title: Serum antibody titers to Bacteroides forsythus in elderly subjects with gingivitis or periodontitis.
abstract: BACKGROUND
  The risks for periodontal disease appear to increase with age.
  
  
  OBJECTIVE
  To determine associations between clinical findings, the presence of specific bacteria in periodontal pockets, and serum antibody titers. 10 older subjects (mean age=73.0 years SD+/-4.9) with confirmed gingivitis only (gingivitis group) and 10 subjects with periodontitis (mean age: 76.1 years, SD+/-10.4) (periodontitis group) were studied.
  
  
  RESULTS
  The mean group differences for probing depth and clinical attachment levels were 4.1 mm and 5.6 mm, respectively, and were significantly different (p<0.001). Both groups had high plaque scores (>60% surfaces with plaque). DNA probes demonstrated that B. forsythus was present in 8/10 samples from the periodontitis group and in 7/10 samples from the gingivitis group. The B. forsythus isolates studied were found in four of the subjects with periodontitis and from 2 of the subjects with gingivitis. Serum antibody titers to 6 ribotypes of B. forsythus were studied. Western blots, gradient gels, and pulsed field gel electrophoresis concurrently demonstrated that the B. forsythus isolates were genotypically, and phenotypically unique for each subject. Antibody titers to two selected B. forsythus isolates were significantly higher in the periodontitis group (p<0.01, Mann-Whitney test). The study confirmed that antibody serum titers to the six different ribotypes of B. forsythus varied greatly between older individuals with gingivitis or periodontitis. Not all strains of B. forsythus elicited higher titers in periodontitis affected subjects.
  
  
  CONCLUSIONS
  The results of the present study suggest genotype variation of B. forsythus that is unique to the individual and that serotype variation can be expected. It is possible that B. forsythus under specific host conditions can modulate surface antigen factors to evade the host immune response.
authors.affiliation: Department of Periodontics, University of Washington, Seattle 98195, USA. rper@u.washington.edu
authors.forename: G R
authors.initials: GR
authors.lastname: Persson
authors.forename: B
authors.initials: B
authors.lastname: Schlegel-Bregenzer
authors.forename: W O
authors.initials: WO
authors.lastname: Chung
authors.forename: L
authors.initials: L
authors.lastname: Houston
authors.forename: T
authors.initials: T
authors.lastname: Oswald
authors.forename: M C
authors.initials: MC
authors.lastname: Roberts
mesh_terms: D000367:Age Factors; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood*; D001439:Bacteroides / Q000235:genetics / Q000472:pathogenicity*; D015153:Blotting, Western; D016521:Electrophoresis, Gel, Pulsed-Field; D004591:Electrophoresis, Polyacrylamide Gel; D014644:Genetic Variation; D005891:Gingivitis / Q000097:blood / Q000382:microbiology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D010518:Periodontitis / Q000097:blood / Q000382:microbiology*; D021521:Ribotyping; D018709:Statistics, Nonparametric; D014774:Virulence
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G