PASSIVE-IMMUNIZATION AGAINST DENTAL PLAQUE-FORMATION IN HUMANS - EFFECT OF A MOUTH RINSE CONTAINING EGG-YOLK ANTIBODIES (IGY) SPECIFIC TO STREPTOCOCCUS-MUTANS

Passive immunization involving the delivery of antibodies specific to pathogens of infectious diseases to the host has been an attractive ap proach to establish protective immunity against a variety of microbial pathogens, including Streptococcus mutans, which is the principal eti ologic agent of dental caries in humans. The overall purpose of the pr esent study was to determine the effectiveness of a mouth rinse contai ning antibodies to S. mutans in preventing the establishment of this b acterium in dental plaque of humans. The antibodies were derived from egg yolks obtained from hens immunized with whole cells of S. mutans g rown in sucrose-containing medium. The immunoglobulin derived from the yolks (IgY) of immunized hens was characterized in vitro and in vivo in human volunteers. Cross-reactivity tests showed that immune IgY rea cted with every serotype, except serotype b, which had lost its GTase activity, when the bacteria were cultured in sucrose-containing medium . Immune IgY inhibited S. mutans adherence to saliva-coated hydroxyapa tite discs by 59.2%, while control IgY caused an inhibition of only 8. 2%. In the short-term (4-hour) test using a mouth rinse containing 10% sucrose, immune IgY decreased the ratio of the percentage of S, mutan s per total streptococci in saliva. In the long-term (7-day) test usin g a mouth rinse without sucrose, the ratio in saliva was not significa ntly reduced in the volunteers using the immune IgY due to the large s tandard deviation. However, comparing the ratios of the percentage of S. mutans per total streptococci in plaque of individual subjects, the re was a tendency for a reduction of the ratios in the volunteers rece iving the mouth rinse containing immune IgY. These results support the effectiveness of IgY with specificity to S. mutans grown in the prese nce of sucrose as an efficient method to control the colonization of m utans streptococci in the oral cavity of humans.