Characterization of specific egg yolk immunoglobulin (IgY) against mastitis-causing Staphylococcus aureus

摘要

To evaluate the in vitro activity of egg yolk immunoglobulin (IgY) against mastitis-causing Staphylococcus aureus. Specific IgY was produced by immunizing hens with formaldehyde-killed Staph. aureus, using a bacterial strain known to cause mastitis. The IgY, of 94% purity, was obtained from yolks by water dilution, salt precipitations, ultrafiltration and gel filtration. ELISA indicated that the IgY produced was specific to the antigen and five Staph. aureus isolates obtained from mastitic cows. The growth of Staph. aureus was inhibited by specific IgY at concentrations from 1 to 10 mg mlp# in a dose-dependent manner. The phagocytosis of Staph. aureus by milk macrophages was enhanced in the presence of specific IgY with the highest phagocytic percentage being 30% higher than that without IgY (P < 0p"05). The specific IgY against mastitis-causing Staph. aureus inhibited the growth of Staph. aureus and enhanced the phagocytosis of Staph. aureus by milk macrophages. Specific IgY would be a potential treatment for bovine mastitis.