Human serum antibodies recognize Treponema denticola Msp and PrtP protease complex proteins.
OBJECTIVE
Treponema denticola outer membrane proteins are postulated to have key roles in microbe-host interactions in periodontitis. Because there are no reports of in vivo expression of these putative virulence factors, we examined several T. denticola strains to determine whether sera from human subjects recognized specific T. denticola outer membrane proteins.


METHODS
Soluble extracts were prepared from exponential phase cultures of T. denticola strains representing three serotypes, from defined T. denticola mutants defective in Msp (major surface protein) or PrtP lipoprotein protease complex (CTLP; dentilisin), and Escherichia coli strains expressing distinctly different T. denticola Msp. Extracts were subjected to Western immunoassays using archived human serum samples.


RESULTS
Human serum antibodies (immunoglobulin G class) recognized multiple protein bands in T. denticola strains. In the parent strain ATCC 35405, these included bands at 72-, 53-, 40-, and 30-kDa. Bands corresponding to Msp and the PrtP protease complex proteins were absent in isogenic msp and protease complex mutants, respectively. Individual human sera showed specificity for one or more Msp types.


CONCLUSIONS
This is the first definitive report of human serum antibody responses to specific T. denticola antigens. T. denticola Msp and the proteins comprising the PrtP lipoprotein protease complex are expressed in vivo and are immunogenic in humans. Human antibody recognition of Msp exhibits strain specificity and is consistent with strain serotyping. These results demonstrate the utility of T. denticola isogenic mutants in characterizing host immune responses to periodontal pathogens.
Capone
R
R
Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, MI, USA.
Wang
H T
HT
Ning
Y
Y
Sweier
D G
DG
Lopatin
D E
DE
Fenno
J C
JC
D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D000942:Antigens, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D015153:Blotting, Western; D002918:Chymotrypsin / Q000276:immunology*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000502:physiology; D010447:Peptide Hydrolases; D018272:Porins / Q000276:immunology*; D048373:Treponema denticola / Q000737:chemistry* / Q000276:immunology*; D037521:Virulence Factors
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D007074:Immunoglobulin G; D018272:Porins; D037521:Virulence Factors; C099361:major outer sheath protein, Treponema; D010447:Peptide Hydrolases; C102570:dentilisin; D002918:Chymotrypsin