3-beta-glucuronosyltransferase 1 (B3GAT1) is an enzyme that in humans is encoded by the B3GAT1gene, whose enzymatic activity creates the CD57 epitope on other cell surface proteins.[5] In immunology, the CD57 antigen (CD stands for cluster of differentiation) is also known as HNK1 (human natural killer-1) or LEU7. It is expressed as a carbohydrate epitope that contains a sulfoglucuronyl residue in several adhesion molecules of the nervous system.[6]
Function
The protein encoded by this gene is a member of the glucuronyltransferase gene family. These enzymes exhibit strict acceptor specificity, recognizing nonreducing terminal sugars and their anomeric linkages. This gene product functions as the key enzyme in a glucuronyl transfer reaction during the biosynthesis of the carbohydrate epitope HNK-1 (human natural killer-1, also known as CD57 and LEU7). Alternate transcriptional splice variants have been characterized.[5]
There is an increase in the number of circulating CD57 positive cells in the blood of patients who have recently undergone organ or tissue transplants, especially of the bone marrow, and in patients with HIV. Increased CD57+ counts have also been reported in rheumatoid arthritis and Felty's syndrome, among other conditions.[8] High levels of CD57 expression amongst circulating CD8+ T cells is associated with other markers of immune ageing (immunosenescence) and may be associated with increased cancer risk in renal transplant recipients.[9]
^Mitsumoto Y, Oka S, Sakuma H, Inazawa J, Kawasaki T (April 2000). "Cloning and chromosomal mapping of human glucuronyltransferase involved in biosynthesis of the HNK-1 carbohydrate epitope". Genomics. 65 (2): 166–173. doi:10.1006/geno.2000.6152. PMID10783264.
^Wick MR (2010). "Chapter 11 – Immunohistology of the Mediastinum". In Dabbs DJ (ed.). Diagnostic immunohistochemistry: theranostic and genomic applications (3rd ed.). Philadelphia, PA: Saunders/Elsevier. pp. 345–6. doi:10.1016/B978-1-4160-5766-6.00015-7. ISBN 978-1-4160-5766-6.
^ abcLeong AS, Cooper K, Leong FJ (2003). Manual of Diagnostic Antibodies for Immunohistology (2nd ed.). London: Greenwich Medical Media. pp. 131–134. ISBN 978-1-84110-100-2.
Mitsumoto Y, Oka S, Sakuma H, Inazawa J, Kawasaki T (April 2000). "Cloning and chromosomal mapping of human glucuronyltransferase involved in biosynthesis of the HNK-1 carbohydrate epitope". Genomics. 65 (2): 166–173. doi:10.1006/geno.2000.6152. PMID10783264.
Chochi K, Ichikura T, Majima T, Kawabata T, Matsumoto A, Sugasawa H, et al. (2004). "The increase of CD57+ T cells in the peripheral blood and their impaired immune functions in patients with advanced gastric cancer". Oncology Reports. 10 (5): 1443–1448. doi:10.3892/or.10.5.1443. PMID12883721.
Sada-Ovalle I, Torre-Bouscoulet L, Valdez-Vázquez R, Martínez-Cairo S, Zenteno E, Lascurain R (December 2006). "Characterization of a cytotoxic CD57+ T cell subset from patients with pulmonary tuberculosis". Clinical Immunology. 121 (3): 314–323. doi:10.1016/j.clim.2006.08.011. PMID17035093.
