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- Aleynick, Mark, et al.
(author)
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Pattern recognition receptor agonists in pathogen vaccines mediate antitumor T-cell cross-priming
- 2023
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In: Journal for ImmunoTherapy of Cancer. - : BMJ Publishing Group Ltd. - 2051-1426. ; 11:7
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Journal article (peer-reviewed)abstract
- Background Cancer immunotherapies are generallyeffective in patients whose tumors contain a prioriprimed T-cells reactive to tumor antigens (TA). Oneapproach to prime TA-reactive T-cells is to administerimmunostimulatory molecules, cells, or pathogens directlyto the tumor site, that is, in situ vaccination (ISV). Werecently described an ISV using Flt3L to expand and recruitdendritic cells (DC), radiotherapy to load DC with TA, andpattern recognition receptor agonists (PRRa) to activateTA-loaded DC. While ISV trials using synthetic PRRa haveyielded systemic tumor regressions, the optimal method toactivate DCs is unknown.Methods To discover optimal DC activators and increaseaccess to clinical grade reagents, we assessed whetherviral or bacterial components found in common pathogenvaccines are an effective source of natural PRRa(naPRRa). Using deep profiling (155-metric) of naPRRaimmunomodulatory effects and gene editing of specificPRR, we defined specific signatures and molecularmechanisms by which naPRRa potentiate T-cell priming.Results We observed that vaccine naPRRa can be evenmore potent in activating Flt3L-expanded murine andhuman DCs than synthetic PRRa, promoting cross-primingof TA-reactive T-cells. We developed a mechanisticallydiverse naPRRa combination (BCG, PedvaxHIB, Rabies)and noted more potent T-cell cross-priming than withany single naPRRa. The naPRRa triplet—as part of Flt3Lprimed ISV—induced greater intratumoral CD8 T-cellinfiltration, T-cells reactive to a newly defined tumorousneoantigen, durable tumor regressions.Conclusions This work provides rationale for thetranslation of pathogen vaccines as FDA-approved clinicalgrade DC activators which could be exploited as immunestimulants for early phase trials.
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| 2. |
- Svensson-Arvelund, Judit, 1982-, et al.
(author)
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Expanding cross-presenting dendritic cells enhances oncolytic virotherapy and is critical for long-term anti-tumor immunity
- 2022
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In: Nature Communications. - : Nature Portfolio. - 2041-1723. ; 13:1
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Journal article (peer-reviewed)abstract
- Immunotherapies directly enhancing anti-tumor CD8(+) T cell responses have yielded measurable but limited success, highlighting the need for alternatives. Anti-tumor T cell responses critically depend on antigen presenting dendritic cells (DC), and enhancing mobilization, antigen loading and activation of these cells represent an attractive possibility to potentiate T cell based therapies. Here we show that expansion of DCs by Flt3L administration impacts in situ vaccination with oncolytic Newcastle Disease Virus (NDV). Mechanistically, NDV activates DCs and sensitizes them to dying tumor cells through upregulation of dead-cell receptors and synergizes with Flt3L to promote anti-tumor CD8(+) T cell cross-priming. In vivo, Flt3L-NDV in situ vaccination induces parallel amplification of virus- and tumor-specific T cells, including CD8(+) T cells reactive to newly-described neoepitopes, promoting long-term tumor control. Cross-presenting conventional Type 1 DCs are indispensable for the anti-tumor, but not anti-viral, T cell response, and type I IFN-dependent CD4(+) Th1 effector cells contribute to optimal anti-tumor immunity. These data demonstrate that mobilizing DCs to increase tumor antigen cross-presentation improves oncolytic virotherapy and that neoepitope-specific T cells can be induced without individualized, ex vivo manufactured vaccines. Strategies to advance T cell based immune therapies are mostly focusing on the improvement of CD8 T cell effector functions, such as cytotoxicity or recruitment to the tumor. Here authors show that by combining in situ vaccination with oncolytic Newcastle Disease Virus and Flt3L-driven dendritic cell expansion, the anti-tumor T cell response is amplified via increased antigen cross-presentation.
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