【项目简介】
Leukocyte immunoglobulinlike receptor subfamily B (LILRB3), also known as ILT5, LIR3, and CD85a, is an immunoglobulin superfamily member that is involved in immune regulation. Subfamily B members have cytoplasmic immunoreceptor tyrosinebased inhibitory motifs (ITIMs) that inhibit signaling events via phosphatase SHP1.Subfamily A members are activating receptors that lack ITIMs and signal through association with FcRγ . Mature LILRB3 is a highly polymorphic 8595 kDa glycoprotein that consists of a 420 amino acid (aa) extracellular domain (ECD) with four Iglike domains, a 21 aa transmembrane segment, and a 167 aa cytoplasmic domain with three ITIMs . Alternative splicing generates an isoform with a 17 aa insertion in the juxtamembrane ECD. In mouse and rat, the LILRB3 gene encodes the PIRB protein which has six Iglike domains. Rodent PIRB and human LILRB3 share 55% aa sequence identity within common regions of their ECDs. LILRB3 is expressed on the surface of peripheral monocytes, neutrophils, eosinophils, basophils, and mast cell progenitors (46). Triggering of LILRB3 inhibits the activation of macrophages, mast cells, neutrophils, basophils, and B cells. 

【检验原理】
本试剂盒采用双抗体夹心ELISA法。酶标微孔板上预包被有抗人LILRB3抗体，当加入标准品和待测样本时，标准品和待测样本中的人LILRB3会和该抗体结合。洗板后，游离的其他成分被洗去，加入辣根过氧化物酶标记的的抗人LILRB3抗体可与被酶标板捕获的人LILRB3结合，形成“包被抗人LILRB3抗体+人LILRB3+抗人LILRB3抗体-HRP”免疫复合物。当加入TMB显色底物后，复合物上连接的HRP催化底物反应，生成蓝色产物，终止反应后变为黄色。在450nm处测定OD值，人LILRB3浓度与OD450值之间呈正比，可通过绘制标准曲线求出标本中人LILRB3的浓度。