Human Complement Factor D ELIS

Introduction
Complement Factor D (FD), also known as adipsin, is a serine protease secreted by adipocytes into the bloodstream and a component of the alternative complement pathway. It is a 24 kDa single chain glycoprotein with 222 amino acids and has a high level of expression in fat (1-3). Human FD cleaves factor B bound to C3b, generating the alternative pathway C3 convertase C3bBb and releasing the Ba fragment. Human FD plays a major role in humoral suppression of infectious agents. The deficiency of FD increases susceptibility to infections and their recurrence (4).

Principle of the Assay
The AssayMax Human Complement Factor D (FD) ELISA kit is designed for detection of human FD in plasma, serum, saliva, milk, and cell culture samples. This assay employs a quantitative sandwich enzyme immunoassay technique that measures FD in less than 4 hours. A polyclonal antibody specific for FD has been pre-coated onto a 96-well microplate with removable strips. Human FD in standards and samples is sandwiched by the immobilized antibody and the biotinylated polyclonal antibody specific for human FD, which is recognized by a streptavidin-peroxidase conjugate. All unbound material is then washed away and a peroxidase enzyme substrate is added. The color development is stopped and the intensity of the color is measured.