Abstract
Indolent non-Hodgkin's lymphomas (iNHLs) are incurable with standard therapy and are poorly responsive to checkpoint blockade. Although lymphoma cells are efficiently killed by primed T cells, in vivo priming of anti-lymphoma T cells has been elusive. Here, we demonstrate that lymphoma cells can directly prime T cells, but in vivo immunity still requires cross-presentation. To address this, we developed an in situ vaccine (ISV), combining Flt3L, radiotherapy, and a TLR3 agonist, which recruited, antigen-loaded and activated intratumoral, cross-presenting dendritic cells (DCs). ISV induced anti-tumor CD8+ T cell responses and systemic (abscopal) cancer remission in patients with advanced stage iNHL in an ongoing trial ( NCT01976585 ). Non-responding patients developed a population of PD1+CD8+ T cells after ISV, and murine tumors became newly responsive to PD1 blockade, prompting a follow-up trial of the combined therapy. Our data substantiate that recruiting and activating intratumoral, cross-priming DCs is achievable and critical to anti-tumor T cell responses and PD1-blockade efficacy.
Publication types
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Clinical Trial, Phase I
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Clinical Trial, Phase II
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adult
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Aged
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Animals
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Antigen Presentation
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CD8-Positive T-Lymphocytes / immunology
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Cancer Vaccines*
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Carboxymethylcellulose Sodium / analogs & derivatives
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Carboxymethylcellulose Sodium / therapeutic use
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Cell Line, Tumor
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Combined Modality Therapy
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Dendritic Cells / immunology
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Female
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Humans
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Immunotherapy, Adoptive
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Lymphoma, B-Cell / immunology
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Lymphoma, B-Cell / pathology
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Lymphoma, B-Cell / therapy*
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Male
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Membrane Proteins / immunology
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Mice
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Mice, Inbred BALB C
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Mice, Inbred C57BL
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Mice, Knockout
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Middle Aged
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Poly I-C / therapeutic use
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Polylysine / analogs & derivatives
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Polylysine / therapeutic use
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Programmed Cell Death 1 Receptor / antagonists & inhibitors
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Programmed Cell Death 1 Receptor / immunology
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Toll-Like Receptor 3 / agonists
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Vaccination
Substances
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Cancer Vaccines
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Membrane Proteins
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PDCD1 protein, human
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Programmed Cell Death 1 Receptor
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TLR3 protein, human
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Toll-Like Receptor 3
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flt3 ligand protein
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Polylysine
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poly ICLC
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Carboxymethylcellulose Sodium
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Poly I-C