Global InformationLy49 information
Ly49 is a family of membrane C-type lectin-like receptors expressed mainly on NK cells but also on other immune cells (some CD8+ and CD3+ T lymphocytes, intestinal epithelial lymphocytes (IELs), NKT cells, uterine NK cells (uNK) cells, macrophages or dendritic cells).[1] Their primary role is to bind MHC-I molecules to distinguish between self healthy cells and infected or altered cells. Ly49 family is coded by Klra gene cluster and include genes for both inhibitory and activating paired receptors, but most of them are inhibitory.[2] Inhibitory Ly49 receptors play a role in the recognition of self cells and thus maintain self-tolerance and prevent autoimmunity by suppressing NK cell activation.[1] On the other hand, activating receptors recognise ligands from cancer or viral infected cells (induced-self hypothesis) and are used when cells lack or have abnormal expression of MHC-I molecules (missing-self hypothesis), which activate cytokine production and cytotoxic activity of NK and immune cells.[3]
Ly49 receptors are expressed in some mammals including rodents, cattle, some primates but not in humans.[4] Only one human gene homologous to rodent Ly49 receptors is found in the human genome, KLRA1P (LY49L), however, it represents a non-functional pseudogene.[5] However killer cell immunoglobulin-like receptors (KIR) have the same function in humans. They have different molecular structure but recognise HLA class I molecules as ligands and include both inhibitory (mainly) and activating receptors.[3]
- ^ a b Rahim MM, Tu MM, Mahmoud AB, Wight A, Abou-Samra E, Lima PD, Makrigiannis AP (2014-04-02). "Ly49 receptors: innate and adaptive immune paradigms". Frontiers in Immunology. 5: 145. doi:10.3389/fimmu.2014.00145. PMC 3980100. PMID 24765094.
- ^ Schenkel AR, Kingry LC, Slayden RA (2013). "The ly49 gene family. A brief guide to the nomenclature, genetics, and role in intracellular infection". Frontiers in Immunology. 4: 90. doi:10.3389/fimmu.2013.00090. PMC 3627126. PMID 23596445.
- ^ a b Pegram HJ, Andrews DM, Smyth MJ, Darcy PK, Kershaw MH (February 2011). "Activating and inhibitory receptors of natural killer cells". Immunology and Cell Biology. 89 (2): 216–24. doi:10.1038/icb.2010.78. PMID 20567250. S2CID 205150594.
- ^ Rahim MM, Makrigiannis AP (September 2015). "Ly49 receptors: evolution, genetic diversity, and impact on immunity". Immunological Reviews. 267 (1): 137–47. doi:10.1111/imr.12318. PMID 26284475. S2CID 13458485.
- ^ Westgaard IH, Berg SF, Orstavik S, Fossum S, Dissen E (June 1998). "Identification of a human member of the Ly-49 multigene family". European Journal of Immunology. 28 (6): 1839–46. doi:10.1002/(SICI)1521-4141(199806)28:06<1839::AID-IMMU1839>3.0.CO;2-E. PMID 9645365. S2CID 43688770.