title: Adaptive immune features of natural killer cells.
abstract: In an adaptive immune response, naive T cells proliferate during infection and generate long-lived memory cells that undergo secondary expansion after a repeat encounter with the same pathogen. Although natural killer (NK) cells have traditionally been classified as cells of the innate immune system, they share many similarities with cytotoxic T lymphocytes. We use a mouse model of cytomegalovirus infection to show that, like T cells, NK cells bearing the virus-specific Ly49H receptor proliferate 100-fold in the spleen and 1,000-fold in the liver after infection. After a contraction phase, Ly49H-positive NK cells reside in lymphoid and non-lymphoid organs for several months. These self-renewing 'memory' NK cells rapidly degranulate and produce cytokines on reactivation. Adoptive transfer of these NK cells into naive animals followed by viral challenge results in a robust secondary expansion and protective immunity. These findings reveal properties of NK cells that were previously attributed only to cells of the adaptive immune system.
authors.affiliation: Department of Microbiology and Immunology and the Cancer Research Institute, University of California, San Francisco, California 94143, USA.
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Sun
authors.forename: Joshua N
authors.initials: JN
authors.lastname: Beilke
authors.forename: Lewis L
authors.initials: LL
authors.lastname: Lanier
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000172:deficiency / Q000235:genetics; D019264:Adoptive Transfer; D000818:Animals; D049109:Cell Proliferation; D007156:Immunologic Memory / Q000276:immunology*; D007694:Killer Cells, Natural / Q000166:cytology* / Q000276:immunology*; D008221:Lymphoid Tissue / Q000276:immunology; D051379:Mice; D020297:Mice, Congenic; D008810:Mice, Inbred C57BL; D018448:Models, Immunological; D018146:Muromegalovirus / Q000276:immunology / Q000502:physiology; D010641:Phenotype; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C484963:Tyrobp protein, mouse