预期应用
ELISA法定量测定人血清、血浆或其它相关液体中补体1q(C1q)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C1q水平。用纯化的抗体包被微孔板，制成固相抗体，往包被抗体的微孔中依次加入C1q、生物素化的抗人C1q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C1q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 Complement 1q,C1q concentrations in cell culture supernates, serum, and plasma.
Introduction
C1q is a 400 KDa protein formed from 18 peptide chains in 3 subunits of 6. Each 6 peptide subunit consists of a Y-shaped pair of triple peptide helices joined at the stem and ending in a globular non-helical head.The C1 protein, showing subunits C1r, C1s, and the C1q tails.The 80 amino-acid helical component of each triple peptide contain many Gly-X-Y sequences,where X and Y are proline, isoleucine or hydroxylysine; they therefore strongly resemble collagen fibrils.
C1q is part of the activation arm of complement.It is the first element in the classic complement activation pathway that starts on binding of C1q to the antigen,either directly or through an antibody-antigen complex.C1q then interacts with and activates several proteases(C1r,C1s,C2-C4) that amplify the original response and initiate opsonization,anaphylactic reactions that attract phagocytes,and that finally directly attack the cell membrane through the membrane attack complex (MAC). In addition,C1q appears to have other potential functions through cell-specific receptors. C1q is alarge molecule made up of 18 polypeptide chain s(6 of A,6 of B,and 6 of C)held together by acombination of covalent(disulfide) and noncovalent bonds.When assembled,the C1q full molecule has two distinct regions:a globular head and a longtail.Most of the antibodies raised against C1q specific to the secondary structure of the assembled chains and are nonreactive to the amino acid sequence of each chain.The tightly bound individual polypeptide chains are difficult to separate from this complex,which requires long incubations under reducing conditions and high urea concentrations.Several proteins have globular domains similar to C1q.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for C1q has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any C1q present is bound by the immobilized antibody. An enzyme-linked polyclonal antibody specific for C1q 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 C1q bound in the initial step. The color development is stopped and the intensity of the color is measured.
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