Lactoferrin (Lf), also known as lactotransferrin, is a multifunctional, iron binding glycoprotein that is widely present in mammalian tears, saliva, milk and mucosal secretions. In tears, Lf is one of the eye’s main immunological defense agents and plays a well-documented and critical role in the maintenance of ocular surface health.
Lactoferrin’s biological actions include:
- Modulation of ocular inflammatory response
- Regulation of normal cell growth
- Protection against infections by inhibiting viral, bacterial or fungal growth
Secreted directly by the epithelial acinar cells of the lacrimal gland, lactoferrin is considered a bacteriostatic in tear film and is necessary for the formation of the principle natural ocular antibiotic, lysozyme.
As a biomarker, lactoferrin has been studied extensively and has long been established as a highly accurate test in assessing the secretory function of the Lacrimal Gland.
In the tear film, lactoferrin accounts for approximately 25% of total proteins by weight. Lower tear film lactoferrin levels are reported in dry eye, herpes simplex keratitis and systemic infections such as HIV and Hepatitis C.