Small molecule lactoferrin with an inflammatory effect but no apparent antibacterial activity in mastitic mammary gland secretion

We have identified various lactoferrin (Lf molecules in mastitic mammary gland secretions (MGSS), and these Lf molecules were exanined for their physiological function in MG. These Lf molecules were isolated by Con A affinity chromatoglaphy, and then analyzed by various electrophoresis methods and N-terminal amino acid sequencing. The low Con A affinity Lf was found to have low molecular peptides as compared with the 86 kDa of the high Con A affinity Lf, which is usually detected in healthy MGSs. The N-terminal amino acid sequence of each of the small molecular Lfs were confirmed as fragments of 86 kDa Lf. This low Con A affinity Lf stimulated spleen adherent cells to produce more Of than 86 kDa) Lf. Furthermore, the low Con A affinity Lf showed low antibacterial activity against E. coli and S. aureus, and had decreased iron-binding capacity in comparison with 86 kDa Lf. Moreover, the 86 kDa Lf could stimulate bovine T cells or macrophages to produce IFN-gamma, IL-4, IL-6, and IL-1-aloha. However low Con A affinity Lf induced the production of TNF alpha, but not physiological T cell or macrophage cytokines. It was also found that when the healthy MGS of dry cows were injected with the low Con A affinity Lf, there was an increase in polymorphonuclear cells together with TNF alpha, MCP-1, and IL-8 production. These results suggested that low Con A affinity Lf in mastitic MGSS differed from 86 kDa Lf in physiological characteristics, and, that it induced an in flanmmatory reaction in MGs.