Influence Of Special IgY On The Intestinal Mucosal Immune In Mice

Egg yolk immunoglobulin (IgY), as the promising alternative of antibiotics, has attracted much attention for its effectiveness in control of infections caused by bacteria, fungi, and viruses. The reported possible bacteriostasis mechanisms of IgY were:altering the cell structure, binding adhesion molecule and improving the function of immune system. Other research found IgY could also effectively control non-intestinal infection, while the mechanism of bacteriostasis is not clear. In the present study, Salmonella typhimurium infected mice model was established to evaluate the effects of specific IgY on control of intestinal infection caused by S. typhimurium and the influence in inflammatory response of intestinal mucosal immune system.Different strains of mice were administered intragastrically with 4 bacteria following the pretreatment with or without antibiotics, the effects of different mice, bacteria, dosages injected and antibiotics applied on mice model of intestinal infection were determined in this study. The results indicated that Kunming mice administered intragastrically with Salmonella typhimurium could lead apparent intestinal infection, and a dose-dependent manner was found between the mortality and dosages injected, which indicated a successful model was established in this research.Specific IgY was produced by immunizing hens with formaldehyde-killed Salmonella typhimurium. The IgY,90% purity, was obtained from yolks by process of water dilution, two-step salt precipitation and ultrafiltration, which is easy to be industrialized. Enzyme-linked immunosorbent assay (ELISA) indicated the antibody titer of IgY could reach 10,000 at the highest and the titer that were higher than 5,000 could keep 8 weeks. In vitro study indicated specific IgY inhibited the growth of antigen strain at a dose-dependent manner.The mice were challenged by dose of 0.4ml 1010CFU/ml antigen followed by oral administration of 20mg/ml special antibody and non-special antibody, PBS and antibiotic were set as positive and blank control respectively. The life condition of mice was observed. The total RNA of intestine was purified 5 days after challenge. The expression level of inflammation factors, including TNF-α, IFN-γ, IL-6 and IL-10 were tested by real-time PCR. The results indicated that special IgY can reduce the expression of pro-inflammation factors and increase that of anti-inflammation factors in a significant difference (P<0.05). Thus, specific IgY played a protective role in intestinal infection caused by Salmonella typhimurium in mice.In conclusion, specific IgY against Salmonella typhimurium was achieved by immunizing hens, the effectiveness of specific IgY was proved by its reducing inflammation and mortality ability of mice in vivo study, which explored a new way to control infection diseases.