NKR-P1A is a target-specific receptor that activates natural killer cell cytotoxicity

J Exp Med. 1995 May 1;181(5):1911-5. doi: 10.1084/jem.181.5.1911.


NKR-P1A is a lectinlike surface molecule expressed on rat natural killer (NK) cells. NKR-P1A has structural and functional features of an activating NK cell receptor, but a requirement for NKR-P1A in target cell lysis has not been determined. To define the role of NKR-P1A in natural killing, we have generated a mutant of the rat NK cell line, RNK-16, lacking expression of all members of the NKR-P1 receptor family. Although these NKR-P1-deficient NK cells were able to kill many standard tumor targets, including YAC-1, they were selectively deficient in the lysis of IC-21 macrophage, B-16 melanoma, and C1498 lymphoma targets. Reexpression of a single member of the NKR-P1 family, NKR-P1A, on mutant cells restored lysis of IC-21, and killing of IC-21 targets through rat NKR-P1A was completely blocked by F(ab')2 anti-NKR-P1A. Reexpression of NKR-P1A also restored transmembrane signaling to IC-21, as assessed by the generation of inositol-1,4,5-trisphosphate. The generation of inositol-1,4,5-trisphosphate was also restored in response to B-16 targets, but both B-16 and C1498 cells remained resistant to lysis, indicating that other NK cell molecules, perhaps within the NKR-P1 family, are required for the efficient killing of these tumors. These results are the first to demonstrate that NKR-P1A is a target-specific receptor that activates natural killing.

Publication types

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

MeSH terms

  • Animals
  • Antigens, Surface / physiology*
  • Cytotoxicity, Immunologic
  • Killer Cells, Natural / immunology*
  • Lectins, C-Type*
  • NK Cell Lectin-Like Receptor Subfamily B
  • Rats
  • Rats, Inbred F344
  • Receptors, Immunologic / physiology*
  • Tumor Cells, Cultured


  • Antigens, Surface
  • Lectins, C-Type
  • NK Cell Lectin-Like Receptor Subfamily B
  • Receptors, Immunologic