Differential IL-12 signaling induces human natural killer cell activating receptor-mediated ligand-specific expansion

J Exp Med. 2022 Aug 1;219(8):e20212434. doi: 10.1084/jem.20212434. Epub 2022 Jun 27.


IL-12 is an essential cytokine involved in the generation of memory or memory-like NK cells. Mouse cytomegalovirus infection triggers NK receptor-induced, ligand-specific IL-12-dependent NK cell expansion, yet specific IL-12 stimulation ex vivo leading to NK cell proliferation and expansion is not established. Here, we show that IL-12 alone can sustain human primary NK cell survival without providing IL-2 or IL-15 but was insufficient to promote human NK cell proliferation. IL-12 signaling analysis revealed STAT5 phosphorylation and weak mTOR activation, which was enhanced by activating NK receptor upregulation and crosslinking leading to STAT5-dependent, rapamycin-sensitive, or TGFβ-sensitive NK cell IL-12-dependent expansion, independently of IL-12 receptor upregulation. Prolonged IL-2 culture did not impair IL-12-dependent ligand-specific NK cell expansion. These findings demonstrate that activating NK receptor stimulation promotes differential IL-12 signaling, leading to human NK cell expansion, and suggest adopting strategies to provide IL-12 signaling in vivo for ligand-specific IL-2-primed NK cell-based therapies.

Publication types

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

MeSH terms

  • Cell Proliferation
  • Humans
  • Interleukin-12*
  • Interleukin-2 / pharmacology
  • Ligands
  • Receptors, Natural Killer Cell
  • STAT5 Transcription Factor*


  • Interleukin-2
  • Ligands
  • Receptors, Natural Killer Cell
  • STAT5 Transcription Factor
  • Interleukin-12