As we know, for antigens with multiple epitopes, double sandwich ELISA (Double Sandwich ELISA) can be applied to the quantitative detection of target antigens or antibodies. While for small molecule or hapten, as lacking of more than two binding sites for double sandwich detection, double sandwich method is not suitable. In this case, competitive inhibition method can be applied to detect target molecules. Competitive inhibition ELISA also can be called blocking ELISA, its main principle is the competive binding of the antigens within the samples and the certain amount of labeled-antigens with antibody on the solid-phase. The more amount of antigen in samples, the less labeled antigen ......2015-05-14

In ELISA experiments, researchers often encounter samples with low OD, including serum, plasma, tissue homogenate, cell lysate, etc. Assuming the customer's operation is right, the standard curve is also good, in this situation the reasons can be analyzed in two ways. On one hand, the content of the sample itself can be detected, but some operations cause the samples measured value become out of the detection range of Elisa kit; On the other hand, low concentration of analyte in the sample itself. Following we’ll analyze in these two aspects and raise their solutions. 1. When the content of target molecules itself can be detected, what factors may cause low measured value......2015-05-05

Since the 1970s, ELISA, as a simple and rapid method for the quantitative determination trace protein, has been widely used in many fields of biology and medicine. Enzyme linked immunosorbent assay (ELISA, Enzyme-Linked Immunosorbnent Assay) is a new immunoassay technique based on the solid-phased antigen or antibody and enzyme-labeled antigen or antibody binding. It can be divided into those four categories: direct ELISA, indirect ELISA, sandwich ELISA and competitive inhibition ELISA. And wherein, the most widely used method for quantitative detection of the antigen or antibody is double sandwich ELISA, which is obtained by a known antigen or antibody adsorbed on a solid phase carri......2015-05-05

An autoantibody is an antibody (a type of protein) produced by the immune system that is directed against one or more of the individual's own tissues, organs,cells and cellular components (including proteins and nucleic acids). Normally, immune cells can discriminate self from non-self. A normal body does not respond to its own antigens. This self-defense mechanism of immune system is called Immune Tolerance. The body maintain normal growth, development and survival by immune tolerance systerm. Once this system is destroyed, the immune system recognize one or more of the body's normal constituents as "non-self", and leading to production of pathological autoantibodi......2015-05-05

Tumor protein p53 (P53, TP53) is an important protein coded by TP53 gene, it could inhibit tumor through regulation of cell cycle. Previously the main research directions on p53 are the function and mechanism in tumor inhibition. Previous studies showed that the calculated molecular weight of p53 is 43.7kDa, according to the amino acids of the protein, but the molecular weight (MW) shown in SDS-PAGE is 53kDa. The reason leads to this difference in molecular weight lies in the abundance of proline residue in the protein, and this phenomenon shows not only in human p53, but also in p53 of other species, including rat, mouse, frog and so on. The MW difference is in accordance with the p......2015-04-22

Transforming growth factor beta (TGF-β) is a group of transforming growth factor beta superfamily of cytokines, which can control proliferation, cellular differentiation, and other functions in most cells. It is widely located in normal cells and transformed cells. It is a type of cytokine which plays a role in promotion of embryonic development, immunomodulatory effect, growth suppression, wound healing, angiogenesis, extracellular matrix precipitation and so on. This cytokine can promote the transformation of normal fibroblasts from adherent growth to suspension. Therefore, it is named. TGF-β exists in Mammals at least three isoforms called TGF-β1, TGF-β2 and TGF......2015-04-22