Role of human natural killer cells during Epstein-Barr virus infection

Human natural killer (NK) cells have been suggested to restrict viral infections. However, the evidence for this notion is mostly circumstantial. Recent studies in mice with reconstituted human immune system components, children with symptomatic primary Epstein-Barr virus (EBV) infection, and in secondary lymphoid tissues of healthy EBV carriers have, however, shown that early differentiated human NK cells limit lytic EBV replication and thereby prevent the immunopathological expansion of lytic EBV antigen specific CD8+ T cells that is known as infectious mononucleosis (IM). These findings, which will be discussed in this review, might offer the opportunity to identify EBV negative adolescents at risk to develop IM, and also more generally provide a good example to document restriction of a viral infection by human NK cells.