Novel Oral Bacterial Surface Proteins for Drug Targeting

Emory University
posted on 01/16/2012

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Applications

• DNA and protein sequences can be used for vaccine design or drug targeting.
• Drugs targeting these proteins could be used in dentistry to prevent tooth decay.

Highlights

• The proteins are expressed extracellularly, making them attractive for drug or vaccine targeting.

Technical Summary

Oral streptococci bacteria (S. mitus and S. oralis) are normally present in the mouth and oral cavities of healthy human beings. As they are the major first colonizers in oral biofilm, they occasionally become pathogenic and cause gingivitis and caries (tooth decay). If these bacteria enter the bloodstream, as can happen during oral surgery, this can lead to infective endocarditis when the bacteria reach the heart. Gingivitis and caries affect a large number of people, with an estimated 50-80% of the adult population being affected by gingivitis and 90% of the population affected by caries. The prevalence is significantly higher in developing countries and lower income communities, due to inadequate oral care.

Biofilms develop as bacteria stick to the gums and oral cavities via a pilus structure. Researchers at Emory University discovered and cloned the two genes responsible for pilus formation in oral streptococci bacteria (PitA and PitB). PitB encodes the pilus backbone protein and PitA encodes a pilus accessory protein. Their studies showed that deletion of these genes eliminates pili formation in the bacteria. The PitA and PitB  proteins are expressed on the surface of the cell, making them attractive for drug and vaccine design (either independently or in conjunction with other medications). Current anti-bacterial mouthwashes non-specifically target all bacteria, including bacteria that are beneficial in breaking down food. Drugs or vaccines targeting pili in biofilm-forming bacteria present a unique approach for improving oral health.