UC‐1V150, a potent TLR7 agonist capable of activating macrophages and potentiating mAb‐mediated target cell deletion

Abstract

Toll-like receptors (TLR) are critical mediators of the immune system with their activation linked to infection, inflammation and the pathogenesis of immune diseases including autoimmunity and cancer. For this reason, over the last 2 decades, TLR and their associated signalling pathways have been targeted therapeutically to enhance innate and adaptive immunity. Several TLR ligands, both endogenous and synthetic are at various phases of clinical testing, and new ligands are continually emerging. Agonists of TLR7 are known immune response modifiers, simultaneously stimulating several cell types, resulting in immune cell activation and cytokine and chemokine release. The immune stimulating properties of the TLR7 agonist Imiquimod has also been exploited for use in the treatment of malignant superficial tumours of the skin. Here, we investigated a novel TLR7 agonist UC-1V150 and demonstrate it activates both human and mouse myeloid cells in vitro and in vivo, to deliver potent FcγR-mediated engulfment of opsonized target cells.

Molecular Repolarisation of Tumour-Associated Macrophages

“…A few examples have been depicted in Figure 3. [67,68,69,70]. Furthermore, combination of TLR ligands into multivalent conjugates could lead to synergistic effects and phenotypically distinct polarisation states [71,72].…”

Improved Multiplex Immunohistochemistry for Immune Microenvironment Evaluation of Mouse Formalin-Fixed, Paraffin-Embedded Tissues

“…Using knowledge from the literature and considering the available antibodies for mouse targets, we stained for CD163 and Fcgr4. According to ImmGen (Figure 1, 20) and previous reports (16, 17), Fcgr4 is expressed by macrophages and neutrophils. This is corroborated by flow cytometric analysis (Figure 3G).…”

“…Applying our revised protocol to test over 35 primary antibodies specific for mouse immune subsets, we developed a panel of lymphoid and myeloid cell markers (Table 1). These markers were chosen based on ImmGEN expression data (Figure 1, 20), previous reports (16, 17, 21–24), and antibody availability. Using chromagen and fluorescence (via tyramide signal amplification) detection methods, we observed that each marker produced expected staining patterns corresponding with known localization and expression by the respective cell types of interest (Supplemental Figures 4, 25).…”

“…Single cell suspensions were prepared from C57BL/6 mouse spleens. 1×10 6 cells were stained with CD11b PE, Ly6C PerCP-Cy5.5, Ly6G PE-Cy7 (eBioscience), F4/80 APC (AbD Serotec) and FcγR antibodies as previously described (16, 17). Data were acquired on the FACS Canto II (BD Biosciences) and analyzed with FCS express (DeNovo Software).…”

Bringing Macrophages to the Frontline against Cancer: Current Immunotherapies Targeting Macrophages

“…Treated tumors accumulated antitumor TAMs, which killed tumor cells directly through the production of NO and were essential for the antitumor activity [ 248 ]. In addition, TLR7/8 agonists reprogramed protumoral TAMs into antitumoral effectors in mouse models of melanoma (B16) and colon cancer (MC38) [ 249 ] and TAMs become very efficient at antibody-mediated phagocytosis [ 250 , 251 ]. Thus, TLR7/8 agonists are considered valuable additional reagents with great potential in combinations with ICB and vaccination and are intensely being investigated.…”