预期应用
ELISA法定量测定小鼠血清、血浆、细胞培养物上清或其它相关液体中IL-5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IL-5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IL-5抗原、生物素化的抗小鼠IL-5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IL-5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 mouse IL-5 concentrations in cell culture supernates, serum, and plasma.
Introduction
Il-5 is a 135 amino acid (aa) polypeptide with a predicted mass of 12.5 kDa. It is secreted by a restricted number of mesenchymal cell types. In its native state, mature IL-5 is synthesized as a 115 aa, highly glycosylated 22 kDa monomer that forms a 40-50 kDa disulfide-linked homodimer. Although the content of carbohydrate is high, carbohydrate is not needed for bioactivity. Monomeric IL-5 has no activity and requires a homodimer for function, which is in contrast to the receptor-related IL-3 and GM-CSF cytokines that exist only as monomers. Just as one IL-3 and GM-CSF monomer binds to one receptor, one IL-5 homodimer is able to engage only one IL-5 receptor. It has been suggested that IL-5 (as a dimmer) undergoes a general conformational change after binding to one receptor molecule and this change precludes binding to a second receptor. Mouse and mouse mature IL-5 are 71% identical at the aa level.
IL-5 appears to perform a number of functions on eosinophils including growth and differentiation, the down modulation of Mac-1, the upregulation of receptors for IgA and IgG, the stimulation of lipid mediator (leukotriene C4 and PAF) secretion and the induction of granule release. IL-5 may act in an adjunct fashion plays, however, the exact role is unclear. Finally, there is a great deal of interest in the interaction between IL-5 and the CC chemokine eotaxin. Studies suggest that inflammatory-induced and locally produced IL-5 and eotaxin may act on the bone marrow in a cooperative manner.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal
antibody specific for IL-5 has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any IL-5 present is bound by the immobilized antibody. An
enzyme-linked monoclonal antibody specific for IL-5 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 IL-5 bound in the initial step. The color
development is stopped and the intensity of the color is measured. | 
