The Ly-49 family: genes, proteins and recognition of class I MHC.
The Ly-49 family consists of at least nine members, of which Ly-49A and C have been found to be NK-cell inhibitory receptors specific for class I MHC. The functions of other Ly-49 molecules are still unclear. Further analysis of Ly-49 is complicated by the cross-reactivities of some anti-Ly-49 antibodies initially thought to be specific for individual Ly-49 molecules. Studies on the role of Ly-49 in hybrid resistance as well as on allelic exclusion are also complicated by our recent finding that a novel Ly-49CB6 gene is the likely allelic form of Ly-49CBALB as opposed to a previously reported highly related but distinct gene in B6 mice. In cell-cell binding assays, only Ly-49A and C show significant binding to class I MHC. Ly-49A and C also bind some polysaccharides, and carbohydrates on class I MHC seem to be important for its binding to Ly-49. However, this interaction involves not only the carbohydrate recognition domain of Ly-49 but also a part of the stalk region, suggesting that both carbohydrates and peptide backbone of class I MHC may be recognized by Ly-49. It is likely that additional Ly-49 molecules yet to be identified function as NK-inhibitory receptors specific for class I MHC.
Takei
F
F
Terry Fox Laboratory, British Columbia Cancer Agency, University of British Columbia, Vancouver, Canada. fumio@terryfox.ubc.ca
Brennan
J
J
Mager
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DL
D000818:Animals; D000950:Antigens, Ly; D005805:Genes, MHC Class I / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000235:genetics* / Q000276:immunology*; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins / Q000235:genetics*; D005810:Multigene Family / Q000276:immunology*; D055630:Receptors, NK Cell Lectin-Like
D000950:Antigens, Ly; D015395:Histocompatibility Antigens Class I; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D055630:Receptors, NK Cell Lectin-Like