AssayPro—Human Lactoferrin ELI

Introduction
Lactoferrin is an 80 kDa iron-binding glycoprotein produced by many exocrine glands with a major constituent in the secondary granules of neutroplilic leukocytes. Serum lactoferrin concentration is much higher during inflammation (1). Lactoferrin is known to be an immune modulator or enhancer due to specific receptors for lactoferrin that are found on many key immune cells such as lymphocytes, monocytes, and macrophages. Lactoferrin is known to be directly involved in the up-regulation of natural killer (NK) cell activity (2). Lactoferrin is present in maternal milk, saliva, tears, vaginal secretions, semen, bronchoalveolar lavage fluid, and specific granules of polymorphonuclear leukocytes (PMNs) (3). Lactoferrin is found mainly in the oral cavity where it can come into direct contact with pathogens such as viruses, bacteria, etc. Lactoferrin directly inhibits viruses by binding to viral receptor sites, thus preventing the virus from infecting healthy cells. Lactoferrin has a direct bacteriacidal function to certain bacteria such as Streptococcus mutans, Vibrio cholerae, Escherichia coli, Actinobacillus actinomycetemcomitans, and Legionella pneumophila (2-4). Also, it has a bacteriostatic effect that deprives iron-requiring bacteria of this essential growth nutrient (4). Lactoferrin is also considered an antioxidant that scavenges free iron, helping to prevent uncontrolled iron based free radical reactions, thus protecting certain cells from peroxidation (2).

Principle of the Assay
The AssayMax Human Lactoferrin ELISA (Enzyme-Linked Immunosorbent Assay) kit is designed for detection of human lactoferrin in plasma, serum, urine, saliva, milk, and cell culture samples. This assay employs a quantitative sandwich enzyme immunoassay technique, which measures lactoferrin in less than 4 hours. A polyclonal antibody specific for lactoferrin has been pre-coated onto a 96-well microplate with removable strips. Lactoferrin in standards and samples is sandwiched by the immobilized antibody and a biotinylated polyclonal antibody specific for lactoferrin, 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.