Involved in intercellular adhesion, lymphocyte signaling, cytotoxicity and lymphokine secretion mediated by cytotoxic T-lymphocyte (CTL) and NK cell (PubMed:8673704). Cell surface receptor for NECTIN2. Upon ligand binding, stimulates T-cell proliferation and cytokine production, including that of IL2, IL5, IL10, IL13, and IFNG. Competes with PVRIG for NECTIN2-binding (PubMed:26755705). Interacts with PVR and NECTIN2. Competes with PVRIG for NECTIN2-binding. Expressed by peripheral blood T-lymphocytes.