti-CD47 slowed tumor growth and extended survival. Pracinostat reprogrammed TAMs toward an NF-κB-driven inflammatory state, and epigenetically primed FcγR-mediated phagocytic machinery.

Contributed by Shishir Pant

ABSTRACT: Glioblastoma multiforme (GBM) is a lethal brain tumor with limited treatment options. Tumor-associated macrophages and microglia (TAMs) drive immune suppression and tumor progression, making them a key therapeutic target for GBM. Enhancing TAM phagocytosis in GBM has shown promise, particularly with innate checkpoint inhibitors, such as CD47-blocking antibodies. However, small molecule approaches, which offer tunable and potentially synergistic mechanisms, remain underexplored in this context. In this study, we conducted a large-scale small molecule screen on primary TAMs isolated directly from GBM patient tumors, testing 1,365 compounds to identify drugs that enhance TAM phagocytosis. This screen revealed enrichment for histone deacetylase (HDAC)-targeting drugs among the top hits. HDAC inhibitors enhanced phagocytosis of cancer cells across multiple primary human TAM-GBM combinations, and synergized with CD47 blockade ex vivo. In a xenograft GBM model, Pracinostat suppressed tumor growth and extended survival, with additive benefit when combined with CD47 antibodies. RNA-sequencing and H3K27Ac CUT&Tag profiling of Pracinostat-treated TAMs in vivo revealed a two-tier mechanism: transcriptional reprogramming toward a pro-inflammatory state via NF-κB activation, and epigenetic priming of FcγR-mediated phagocytic machinery, providing a mechanistic basis for the observed synergy with CD47 blockade. Our findings establish a patient-first functional screening platform for identifying TAM-reprogramming therapeutics in GBM, validate HDAC inhibitors as a lead class that potentiates innate checkpoint immunotherapy, and provide additional candidate compounds for clinical investigation.

Author Info: (1) Stanford Medicine Stanford United States. ROR: https://ror.org/03mtd9a03 (2) Stanford Medicine United States. ROR: https://ror.org/03mtd9a03 (3) University of California, San F

Author Info: (1) Stanford Medicine Stanford United States. ROR: https://ror.org/03mtd9a03 (2) Stanford Medicine United States. ROR: https://ror.org/03mtd9a03 (3) University of California, San Francisco San Francisco United States. ROR: https://ror.org/043mz5j54 (4) University of California San Francisco Medical Center San Francisco United States. ROR: https://ror.org/01t8svj65 (5) Stanford Medicine Stanford United States. ROR: https://ror.org/03mtd9a03 (6) Stanford University California 94305-5439, CA United States. ROR: https://ror.org/00f54p054 (7) University of California, San Francisco San Francisco, CA United States. ROR: https://ror.org/043mz5j54 (8) University of California, San Francisco San Francisco, CA United States. ROR: https://ror.org/043mz5j54 (9) Stanford University Stanford University, CA United States. ROR: https://ror.org/00f54p054

Tim-3 Sustains Tumor Treg Stability and Function, Limiting Checkpoint Blockade Therapy Efficacy Spotlight 

Banerjee et al. showed that Tim3 expression on tumor-infiltrating Tregs was required for their survival and suppressive function via Akt-FOXO1 signaling. Treg-specific Tim3 deletion in an MC38 model reduced tumor-infiltrating Tregs and CD25 expression, impaired Treg survival, delayed CD8+ T cell exhaustion, enhanced CD8+ proliferation, and reduced tumor burden, without disrupting peripheral homeostasis. Delayed Tim3 deletion in Tregs was sufficient to slow tumor growth and augment CD8+ responses, and Treg-specific Tim3 loss synergized with ICB in a resistant B16F10 model. In HNSCC, low Tim3 expression correlated with response to anti-PD-1/Lag3 ICB.

Contributed by Shishir Pant

Banerjee et al. showed that Tim3 expression on tumor-infiltrating Tregs was required for their survival and suppressive function via Akt-FOXO1 signaling. Treg-specific Tim3 deletion in an MC38 model reduced tumor-infiltrating Tregs and CD25 expression, impaired Treg survival, delayed CD8+ T cell exhaustion, enhanced CD8+ proliferation, and reduced tumor burden, without disrupting peripheral homeostasis. Delayed Tim3 deletion in Tregs was sufficient to slow tumor growth and augment CD8+ responses, and Treg-specific Tim3 loss synergized with ICB in a resistant B16F10 model. In HNSCC, low Tim3 expression correlated with response to anti-PD-1/Lag3 ICB.

Contributed by Shishir Pant

ABSTRACT: Regulatory T cells (Treg) act as a powerful barrier to effective antitumor immunity. Although manipulating Treg is a promising anticancer strategy, doing so while sparing general immune tolerance has been a challenge. Identifying factors specifically expressed in tumor-infiltrating Treg is therefore important for better understanding cancer pathogenesis and identifying novel therapeutic targets that enhance antitumor immunity. We show that T cell Immunoglobulin and Mucin 3 (Tim-3) expression on tumor Treg is required for the function and survival of these cells, in part through Akt and FOXO1 signaling. Deleting Tim-3 in Treg leads to delayed tumor-specific T-cell exhaustion and lower tumor burden, without altering peripheral homeostasis. Similar effects were noted when Tim-3 was only deleted from half of the Treg or when deletion was delayed until after tumor inoculation. Moreover, Treg-specific deletion of Tim-3 cooperated with PD-1 checkpoint blockade to sensitize an immunotherapy-resistant tumor model. In addition, a decrease in Tim-3+ tumor Treg correlated with responsiveness to PD-1/LAG-3 combination checkpoint blockade in a human clinical trial. Overall, our data provide evidence that Tim3-expressing Treg are a promising target to modulate tumor-specific immune responses.

Author Info: (1) University of Pittsburgh Pittsburgh, PA United States. ROR: https://ror.org/01an3r305 (2) University of Pittsburgh Pittsburgh, PA United States. ROR: https://ror.org/01an3r305

Author Info: (1) University of Pittsburgh Pittsburgh, PA United States. ROR: https://ror.org/01an3r305 (2) University of Pittsburgh Pittsburgh, PA United States. ROR: https://ror.org/01an3r305 (3) University of Pittsburgh Pittsburgh, PA United States. ROR: https://ror.org/01an3r305 (4) University of Pittsburgh Pittsburgh, PA United States. ROR: https://ror.org/01an3r305 (5) University of North Carolina at Chapel Hill Chapel Hill, NC United States. ROR: https://ror.org/0130frc33 (6) University of Pittsburgh Pittsburgh, PA United States. ROR: https://ror.org/01an3r305 (7) University of Pittsburgh Pittsburgh, PA United States. ROR: https://ror.org/01an3r305 (8) University of Pittsburgh Pittsburgh, PA United States. ROR: https://ror.org/01an3r305 (9) University of Pittsburgh Pittsburgh, PA United States. (10) University of North Carolina at Chapel Hill Chapel Hill, NC United States. ROR: https://ror.org/0130frc33 (11) University of Pittsburgh Pittsburgh, PA United States. ROR: https://ror.org/01an3r305 (12) University of North Carolina Hospitals Chapel Hill, NC United States. ROR: https://ror.org/0355zfr67 (13) University of Pittsburgh Pittsburgh, PA United States. ROR: https://ror.org/01an3r305

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.

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