Description
Principle of the Assay::The Mouse Endostatin ELISA (Enzyme-Linked Immunosorbent Assay) kit is an in vitro enzyme-linked immunosorbent assay for the quantitative measurement of Mouse Endostatin in Cell Culture Supernatants, Serum, Plasma. This assay employs an antibody specific for Mouse Endostatin coated on a 96-well plate. Standards and samples are pipetted into the wells and Endostatin present in a sample is bound to the wells by the immobilized antibody. The wells are washed and biotinylated anti-Mouse Endostatin antibody is added. After washing away unbound biotinylated antibody, HRP-conjugated streptavidin is pipetted to the wells. The wells are again washed, a TMB substrate solution is added to the wells and color develops in proportion to the amount of Endostatin bound. The Stop Solution changes the color from blue to yellow, and the intensity of the color is measured at 450 nm.
Background/Introduction: Endostatin is a naturally-occurring 20-kDa C-terminal fragment derived from type XVIII collagen. It is reported to serve as an anti-angiogenic agent, similar to angiostatin and thrombospondin. And It is produced by proteolytic cleavage of collagen XVIII, a member of the multiplexin family that is characterized by interruptions in the triple helix creating multiple domains, by proteases such as cathepsins. Using a genomic clone as a probe for fluorescence in situ hybridization, Endostatin was mapped the COL18A1 gene to 21q22.3. By immunoprecipitation analysis using membrane fractions of human mammary epithelial cells, It showed that endostatin specifically bound to cell surface nucleolin with high affinity. Blockage of nucleolin with neutralizing antibody or knockdown of nucleolin by RNA interference countered the antiendothelial activity of endostatin and abrogated its antiangiogenic and antitumor activity in vivo