T-cell immunoreceptor with Ig and ITIM domains (TIGIT), also known as VSIG9, VSTM3, WUCAM, V-set is an immune checkpoint, offering potential as an immunotherapeutic target. This transmembrane glycoprotein receptor, featuring an Ig-like V-type and an ITIM in its cytoplasmic region, is expressed on activated and memory T cells, NK cells, and Tregs. Immune checkpoints, known as co-inhibitory receptors, are vital for regulating immune cell function to maintain tolerance and prevent autoimmunity. Established checkpoints like PD-1 and CTLA-4 play significant roles in autoimmune diseases and cancer, with their blockade already approved for cancer therapy. Given the suppressive microenvironments of tumors with elevated immune checkpoints on tumor-infiltrating lymphocytes, targeting TIGIT and similar receptors holds promise for advancing cancer treatment.

Abbreviations: 

V-set and transmembrane domain-containing protein 3, V-set and immunoglobulin domain-containing protein 9, WUCAM, VSIG9, VSTM3