Changes in lactoferrin immunoglobulin G bovine serum albumin and alpha-lactalbumin during acute experimental and natural coliform mastitis in cows.

摘要

An experimentally induced Escherichia coli infection of a bovine mammary gland resulted in a 30-fold increase in lactoferrin (Lf) concentration in the mammary secretion by 90 h postinoculation and a 4-fold increase in total daily production of Lf by 264 h postinoculation in the infected quarter. A simultaneous rise and fall of bovine serum albumin (BSA) and immunoglobulin G (IgG) concentrations occurred during the acute phase of the infection. Peak BSA and IgG levels were reached 36 h before peak Lf levels. BSA concentrations declined rapidly after the acute phase, whereas IgG and Lf levels remained elevated and decreased slowly as the infection subsided. A decline in alpha-lactalbumin concentration by 48 h postinoculation indicated decreased synthetic capability. The increased Lf production may be a result of a specific response of secretory tissue to inflammatory agents and thus the infectious process. Analogous changes in Lf, IgG, and BSA were observed during a natural coliform infection. Sephadex G-200 chromatography of mastitis skim milk showed that Lf approximated the monomer (molecular weight 77,100) early in infections progressed and abated, the apparent molecular weight of Lf increased to approximately that of the trimer and subsequently decreased to about 1.5 times that of the monomer.