A novel tumor-targeted interferon-α/-β receptor 1 antagonist increases replication of oncolytic vesicular stomatitis virus in a mouse mesothelioma model

Type I Interferons (IFN-I) are cytokines with pleiotropic activities involved in antiviral and antitumor immune responses. They can reduce oncolytic virus replication in tumor cells by inducing expression of interferon stimulated genes (ISG) with antiviral functions. To specifically neutralize the IFN-/-{beta} receptor (IFNAR) on specific cell types, we created novel IFNAR1-targeted antagonists constituted of a high-affinity nanobody targeting a specific cell surface marker conjugated to a low-affinity blocking nanobody targeting IFNAR1. We first show in vitro and in vivo that such an antagonist targeting the mouse CD20 molecule (mCD20) inhibits IFNAR signaling only in B cells among splenocytes. We then showed in vitro that a human CD20 (hCD20)-targeted antagonist blocks IFNAR signaling and induces vesicular stomatitis virus (VSV) oncolytic activity against IFN-11-treated AK7 mesothelioma or B16 melanoma cells only if these cells express hCD20. In vivo, we show that the antagonist binds to hCD20 and enhances VSV replication by inhibiting ISG expression specifically in hCD20+ AK7 mesothelioma tumors. Altogether our results demonstrate the efficient and cell-type specific inhibition of IFNAR signaling through the use of these novel IFNAR1 antagonists, both in vitro and in vivo. These antagonists could have many therapeutic applications given the importance of IFN-I in numerous diseases. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=124 SRC="FIGDIR/small/729496v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@4e76b6org.highwire.dtl.DTLVardef@153c39borg.highwire.dtl.DTLVardef@4f0948org.highwire.dtl.DTLVardef@ea8d85_HPS_FORMAT_FIGEXP M_FIG C_FIG eTOC synopsisIn this study, we created cell-specific IFNAR antagonists that allow to inhibit selectively IFNAR signaling in particular types of cell. We show that this antagonist can be used to target IFNAR at the surface of tumor cells that lead to the inhibition of IFNAR signaling and ISG expression in these cells rendering them more permissive to VSV replication. Beside antitumor virotherapy, these novel antagonist could be useful to study role of IFN-I in normal or pathological context.