Natural killer cell receptors in the horse: Evidence for the existence of multiple transcribed LY49 genes

Tomoko Takahashi, Makoto Yamata, Terje Raudsepp, Teri L. Lear, Bhanu P. Chowdhary, Douglas F. Antczak, Masanori Kasahara

Research output: Contribution to journalArticlepeer-review

53 Citations (Scopus)


In rodents, the Ly49 family encodes natural killer (NK) receptors interacting with classical MHC class I molecules, whereas the corresponding receptors in primates are members of the killer cell immunoglobulin-like receptor (KIR) family. Recent evidence indicates that the cattle, domestic cat, dog, and pig have a single LY49 and multiple KIR genes, suggesting that predominant NK receptors in most non-rodent mammals might be KIR. Here, we show that the horse has at least six LY49 genes, five with an immunoreceptor tyrosine-based inhibition motif (ITIM) and one with arginine in the transmembrane region. Interestingly, none of the horse KIR-like cDNA clones isolated by library screening encoded molecules likely to function as NK receptors; four types of clones were KIR-Ig-like transcript (KIR-ILT) hybrids and contained premature stop codons and/or frameshift mutations, and two putative allelic sequences predicting KIR3DL molecules had mutated ITIM. To our knowledge, this is the first report suggesting that non-rodent mammals may use LY49 as NK receptors for classical MHC class I. We also show that horse spleen expresses ILT-like genes with unique domain organizations. Radiation hybrid mapping and fluorescence in situ hybridization localized horse LY49 and KIR/ILT genes to chromosomes 6q13 and 10p12, respectively.

Original languageEnglish
Pages (from-to)773-784
Number of pages12
JournalEuropean Journal of Immunology
Issue number3
Publication statusPublished - Mar 2004
Externally publishedYes


  • Evolution
  • Horse
  • KIR
  • LY49
  • NK receptor

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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