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S. Mutans Cells (s._mutan + cell)

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Medical Sciences	100%

Selected Abstracts

Induction of neutralizing antibodies in mice immunized with an amino-terminal polypeptide of Streptococcus mutans P1 protein produced by a recombinant Bacillus subtilis strain

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2010
Milene B. Tavares
Abstract The oral pathogen Streptococcus mutans expresses a surface protein, P1, which interacts with the salivary pellicle on the tooth surface or with fluid-phase saliva, resulting in bacterial adhesion or aggregation, respectively. P1 is a target of protective immunity. Its N-terminal region has been associated with adhesion and aggregation functions and contains epitopes recognized by efficacious antibodies. In this study, we used Bacillus subtilis, a gram-positive expression host, to produce a recombinant N-terminal polypeptide of P1 (P139,512) derived from the S. mutans strain UA159. Purified P139,512 reacted with an anti-full-length P1 antiserum as well as one raised against intact S. mutans cells, indicating preserved antigenicity. Immunization of mice with soluble and heat-denatured P139,512 induced antibodies that reacted specifically with native P1 on the surface of S. mutans cells. The anti-P139,512 antiserum was as effective at blocking saliva-mediated aggregation of S. mutans cells and better at blocking bacterial adhesion to saliva-coated plastic surfaces compared with the anti-full-length P1 antiserum. In addition, adsorption of the anti-P1 antiserum with P139,512 eliminated its ability to block the adhesion of S. mutans cells to abiotic surfaces. The present results indicate that P139,512, expressed and purified from a recombinant B. subtilis strain, maintains important immunological features of the native protein and represents an additional tool for the development of anticaries vaccines. [source]

Role of prolipoprotein diacylglyceryl transferase (Lgt) and lipoprotein-specific signal peptidase II (LspA) in localization and physiological function of lipoprotein MsmE in Streptococcus mutans

MOLECULAR ORAL MICROBIOLOGY, Issue 6 2008
T. Arimoto
Introduction:, To clarify the role that prolipoprotein diacylglyceryl transferase (Lgt) and lipoprotein-specific signal peptidase II (LspA) play in the physiological function of MsmE, we constructed lgt -deficient and lspA -deficient mutants of Streptococcus mutans 109c and examined the potential role of Lgt and LspA in membrane anchoring and growth in a melibiose medium of S. mutans. Methods:, The lgt -, lspA -, and msmE -deficient mutants of S. mutans 109c were constructed by double-crossover recombination of their respective genes. Localization of MsmE was demonstrated by Western blot analysis with an MsmE antiserum. The growth of S. mutans cells was examined in a Trypton medium containing melibiose or glucose. Results:, In the S. mutans lgt mutant, localization of the surface lipoprotein MsmE changed with the culture supernatant. The growth of the S. mutans lgt and lspA mutants was remarkably reduced in the melibiose medium; however, growth was recovered in the strains complemented with the lgt or the lspA gene. Therefore, lipid-modification by Lgt and subsequent signal peptide cleavage by LspA were crucial for membrane anchoring and the physiological function of MsmE in S. mutans. Conclusion:, These results demonstrate that MsmE is required for melibiose metabolism in S. mutans and that modification by Lgt and LspA are important processes for the physiological function of MsmE. [source]

Effects of antibodies against a fusion protein consisting of parts of cell surface protein antigen and glucosyltransferase of Streptococcus sobrinus on cell adhesion of mutans streptococci

MOLECULAR ORAL MICROBIOLOGY, Issue 1 2008
T. Kawato
Background/aims:, The cell surface protein antigen (PAg) and glucosyltransferases (GTFs) produced by Streptococcus sobrinus are considered to be major colonization factors of the organism. Methods:, We constructed a fusion gene encoding a protein composed of the alanine-rich region of PAg (PAgA) and the glucan-binding domain (GB) of GTF-I, which catalyzes the synthesis of water-insoluble glucan in S. sobrinus. The fusion protein PAgA-GB was purified from cell extracts of Escherichia coli harboring the fusion gene, and antibodies against the fusion protein were prepared in rabbits. Results:, In the presence of sucrose, the antibody against PAgA-GB significantly inhibited the adhesion of both S. sobrinus MT8145 and Streptococcus mutans Xc to saliva-coated hydroxyapatite beads, and the inhibitory effect on S. sobrinus was stronger than that on S. mutans. In the absence of sucrose, the antibody against PAgA-GB significantly inhibited the adhesion of both S. sobrinus and S. mutans, however the inhibitory effect on S. sobrinus was unexpectedly weaker than that on S. mutans. A similar result was observed with the antibody against the intact recombinant PAg protein (rPAg), while the same antibody reacted more strongly against S. sobrinus than against S. mutans cells. Conclusion:, Taken together, these results show that the antibody against S. sobrinus GTF-I may be useful for effective inhibition of the sucrose-dependent adhesion of S. sobrinus. However, PAg of S. sobrinus may not function primarily as a receptor for acquired pellicles, and other cell surface proteins may be involved in the sucrose-independent adhesion of S. sobrinus. [source]