B3GAT1 and viral infectious disease: CD57 is associated with more experienced and terminally differentiated NK cells, possibly on the verge of senescence186 with higher frequency in older age.187 CD57 is also a marker of senescent T-cells that have short telomeres and low replication potential.188,189 NK3 population might specialize in highly effective and adaptive properties with memory-like features if they encounter an event such as viral infection.