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Adoptive immunotherapy combined with intratumoral TLR agonist delivery eradicates established melanoma in mice.

ABSTRACT: Toll-like receptor (TLR) agonists can trigger broad inflammatory responses that elicit rapid innate immunity and promote the activities of lymphocytes, which can potentially enhance adoptive immunotherapy in the tumor-bearing setting. In the present study, we found that Polyinosinic:Polycytidylic Acid [Poly(I:C)] and CpG oligodeoxynucleotide 1826 [CpG], agonists for TLR 3 and 9, respectively, potently activated adoptively transferred T cells against a murine model of established melanoma. Intratumoral injection of Poly(I:C) and CpG, combined with systemic transfer of activated pmel-1 T cells, specific for gp100(25-33), led to enhanced survival and eradication of 9-day established subcutaneous B16F10 melanomas in a proportion of mice. A series of survival studies in knockout mice supported a key mechanistic pathway, whereby TLR agonists acted via host cells to enhance IFN-? production by adoptively transferred T cells. IFN-?, in turn, enhanced the immunogenicity of the B16F10 melanoma line, leading to increased killing by adoptively transferred T cells. Thus, this combination approach counteracted tumor escape from immunotherapy via downregulation of immunogenicity. In conclusion, TLR agonists may represent advanced adjuvants within the setting of adoptive T-cell immunotherapy of cancer and hold promise as a safe means of enhancing this approach within the clinic.

SUBMITTER: Amos SM

PROVIDER: S-EPMC3499620 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature

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Adoptive immunotherapy combined with intratumoral TLR agonist delivery eradicates established melanoma in mice.

Amos Sally M SM Pegram Hollie J HJ Westwood Jennifer A JA John Liza B LB Devaud Christel C Clarke Chris J CJ Restifo Nicholas P NP Smyth Mark J MJ Darcy Phillip K PK Kershaw Michael H MH

Cancer immunology, immunotherapy : CII 20110216 5

Toll-like receptor (TLR) agonists can trigger broad inflammatory responses that elicit rapid innate immunity and promote the activities of lymphocytes, which can potentially enhance adoptive immunotherapy in the tumor-bearing setting. In the present study, we found that Polyinosinic:Polycytidylic Acid [Poly(I:C)] and CpG oligodeoxynucleotide 1826 [CpG], agonists for TLR 3 and 9, respectively, potently activated adoptively transferred T cells against a murine model of established melanoma. Intrat ...[more]

PMID: 21327636

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Project description:BackgroundImmune checkpoint blockade (ICB) promotes adaptive immunity and tumor regression in some cancer patients. However, in patients with immunologically "cold" tumors, tumor-resident innate immune cell activation may be required to prime an adaptive immune response and so exploit the full potential of ICB. Whilst Toll-like receptor (TLR) agonists have been used topically to successfully treat some superficial skin tumors, systemic TLR agonists have not been well-tolerated.MethodsThe response of human immune cells to TLR7 and 8 agonism was measured in primary human immune cell assays. MEDI9197 (3M-052) was designed as a novel lipophilic TLR7/8 agonist that is retained at the injection site, limiting systemic exposure. Retention of the TLR7/8 agonist at the site of injection was demonstrated using quantitative whole-body autoradiography, HPLC-UV, and MALDI mass spectrometry imaging. Pharmacodynamic changes on T cells from TLR7/8 agonist treated B16-OVA tumors was assessed by histology, quantitative real time PCR, and flow cytometry. Combination activity of TLR7/8 agonism with immunotherapies was assessed in vitro by human DC-T cell MLR assay, and in vivo using multiple syngeneic mouse tumor models.ResultsTargeting both TLR7 and 8 triggers an innate and adaptive immune response in primary human immune cells, exemplified by secretion of IFNα, IL-12 and IFNγ. In contrast, a STING or a TLR9 agonist primarily induces release of IFNα. We demonstrate that the TLR7/8 agonist, MEDI9197, is retained at the sight of injection with limited systemic exposure. This localized TLR7/8 agonism leads to Th1 polarization, enrichment and activation of natural killer (NK) and CD8+ T cells, and inhibition of tumor growth in multiple syngeneic models. The anti-tumor activity of this TLR7/8 agonist is enhanced when combined with T cell-targeted immunotherapies in pre-clinical models.ConclusionLocalized TLR7/8 agonism can enhance recruitment and activation of immune cells in tumors and polarize anti-tumor immunity towards a Th1 response. Moreover, we demonstrate that the anti-tumor effects of this TLR7/8 agonist can be enhanced through combination with checkpoint inhibitors and co-stimulatory agonists.

Dataset Information

Adoptive immunotherapy combined with intratumoral TLR agonist delivery eradicates established melanoma in mice.

Publications

Adoptive immunotherapy combined with intratumoral TLR agonist delivery eradicates established melanoma in mice.

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