The Regulation Of Egg Yolk Antibodies On The Intestinal Mucosal Immune Of Mice In Intestinal Infection Model

Chicken egg yolk immunoglobulin, referred to as immunoglobulin Y (IgY) presents a promising approach for the passive immunization trials against intestinal infections.We tend to understand whether specific IgYcould modulate mucosal immune response in mice challenged with Salmonella typhimurium,such as cytokine expression and the number of lymphocytes and the phagocytic activity of macrophages and so on.Kunming mice were randomly divided into four groups with each of10.After streptomycin pretreatment (5g/L last for2days),the mice were given0.4ml of S. typhimurium at a concentration of109cfu/ml twice at0and24h of the experiment. After the second S. typhimurium challenge24h, the mice in unchallenged group received no treatment, whereas the mice in the remaining three groups were each given intraperitoneally0.4ml of specific IgY, non-specific IgY at a concentration of20mg/mL, or0.4ml of PBS once a day for7consecutive days.On d7,the jejunum of the mice were collected.The protective effect of specific IgY were analyzed by Histopathology.The ultrastructure of intestinal epithelial cells were observed by transmission electron microscope. The content of myeloperoxidase was analyzed by the means of ELISA.Lymphocyte populations were analyzed by immunohistochemistry. After7days, mice in the specific IgY-treated group and the unchallenged group had similar body weight gains that were significant higher (P<0.05) than those challenged and untreated, or treated with nonspecific IgY. Oral IgY therapy alleviated the damage of S. typhimurium treatment,and also oral specific IgY therapy effectively reduced jejunum ulceration, transmural inflammation,and edema better than the nonspecific IgY.In intestine,specific IgY prevented the increase in MPO content induced by S. typhimurium and thus it alleviated the excessive activation of neutrophils. S. typhimurium increased the number of T lymphocytes(150%,P<0.001) and the cytotoxic lymphocyte populations of T-γδcells (29%,P<0.001).Specific IgY decreased the effects of S. typhimurium on the lymphocyte populations.The results suggest that oral specific IgY not only can protect against the challenge infection but also it can modulate the inflammation and the number of lymphocyte populations of diffuse Gut-associated Lymphoid Tissue(GALT).In vitro studies,the influence of specific IgY on the phagocytic activity of macrophages and on the content of NO molecule was analyzed by method of flow cytometer and ELISA.The FITC was used for the labeling of macrophages and after culture the macrophages with S. typhimurium and specific IgY or nonspecific IgY.the phagocytic ratio of macrophages was detected by flow cytometer.Also we detected the content of NO after coculture,the results showed that5mg/ml concentration of specific IgY can markedly enhance phagocytosis rate of macrophage and significantly reduce the increase of NO content caused by S. typhimurium.In summary,the study researched the influence of specific IgY on MPO content,the T lymphocyte and macrophages which associated with the mucosal immune response from in vivo and in vitro separately.The aim was to reveal regulation of specific IgY on the mucosal immune responses in mice infected by S. typhimurium,which. is avery important supplement for the mechanism of using specific IgY in preventing and controlling various infectious diseases.