Plays a role in escape from host immune response. Blocks the interaction between the host KLRK1 receptor with the ligands ULBP1 and ULBP2. ULBPs activate multiple signaling pathways in primary NK cells, resulting in the production of cytokines and chemokines. The sequestration of diverse KLRK1 ligands in the endoplasmic reticulum and cis-Golgi apparatus of cells by UL16 inhibits the activation of NK cells. Interacts with host ULBP1, ULBP2 and MICB. Belongs to the HHV-5 UL16 protein family.