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.
OBJECTIVE
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.


CONCLUSIONS
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.
Kawato
T
T
Department of Oral Health Sciences, Nihon University School of Dentistry, Tokyo, Japan. kawato@dent.nihon-u.ne.jp
Yamashita
Y
Y
Katono
T
T
Kimura
A
A
Maeno
M
M
D000328:Adult; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology*; D001422:Bacterial Adhesion / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D017886:Durapatite / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D016695:Glycosyltransferases / Q000276:immunology*; D006801:Humans; D015151:Immunoblotting; D008565:Membrane Proteins / Q000276:immunology*; D011817:Rabbits; D011994:Recombinant Proteins; D012463:Saliva / Q000502:physiology; D013295:Streptococcus mutans / Q000276:immunology*; D016986:Streptococcus sobrinus / Q000276:immunology*; D013395:Sucrose / Q000494:pharmacology; D013499:Surface Properties
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001426:Bacterial Proteins; D008565:Membrane Proteins; C082103:PAg protein, Streptococcus sobrinus; D011994:Recombinant Proteins; C067118:GTF-I protein, Streptococcus; D013395:Sucrose; D017886:Durapatite; D016695:Glycosyltransferases