Background：Serotransferrin(TF) is a 77 kDa secreted protein which is also named as transferrin, siderophilin, beta-1 metal-binding globulin and belongs to a family of homologous iron-binding glycoproteins that encompasses lactoferrin(found both intracellular and in secretions, including milk), melanotrasferrin(present on melanoma cells) and ovotransferrin(present in egg white). TF is a multi-function protein with a primary role in transporting iron in a safe, redox-inactive state from absorption to utilization or storage sites around the body. The association of Tf with the immune system derives from its ability to restrict serum free-iron levels, creating low-iron environments where the infection capacity of pathogenic microorganisms is limited. TF is expressed predominantly in the liver and secreted in plasma, but lower amounts can be synthesized in other tissues such as the brain and the testis
