Ligands for natural killer cell receptors: redundancy or specificity

Authors

  • Adelheid Cerwenka,

    1. Department of Microbiology and Immunology and the Cancer Research Institute, University of California, San Francisco, San Francisco, California, USA
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  • Lewis L. Lanier

    Corresponding author
    1. Department of Microbiology and Immunology and the Cancer Research Institute, University of California, San Francisco, San Francisco, California, USA
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Correspondence to: Lewis L. Lanier
Department of Microbiology and Immunology and the Cancer Research Institute
University of California, San Francisco
513, Parnassus Ave.
HSE 420
Box 0414
San Francisco, CA 94143-0414
USA
Fax: 1 415 476 0939
e-mail: lanier@itsa.ucsf.edu

Abstract

Summary: Several inhibitory and activating receptors involved in natural killer cell activation have been characterized. The increasing knowledge about their ligands, including classical MHC class I molecules, non-classical MHC class I molecules and MHC class I-related molecules, is shedding new light on the targets of innate immune recognition. While classical MHC class I molecules are constitutively expressed, some MHC class I-related (MIC) molecules, however, are stress-induced by ill-defined stimuli. Two families of ligands for the human activating NKG2D receptor have been identified. These are the MIC proteins encoded by two highly polymorphic genes within the MHC class I and the retinoic acid-inducible early gene-1-like (also designated UL16-binding) proteins encoded by genes outside the MHC. For the mouse NKG2D receptor, one family, containing at least five distinct ligands, has been described. A better understanding about how targets signal their distress, which renders them susceptible to natural killer (NK)-cell attack, will help to define the role of NK cells in antimicrobial and antitumor immunity and transplantation.

Supported by NIH grants CA89294 and CA89189

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