Defined TLR3-specific adjuvant that induces NK and CTL activation without significant cytokine production in vivo.

Misako Matsumoto,Akiko Morii-Sakai,Fumiko Nishikawa,Megumi Tatematsu,Noriko Ishii,Masahiro Azuma,Tsukasa Seya,Hiroaki Shime

doi:10.1038/ncomms7280

Misako Matsumoto, Akiko Morii-Sakai + Show 6 more

Open Access

https://doi.org/10.1038/ncomms7280

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Journal: Nature communications	Publication Date: Feb 18, 2015
Citations: 111	License type: cc-by

Affiliation: Hokkaido University

Abstract

Ligand stimulation of the Toll-like receptors (TLRs) triggers innate immune response, cytokine production and cellular immune activation in dendritic cells. However, most TLR ligands are microbial constituents, which cause inflammation and toxicity. Toxic response could be reduced for secure immunotherapy through the use of chemically synthesized ligands with defined functions. Here we create an RNA ligand for TLR3 with no ability to activate the RIG-I/MDA5 pathway. This TLR3 ligand is a chimeric molecule consisting of phosphorothioate ODN-guided dsRNA (sODN-dsRNA), which elicits far less cytokine production than poly(I:C) in vitro and in vivo. The activation of TLR3/TICAM-1 pathway by sODN-dsRNA effectively induces natural killer and cytotoxic T cells in tumour-loaded mice, thereby establishing antitumour immunity. Systemic cytokinemia does not occur following subcutaneous or even intraperitoneal administration of sODN-dsRNA, indicating that TICAM-1 signalling with minute local cytokines sufficiently activate dendritic cells to prime tumoricidal effectors in vivo.

Highlights

Ligand stimulation of the Toll-like receptors (TLRs) triggers innate immune response, cytokine production and cellular immune activation in dendritic cells
Because 440 bp dsRNA may be the minimal length for activation of TLR3, we selected the region of defective interference RNA in the vaccine measles virus (MV) that causes no RNA interference[25]
When the compounds were transfected into cytoplasm with Lipofectamine, mitochondrial antiviral-signalling protein (MAVS)-dependent cytokine production was barely observed with cM362-140, whereas only low levels of IL-6 and IFN-b were induced with cM362-139 in TLR3 KO dendritic cell (DC) (Fig. 2b, right panel). This MAVS activity may reflect the exposure of a few 50-triphosphated species of cM362-139(IVT) due to minor RNA degradation. These results indicate that cM362-140 targets endosomal TLR3 and activate the Toll-IL-1 receptor domain-containing adaptor molecule (TICAM)-1 pathway in both human and mouse cells

Summary

Introduction

Ligand stimulation of the Toll-like receptors (TLRs) triggers innate immune response, cytokine production and cellular immune activation in dendritic cells. Type I IFN and DC-mediated immune responses are evoked to suppress virus replication These responses occur in a complex manner, what happens in vivo when only a single receptor is stimulated remains to be elucidated, whereas what happens in vivo when a single gene is disrupted has been reported in knockout (KO) mouse studies[1]. We generated synthetic dsRNA derivatives expected to act on TLR3, but not on RIG-I/MDA5 These ligands exhibited strong activity in inducing antitumour CTL and NK cells and caused marked regression of tumours without off-target effects including significant increases of serum cytokine/IFN levels in mouse models

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