This site is intended for
Healthcare Professionals only.

For Patients


KIR pathway expressed on NK cells diagram

Killer cell immunoglobulin-like receptor (KIR), an immune checkpoint receptor expressed on natural killer (NK) cells, may inhibit NK cells from destroying normal cells. Inhibition of KIR may enhance NK cell antitumor activity.

  • KIRs are inhibitory immune checkpoint receptors expressed on NK cells and cytotoxic T cells1,2
    • Nearly every normal cell expresses the ligand for inhibitory KIRs1
  • KIRs are key regulators of NK-cell cytotoxic activity1
    • When the ligand on the normal cell engages with the inhibitory KIR on the NK cell, the NK cell recognizes the cell as normal and does not destroy it1
  • In preclinical studies, blockade of inhibitory KIRs has been shown to help restore NK cell–mediated immune activity4,5
Thumbnail for the How Does KIR Modulate Innate Immunity? video Thumbnail for the How Does KIR Modulate Innate Immunity? video

How does KIR modulate innate immunity?

Learn more about KIR and NK cell activity

Watch video

Get I-O Resources

Order or download
educational tools for your
patients and practice

See all resources

Clinical Trials

Learn more about our
current clinical trials

Learn more


1. Campbell KS, Purdy AK. Structure/function of human killer cell immunoglobulin-like receptors: lessons from polymorphisms, evolution, crystal structures and mutations. Immunology. 2011;132(3):315-325. 2. Björkström NK, Béziat V, Cichocki F, et al. CD8 T cells express randomly selected KIRs with distinct specificities compared with NK cells. Blood. 2012;120(17):3455-3465. 3. Carbone E, Neri P, Mesuraca M, et al. HLA class I, NKG2D, and natural cytotoxicity receptors regulate multiple myeloma cell recognition by natural killer cells. Blood. 2005;105(1):251-258. 4. Waldhauer I, Steinle A. NK cells and cancer immunosurveillance. Oncogene. 2008;27(45):5932-5943. 5. Romagné F, André P, Spee A, et al. Preclinical characterization of 1-7F9, a novel human anti–KIR receptor therapeutic antibody that augments natural killer–mediated killing of tumor cells. Blood. 2009;114(13):2667-2677.