Natural killer cells: walking three paths down memory lane

Trends Immunol. 2013 Jun;34(6):251-8. doi: 10.1016/ Epub 2013 Mar 14.


Immunological memory has traditionally been regarded as a unique feature of the adaptive immune response, mediated in an antigen-specific manner by T and B lymphocytes. All other hematopoietic cells, including natural killer (NK) cells, are classified as innate immune cells, which have been considered short-lived but can respond rapidly against pathogens in a manner not thought to be driven by antigen. Interestingly, NK cells have recently been shown to survive long term after antigen exposure and subsequently mediate antigen-specific recall responses. In this review, we address the similarities between, and the controversies surrounding, three major viewpoints of NK memory that have arisen from these recent studies: (i) mouse cytomegalovirus (MCMV)-induced memory; (ii) cytokine-induced memory; and (iii) liver-restricted memory cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Antigens, Viral / immunology
  • Cell Differentiation / immunology
  • Cell Survival / immunology
  • Cytokines / immunology
  • Cytomegalovirus Infections / immunology*
  • Humans
  • Immunologic Memory*
  • Killer Cells, Natural / immunology*
  • Liver / immunology*
  • Lymphocyte Activation
  • Mice


  • Antigens, Viral
  • Cytokines