Preparation And Studies On Egg Yolk Antibody Against Dental Caries

Mutans streptococci are the primary cariogenic agents, and Streptococcus mutans and Streptococcus sobrinus are believed to have the closest relationship with human caries. Laying hens were immunized with S. sobrinus, and their serum anti-S. sobrinus antibody can be transferred to the egg yolk. In this paper, high activity of yolk antibody, extracted from egg yolk, can be obtained .The optimum pH for S. sobrinus was about 7. 0, and it can grow well when 5% sucrose was added in. Further studies showed that P-Aminobenzoic acid(PABA) had an ability to promote the growth of S. sobrinus and the optimum concentration was 10-4g/L.Glucosyltransferase (GTF) is believed to play a key role in the formation of dental plaque. The enzyme was purified with a series of steps that were as follows ultrasonic, ammonium sulphate precipitation, DEAE - Sepharose ion-exchange and Superdex 200 gel-filtration column chromatography. After being purified by steps mentioned above, the activity of GTF attained 1. 91u/mg and was 20. 5 times higher than that of primary GTF. Character of GTF was studied and the result indicated that the optimum temperature of its reaction was 37癈 and pH was 6. 8.After immunization of hens, the antibody against S. sobrinus had been maintaining at a high level during a certain time. The study on frequency of laying eggs show that immunity had a little effect on it and the immunology procedure was reasonable. At last, purity of yolk antibody was 95. 7% and its molecular weight was about 198000.The activity of yolk antibody was checked by ELISA. The result indicated that when the antigen was S. sobrinus, the activity of yolk antibody against S. sobrinus was 16 times than the activity of general IgY; and when the antigen was GTF , the activity of yolk antibody was 4 times than the activity of general IgY.Test on yolk antibody against S. sobrinus showed that yolk antibody might have a protective effect against dental plaque caused by S. sobrinus. At the same time, yolk antibody had high inhibition to the acid production of S. sobrinus. Test on oral cavity found that yolk antibody can reduce the content of S. mutans and S. sobrinus, prevention of dental caries can be obtained.