Lactoferrin is a glycoprotein that belongs to the iron transporter or transferrin family. It was originally isolated from bovine milk, where it is found as a minor protein component of whey proteins (see Whey Proteins). Lactoferrin contains 703 amino acids and has a molecular weight of 80 kilodaltons. In addition to its presence in milk, it is also found in exocrine secretions of mammals and is released from neutrophil granules during inflammation.
Lactoferrin is a glycoprotein from whey protein. One of the biological activities of lactoferrin comes from its powerful ability to bind iron (300 times that of serum transferrin). Low temperature processing ensures this potency. Digestion of lactoferrin liberates the immune supporting peptide lactoferricin B. Lactoferrin benefits intestinal health by promoting the growth of lactobacilli and bifidobacteria.
Lactoferrin is considered a multifunctional or multi-tasking protein. It appears to play several biological roles. Owing to its iron-binding properties, lactoferrin is thought to play a role in iron uptake by the intestinal mucosa of the suckling neonate. That is, it appears to be the source of iron for breast-fed infants. It also appears to have antibacterial, antiviral, antifungal, anti-inflammatory, antioxidant and immunomodulatory activities. Three isoforms of lactoferrin have been isolated: lactoferrin-alpha, lactoferrin-beta and lactoferrin-gamma. Lactoferrin-beta and lactoferrin-gamma have RNase activity, whereas lactoferrin-alpha does not. Receptors for lactoferrin are found in monocytes, lymphocytes, neutrophils, intestinal tissue and on certain bacteria. Lactoferrin is abbreviated LF and Lf. Bovine lactoferrin is abbreviated bLF.
Amount of lactoferrin required to eliminate harmful bacteria on a serving of meat is thousands of times less than the amount found in a single glass of milk. Potential applications of lactoferrin include carcass spray and finished-product treatment with minimal equipment investment required. Lactoferrin does not affect color, texture, nutritional value, or flavor of meat.
The possible antibacterial activity of supplemental lactoferrin might be accounted for, in part, by its ability to strongly bind iron. Iron is essential to support the growth of pathogenic bacteria. Lactoferrin may also inhibit the attachment of bacteria to the intestinal wall. A breakdown product of lactoferrin is the peptide lactoferricin. Lactoferricin, classified as a bioactive peptide, may also have antibacterial, as well as antiviral, activity. The possible antiviral activity of supplemental lactoferrin may be due to its inhibition of virus-cell fusion and viral entry into cells. A few mechanisms are proposed for lactoferrin's possible immunomodulatory activity. Lactoferrin may promote the growth and differentiation of T lymphocytes. Lactoferrin appears to bind uniquely in the region of major histocompatability (MHC) proteins and the CD4 and CD8 determinants on T4 (helper) and T8 (suppressor) lymphocytes; it bears sequence homologies with the MHC Class II determinant. Lactoferrin also appears to play a role in the regulation of cytokines and lymphokines, such as tumor necrosis (TNF)-alpha and interleukin (IL)-6. Lactoferrin's possible antioxidant activity may also contribute to its possible immunomodulatory activity.