Study on the Stability of Microencapsulated Antibody prepared from the Yolk of Eggs Laid by Hens Immunized with urease from Helicobater pylori
| Autor: | Yang-Chun Lee, 李陽春 |
|---|---|
| Rok vydání: | 1999 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 87 Numerous epidemiological studies indicate a causative relationship between the presence of Helicobater pylori and histologically confirmed gastritis,gastric ulcer and doudenal ulcers.The most notable feature of H. pylori is the production of extremely active urease that could be isolated from cells.Many basic researches on H. pylori were conducted in resent decade.However,applications of H. pylori as the antigen for passive immunization against gastric ulcers and duodenal ulcers have not been reported.Since passive immunization requires a large quanity of antibody,therefore the search for cheap and abundent source of antibody become the important issue.Besides,orally administrated antibodies are sensitive to protease and gastric acid and the consideration for protection of antibody against acid and proteases upon ingestion have to be improved.In this study,purified urease from H. pylori was used as antigen to intramuscularly immunize 10 hens on the thighs.The relative ELISA(enzyme-linked immunosorbent assay) value of antibody in serum and egg yolk,diluted 1,000 folds,against urease was determined during the immunization period.To improve the antibody stability against acid and protease,the collected egg yolks were microencapsulated with various concentration(10 and 15%)of materials(cyclodextrin,gum arabic,soluble starch and casein)by a laboratory-prepared spray-drier(dried at 58±3℃).For protease test,the microencapsulated egg yolk powder was hydrolyzed with protease(pepsin at pH2.0 or 4.0;trypsin,chymotrypsin at pH 7.6) and the relative ELISA value against urease as well as the degree of hydrolysis was determined using spray-dried yolk powder as control.Liposomes of IgY(immunoglobulin in yolk) were also prepared,by repeated dehydration and rehydration of lecithin and cholesterol mixture,to investigate the effect of liposome composition on IgY stability against acid (Ph 1.8 and 2.8)and pepsin(15μg/ml).Meanwhile,the encapsulation efficiency of IgY in liposomes was discussed and compared with that of BSA.Results showed that the relative ELISA value of IgY in both serum and yolk began to increase in the third weel of immunization.The mcroencapsulation of egg yolk with 10 and 20% cyclodextrin,soluble starch,gum arabic and casein showed effective protection effect on the stability of IgY against acid and proteases.The highest encapsulation efficiency of BSA and IgY in liposomes prepared with the ratio of lecithin to cholesterol 1/0.25 was found to be 71 and 69%,respectively.However,liposomes with higher cholesterol content (lecithin/cholesterol=1/1) showed more effective protection effect on IgY against acid (pH 1.8 and 2.8) and pepsin hydrolysis. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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