Production and Characterization of Species-Specific Monoclonal Antibodies against Actinomyces naeslundii and Lactobacillus casei

Abstract

Dental caries is a disease induced by a few cariogenic bacterial species. Quantitative detection of these cariogenic bacteria could provide useful information for caries risk assessment. In this study, we developed highly species-specific monoclonal antibodies (MAbs) against the type strains of Actinomyces naeslundii ATCC 12104 and Lactobacillus casei ATCC 11578. Assayed with immunoprecipitation and immunofluorescent microscopy, these antibodies showed high sensitivities and specificities in detecting A. naeslundii and L. casei in saliva. Examining 100 saliva samples using these MAb-based techniques, we found that the number of A. naeslundii in saliva ranges from 0.5 × 10⁴ to 4.8 × 10⁵ and that the number of L. casei in saliva ranges from 1 × 10⁴ to 1.2 × 10⁶. With fluorescent imaging techniques and confocal laser scanning microscopy (CLSM), these antibodies were used to visualize A. naeslundii and L. casei within dental plaques derived from stimulated whole human saliva in vitro. The study demonstrated that these MAbs were also able to effectively detect A. naeslundii and L. casei in plaque.