预期应用
ELISA法定量测定人血清、血浆、细胞培养物上清或其它相关液体中LIF含量。
实验原理
本试剂盒应用双抗体夹心酶标免疫分析法测定标本中LIF水平。用纯化的抗体包被微孔板，制成固相抗体，往包被单抗的微孔中依次加入LIF抗原、生物素化的抗人LIF抗体、HRP标记的亲和素，经过彻底洗涤后用底物TMB显色。TMB在过氧化物酶的催化下转化成蓝色，并在酸的作用下转化成最终的黄色。颜色的深浅和样品中的LIF呈正相关。用酶标仪在450nm波长下测定吸光度（OD值），计算样品浓度。
Intended use
This immunoassay kit allows for the specific measurement of human LIF concentrations in cell culture supernates, serum, and plasma.
Introduction
Leukemia Inhibitory Factor (or LIF) is a variably glycosylated, 38 - 67 kDa polypeptide originally
identified as a proliferation inhibitor and differentiation inducer of the mouse M1 myeloid leukemia cell line. The mature LIF molecule measures 180 amino acid (aa) residues in length, with multiple potential N-linked and O-linked glycosylation sites plus six conserved cysteines that form three intramolecular disulfide bridges. Mature mouse LIF is 78% identical to human LIF at the aa sequence level. Although such homology might suggest a high conservation of LIF biology, notable differences exist between the reported forms of mouse and human LIF proteins and their receptors. For example, alternative splice events are known to occur in mice, but not humans, creating two isoforms of secreted LIF. Also, three isoforms of the LIF receptor a-chain, two soluble forms and one transmembrane form, have been reported in mice, but not in humans. Based on its helical structure, LIF is considered to be a member of the Interleukin-6 family of cytokines. Cells known to express LIF include activated T-cells, monocytes, and astrocytes, osteoblasts , keratinocytes, regenerating skeletal muscle, mast cells , and fibroblasts.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal
antibody specific for LIF has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any LIF present is bound by the immobilized antibody. An
enzyme-linked monoclonal antibody specific for LIF is added to the wells. Following a wash to remove any unbound antibody-enzyme reagent, a substrate solution is added to the wells
and color develops in proportion to the amount of LIF bound in the initial step. The color
development is stopped and the intensity of the color is measured. | 
