Blockade of Tim-3 binding to phosphatidylserine and CEACAM1 is a shared feature of anti-Tim-3 antibodies that have functional efficacy.

Both data in preclinical cancer models and data with T cells from patients with advanced cancer support a role for Tim-3 blockade in promoting effective anti-tumor immunity. Consequently, there is considerable interest in the clinical development of antibody-based therapeutics that target Tim-3 for cancer immunotherapy. A challenge to this clinical development is the fact that several ligands for Tim-3 have been identified: galectin-9, phosphatidylserine, HMGB1, and most recently, CEACAM1.

TIGIT predominantly regulates the immune response via regulatory T cells.

Coinhibitory receptors are critical for the maintenance of immune homeostasis. Upregulation of these receptors on effector T cells terminates T cell responses, while their expression on Tregs promotes their suppressor function. Understanding the function of coinhibitory receptors in effector T cells and Tregs is crucial, as therapies that target coinhibitory receptors are currently at the forefront of treatment strategies for cancer and other chronic diseases.

A T cell extrinsic mechanism by which IL-2 dampens Th17 differentiation.

Genetic variants in il2 and il2ra have been associated with autoimmune disease susceptibility in both genome-wide association studies (GWAS) in humans and in genetic linkage studies in experimental models of autoimmunity. Specifically, genetic variants resulting in a low IL-2 phenotype are susceptibility alleles while variants resulting in a high IL-2 phenotype are resistance alleles. The association of high IL-2 phenotypes with resistance has been attributed primarily to the T cell intrinsic promotion of regulatory T cell development, maintenance, and function; however, IL-2 can also act T cell intrinsically to dampen differentiation of pathogenic IL-17-producing Th17 cells.

An IL-27/NFIL3 signalling axis drives Tim-3 and IL-10 expression and T-cell dysfunction.

The inhibitory receptor T-cell immunoglobulin and mucin domain-3 (Tim-3) has emerged as a critical regulator of the T-cell dysfunction that develops in chronic viral infections and cancers. However, little is known regarding the signalling pathways that drive Tim-3 expression. Here, we demonstrate that interleukin (IL)-27 induces nuclear factor, interleukin 3 regulated (NFIL3), which promotes permissive chromatin remodelling of the Tim-3 locus and induces Tim-3 expression together with the immunosuppressive cytokine IL-10.