Biology subjects

Sun, Y.-F.

Publications and source records attributed to Sun, Y.-F..

2 recordsLinked to original sources

bioRxiv2022

Galectin-8 is a major ligand of LILRB4 prompting MDSC functions in the tumor microenvironment

The LILRB4 myeloid receptor has been implicated in an immunosuppressive microenvironment, with specific antibodies under preclinical or clinical development for tumor immunotherapy. However, it remains largely unknown which natural ligand may trigger LILRB4 to expand myeloid derived suppressive cells (MDSC), and the relevant downstream signaling pathways are also under debate. Here we show that Galectin-8 is a high-affinity functional ligand of LILRB4, and its ligation induces MDSC by activating STAT3 as well as inhibiting NF-{kappa}B. Importantly, Galectin-8 but not APOE could induce MDSC, and both ligands bind LILRB4 in a non-competitive manner. Antibodies recognizing a defined epitope on LILRB4 could efficiently block Galectin-8 binding and neutralize its effects on MDSC induction and relevant signaling pathways. Galectin-8 expression promoted B16 tumor growth in mice, and knockout of LILRB4 attenuated tumor growth in this context. The LILRB4-specific Galectin-8 blocking antibody efficiently suppressed MDSC expansion and tumor growth in vivo. These results identify Galectin-8 as a functionally important ligand of LILRB4, highlighting the blockade of LILRB4-Galectin-8 interaction as a promising strategy for cancer immunotherapy.

immunology↗

bioRxiv2022

The ITPRIPL1- CD3ϵ axis: a novel immune checkpoint controlling T cells activation

The immune system is critical to fighting infections and disease. The molecular recognition of harmful entities takes place when antigen-presenting cells (APC) harboring major histocompatibility complex (MHC) molecules bound to peptides derived from harmful antigens (ligand) dock on specific T cell receptor (TCR)-CD3 complex (receptor) at the surface of CD8+ T cells. The discovery of a general immune checkpoint mechanism to avoid the harmful impact of T cell hyperactivation provoked a paradigm shift. The clinical relevance of this mechanism is highlighted by the fact that PD-1 and PD-L1 inhibitors are very effective at boosting immune reactions. Still, immune evasion frequently happens. The observation that some PD-1/PD-L1 negative tumors have a poor immune response opens the door to identifying a novel immune checkpoint mechanism. Here, we discovered that ITPRIPL1, a gene with unknown function, impairs T cell activation. Surprisingly, we found that CD3{varepsilon} is the direct receptor of ITPRIPL1. This novel immune checkpoint was validated as a drug target using ITPRIPL1 KO mice and monoclonal antibodies. Thus, targeting the ITPRIPL1-CD3e axis, especially in PD-1 - PDL-1 negative patients, is a promising therapeutic strategy to reduce immune evasion.

immunology↗