Cutting edge: NKG2C(hi)CD57+ NK cells respond specifically to acute infection with cytomegalovirus and not Epstein-Barr virus.

CMV induces the expansion of a unique subset of human NK cells expressing high levels of the activating CD94-NKG2C receptor that persist after control of the infection. We investigated whether this subset is CMV specific or is also responsive to acute infection with EBV. We describe a longitudinal study of CMV(-) and CMV(+) students who were acutely infected with EBV. The NKG2C(hi) NK subset was not expanded by EBV infection. However, EBV infection caused a decrease in the absolute number of immature CD56(bright)CD16(-) NK cells in the blood and, in CMV(+) individuals, induced an increased frequency of mature CD56(dim)NKG2A(+)CD57(+) NK cells in the blood that persisted into latency. These results provide further evidence that NKG2C(+) NK cells are CMV specific and suggest that EBV infection alters the repertoire of NK cells in the blood.