【项目简介】
IL-28A，IL-28B，and IL-29，also named interferon-lambda 2 (IFN-lambda 2)，IFN-lambda 3，and IFN-lambda 1， respectively，are class II cytokine receptor ligands that are distantly related to members of the IL-10 family (11-13% aa sequence identity) and type I IFN family (15-19% aa sequence identity) (1-3)。The three proteins signal through the same heterodimeric receptor complex that is composed of the IL-10 receptor  beta (IL-10 R beta ) and a novel IL-28 receptor alpha (IL-28 R alpha, also known as IFN-lambda R1)。Ligand binding to the receptor complex induces Jak kinase activation and STAT1 and STAT2 tyrosine phosphorylation. Human IL-28A cDNA encodes a 200 amino acid (aa) residue precursor protein with a putative 25 aa signal peptide。It shares 94% and 67% aa sequence identity with human IL-28B and human IL-29，respectively。

【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IL-28抗体，当加入标准品和待测样本时，重组或天然的人IL-28会和该抗体结合。洗板后，游离的其他成分被洗去，加入生物素化的抗人IL-28抗体可与被酶标板捕获的人IL-28结合。再次洗板后，游离的其他成分被洗去，加入辣根过氧化物酶标记的链霉亲和素，生物素和链霉亲和素特异性结合，形成“包被抗人IL-28抗体+人IL-28+生物素化抗人IL-28抗体+链霉亲和素-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IL-28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IL-28的浓度。