title: Antibody responses to Porphyromonas gingivalis hemagglutinin A and outer membrane protein in chronic periodontitis.
abstract: BACKGROUND
  Hemagglutinin and outer membrane protein (OMP) are major virulence factors associated with colonization of Porphyromonas gingivalis in the gingival crevice. The genes for the 200-kDa antigenic protein (200-kDa AP) and 40-kDa OMP of P. gingivalis have been successfully cloned. Additionally, the 200-kDa AP gene has been shown to constitute the hemagglutinin A (hagA) gene of P. gingivalis. Therefore, this study was constructed to evaluate the distributions and serum levels of immnoglobulin G (IgG) antibodies specific for 200-kDa AP and 40-kDa OMP in periodontitis patients.
  
  
  METHODS
  Fifty patients with chronic periodontitis and 59 controls without periodontal destruction were enrolled in this study. We cloned the genes for 200-kDa AP and 40-kDa OMP from P. gingivalis and constructed the purified recombinant proteins. Serum levels of IgG subclass antibodies specific for both recombinant 200-kDa and 40-kDa OMP were determined in patients and controls by an enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  The serum IgG subclass distribution for patients and controls was IgG1>IgG4>IgG2>IgG3 in the anti-200-kDa AP response, which was almost identical to that in the anti-40-kDa OMP response. The patient group showed significantly higher serum IgG responses to the 40-kDa OMP than the control group (P<0.01). In contrast, IgG subclass responses to the 200-kDa AP were not different between the patients and controls. Serum levels of antibodies reactive with both 200-kDa and 40-kDa proteins did not have a significant association with mean probing depth.
  
  
  CONCLUSIONS
  These results suggested that serum IgG responses against P. gingivalis OMP rather than the hagA may be more active in chronic periodontitis.
authors.affiliation: Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, and General Dentistry and Clinical Education Unit, Niigata University Medical and Dental Hospital, Niigata, Japan. kotetsuo@dent.niigata-u.ac.jp
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Susumu
authors.initials: S
authors.lastname: Kaneko
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Tahara
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Hayakawa
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Abiko
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Yoshie
mesh_terms: D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000096:biosynthesis* / Q000097:blood; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D016022:Case-Control Studies; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D037102:Lectins / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010518:Periodontitis / Q000276:immunology / Q000382:microbiology*; D016966:Porphyromonas gingivalis / Q000276:immunology*; D018709:Statistics, Nonparametric; D037521:Virulence Factors / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D007074:Immunoglobulin G; D037102:Lectins; D037521:Virulence Factors; C114923:hemagglutinin A, Porphyromonas gingivalis