Bovine Mammary Lactoferrin: Implications from Messenger Ribonucleic Acid (mRNA) Sequence and Regulation Contrary to Other Milk Proteins

Abstract

The regulation of bovine mammary lactoferrin, an important component of the antimicrobial defenses of the mammary gland, is poorly understood compared with the other milk proteins. The complete sequence for bovine lactoferrin mRNA shows it to be highly homologous to other lactoferrins and transferrins. However, regional differences in the deduced AA sequence of bovine lactoferrin compared with human lactoferrin and transferrin imply functional differences between them. Steady-state levels of bovine lactoferrin mRNA (by Northern blot) in the bovine mammary gland indicate that bovine lactoferrin expression is minimal in the developing and lactating gland but is strongly induced by mammary involution. The overall regulation of bovine lactoferrin in the mammary gland appears to be contrary to that of the other milk proteins. Features identified in the mRNA of bovine mammary lactoferrin may contribute to the differences in regulation between lactoferrin and other bovine milk proteins and to differences in concentrations of lactoferrin in milk across species. Lactoferrin secretion by bovine mammary cells grown in vitro does not appear to be dependent on prolactin and shows regulation by substratum, serum, and cell population to be different from that for casein. In contrast to casein, efficient secretion of lactoferrin from the cell does not require detachment of collagen substratum.

Staphylococcus aureuslipoteichoic acid triggers inflammation in the lactating bovine mammary gland

“…Increased concentrations of lactoferrin have been reported in milk of chronic S. aureus mastitis [20]. The main source of lactoferrin is likely to be mammary epithelial cells, which constitutively secrete lactoferrin but are also able to upregulate its synthesis [44], which has been demonstrated in vitro by co-culture with S. aureus [56]. Since lactoferrin is endowed with many activities related to the defence of the mammary gland [12,39,50], the response of mammary epithelial cells to LTA is likely to be of biological significance.…”

Characteristics of mammary secretions from Holstein cows at approximately 10 days before parturition: with or without intramammary infection

“…In contrast, synthesis and secretion of milk-specific proteins such as caseins, α-lactalbumin, and β-lactoglobulin are suppressed until a few days before parturition (Schanbacher et al 1993). In the last week of pregnancy, the colostral formation (including IgG 1 transfer) is considered to be largely developed in the bovine mammary gland (Jensen and Eberhart 1981;.…”

Effects of continuous lactation and short dry periods on mammary function and animal health

“…The mechanisms of survival and apoptosis in the mammary gland by local growth factors were reviewed by Lamote et al (2004). Among the local factors, Lactoferrin, IGFBP-5 and TGF-b1 are known factors that are elevated in stored milk after milk cessation (Schanbacher et al, 1993;Wilde et al, 1999). Although the role of TGF-b1 is not very well understood, it is upregulated when apoptosis occurs both in vitro and in vivo (Wilde et al, 1999).…”

“…These factors may also reduce the responsiveness of lymphocytes to antigen stimulation. There is an effective competition between citrate and lactoferrin for iron binding, and the resulting iron-citrate complex can be utilized by bacteria (Schanbacher et al, 1993). Moreover, highly accumulated milk in the udder at dry-off is an excellent medium for bacterial growth, which utilizes casein and lactose (Smith et al, 1985b;Breau and Oliver, 1986).…”