Dental root decay is prevalent among older individuals as their gum recesses exposing Dental root surface to attack by cariogenic bacteria. In a study involving 449 subjects of an age range of 79-101 years, 96% had coronal decay experiences, and 64% had root caries experience with 23% of the group having untreated root caries (ADA News Releases, 2000). Streptococcus mutans, an etiologic agent in the development of coronal caries, has also been implicated in Dental root decay; data in support of this implication include the finding of S. mutans in Dental root section, its ability to bind collagen, and to degrade FALGPA, a known synthetic peptide substrate for collagenase. Bacterial collagenases are considered as virulence factors as they facilitate the invasion and destruction of host tissues by the pathogens. It is not yet known whether S. mutans produces a true collagenase enzyme. Considering the increase in incidence of Dental root caries as the population lives longer, the long-term goal of the current study is to develop effective and safe methods to control this disease, and improve the nutrition and quality of life of the population at risk. In order to determine whether the collagenolytic enzyme in S. mutans is a good candidate antigen for vaccine development, the Specific Aim of the current research is to learn more about the S. mutans enzyme in order to explore this avenue. A putative S. mutans collagenase gene has been obtained previously, and sequence analysis showed a high homology with the 35-kDa collagenase of various clinical isolates of Porphyromonas gingivalis, a bacterium causing periodontitis. The plan is to clone the 1.2 kbp putative collagenase coding sequence into an expression plasmid under the control of a strong promoter in order to obtain the corresponding protein, which in turn will be isolated and characterized by biochemical methods. Antibody will be prepared against the S. mutans enzyme and tested for the ability to block collagen binding and/or collagen degrading properties. The data obtained will be compared with other known bacterial collagenases. This information is essential in determining future directions for research on the role of S. mutans in Dental root caries, and other diseases that may involve collagen binding and collagen degrading activity such as periodontitis and endocarditis.
| Han, Thomas K; Dao, My Lien (2007) Enhancement of salivary IgA response to a DNA vaccine against Streptococcus mutans wall-associated protein A in mice by plasmid-based adjuvants. J Med Microbiol 56:675-80 |
