Antibodies against dextransucrase from Streptococcus mutans display anti-biofilm and growth suppressing activities

Abstract

Dextransucrase produced by Streptococcus mutans play an essential role in the formation of dental caries by synthesizing exopolysaccharides from sucrose, an important metabolite of the organism. In this study we report the location of dextransucrase in Streptococcus mutans cells and describe that antibodies raised against dextransucrase inhibited biofilm formation and reduced the adherence and hydrophobic properties of Streptococcus mutans. Western blot analysis and immunoelectron microscopy revealed that dextransucrase is located abundantly in the membrane fraction in S. mutans cells. Scanning electron microscopy and fluorescence microscopy revealed reduced cell density, impaired bioflim (plaque) formation in presence of dextransucrase antibodies. Genes associated with bioflim formation in S. mutans such as GtfB, GtfC, BrpA, relA, Smu630, vicK were down regulated (50–97%) in presence of the enzyme antibody. Presence of enzyme antibodies reduced adherence of S. mutans cells to glass surfaces by 58% and hydrophobicity by 55.2%. However dextransucrase antibodies did not affect acid production by S. mutans, under the experimental conditions. Immunohistochemistry studies with certain human samples displayed no cross reactivity with dextransucrase antibody. These findings suggest that antibodies against dextransucrase exhibit a profound inhibitory effect on the vital cariogenic factors of S. mutans and have no cross reactivity with human tissues tested, thus implying that dextransucrase could be a promising antigen to study its anticariogenic potential.