Protection Of Egg Yolk Immunoglobulin On Mice Against Septicemia

Septicemia is life-threatening medical condition caused by various microorganisms entering the human bloodstream triggering an uncontrolled inflammatory reaction. Currently, antibiotic was ususlly used to treat septicemia, but drug resistance already more serious. Egg yolk immunoglobulin provides an effective, safe and inexpensive source of antibodies for intestinal diseases caused by bacteria or viruses. It is one of the most promising alternatives to antibiotics. Currently its application is limited in treatments of intestinal diseases; objective of the thesis was to study the protection of IgY to the septicemia mice model induced by intravenously staphylococcus aureus.Inactivated whole cell of S. aureus was used as an antigen to immunize laying hens, and then purified specific IgY. The optimal concentration of formalin-killed S.aureus was found to be0.4mg/ml, which resulted in the greatest and most stable antibody titer. The highest titer of IgY peaked at1:18000after first immunity8week. The final purity of IgY after water dilution, two-step salt precipitation and ultrafiltration was83.4%. The growth of S.aureus in culture medium was inhibited by specific IgY at5mg/ml in vitro experiment. The result of immunofluorescence experiment showed that specific IgY could specifically bind with S.aureus.Establish septicemia mice modle through intravenously S.aureus. Specific IgY was given orally or intraperitoneally to mice against septicemia. Results showed that the minimum lethal dose (MLD) of septicemia mice induced intravenously by S.aureus was4><107CFU. Specific IgY was given orally or intraperitoneally to mice for2days before challenging with S.aureus and for3days after challenge. The research results indicated that there were no differences between control group and IgY fed orally group in mortality rate (P>0.05). The mortality rate of control group was100%, and that of IgY injected intraperitoneally group was0%.There were significant differences between the two groups (P<0.01). The results suggested that specific IgY provided protection to the septicemia by the administration of intraperitoneal injection.