The role of CD94/NKG2 in innate and adaptive immunity

Immunol Res. 2004;30(1):29-34. doi: 10.1385/IR:30:1:029.

Abstract

CD94/NKG2 is a heterodimer expressed on natural killer (NK) and a small subset of T cells. This receptor varies in function as an inhibitor or activator depending on which isoform of NKG2 is expressed. The ligand for CD94/NKG2 is HLA-E in human and its homolog, Qa1 in mouse, which are both nonclassical class I molecules that bind leader peptides from other class I molecules. Although <5% of CD8 T cells express the receptor in a naïve mouse, its expression is upregulated upon specific recognition of antigen. Similar to NK cells, most CD8 T cells that express high levels of CD94 co-express NKG2A, the inhibitory isoform. The engagement of this receptor can lead to a blocking of cytotoxicity. However, these receptors have also been implicated in the cell survival of both NK and CD8 T cells. The level of CD94 expression is inversely correlated with the level of apoptosis in culture. Thus, CD94/NKG2 receptors may regulate effector functions and cell survival of NK cells and CD8 T cells, thereby playing a crucial role in the innate and adaptive immune response to a pathogen.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Antigens, CD / immunology*
  • Apoptosis / immunology
  • CD8-Positive T-Lymphocytes / immunology*
  • Cell Survival / immunology
  • Humans
  • Immunity, Cellular
  • Immunity, Innate
  • Killer Cells, Natural / immunology*
  • Lectins, C-Type / immunology*
  • NK Cell Lectin-Like Receptor Subfamily C
  • NK Cell Lectin-Like Receptor Subfamily D
  • Receptors, Immunologic / immunology*
  • Receptors, Natural Killer Cell

Substances

  • Antigens, CD
  • KLRC1 protein, human
  • KLRD1 protein, human
  • Klrc1 protein, mouse
  • Lectins, C-Type
  • NK Cell Lectin-Like Receptor Subfamily C
  • NK Cell Lectin-Like Receptor Subfamily D
  • Receptors, Immunologic
  • Receptors, Natural Killer Cell