title: Serum antibodies against the hemoglobin-binding domain (HA2) of Porphyromonas gingivalis.
abstract: BACKGROUND
  The hemoglobin-binding domain (HA2) of the Porphyromonasgingivalis gingipains and hemagglutinins strongly binds hemoglobin and hemin and is thought to play a key role in acquisition of this essential metabolite by the microorganism.
  
  
  METHODS
  In this report, we partially characterized human anti-HA2 humoral antibodies and their relationship to periodontal disease in an analysis of titer and function.
  
  
  RESULTS
  Overall, serum anti-HA2 antibodies were relatively low and dominated by the immunoglobulin M (IgM) isotype. Pre-therapy titers had a direct association with periodontal health. Levels of P. gingivalis in the plaque were directly related to pre-therapy anti-HA2 IgG levels, and were an important covariant in a significant direct relationship between pre- and post-therapy anti-HA2 titers. Post-therapy anti-HA2 IgG antibody titers were directly related to the capacity of serum IgG fractions to neutralize hemoglobin binding by Lys-gingipain (Kgp). Further, lower levels of neutralizing activity post-therapy were directly related to severe periodontitis within the patient cohort.
  
  
  CONCLUSIONS
  These data suggest that anti-HA2 IgG antibodies correspond directly with periodontal health, possibly through their ability to neutralize P. gingivalis hemoglobin capture. The data also suggest that inadvertent or therapeutic inoculation of P. gingivalis in the plaque may contribute to generation of neutralizing anti-HA2 IgG and improvement of periodontal prognosis.
authors.affiliation: Nova Southeastern University, NSU Dental, 3200 S. University Drive, Fort Lauderdale, FL, USA. adecarlo@nova.edu
authors.forename: Arthur A
authors.initials: AA
authors.lastname: DeCarlo
authors.forename: Mangala
authors.initials: M
authors.lastname: Nadkarni
authors.forename: Mayuri
authors.initials: M
authors.lastname: Paramaesvaran
authors.forename: Peter W
authors.initials: PW
authors.lastname: Yun
authors.forename: Charles A
authors.initials: CA
authors.lastname: Collyer
authors.forename: Neil
authors.initials: N
authors.lastname: Hunter
mesh_terms: D018829:Adhesins, Bacterial / Q000276:immunology; D000907:Antibodies, Bacterial / Q000097:blood*; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000276:immunology*; D015331:Cohort Studies; D003546:Cysteine Endopeptidases / Q000276:immunology; D000080867:Gingipain Cysteine Endopeptidases; D006388:Hemagglutinins / Q000276:immunology; D006427:Hemin / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007132:Immunoglobulin Isotypes / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008875:Middle Aged; D010518:Periodontitis / Q000276:immunology / Q000382:microbiology / Q000628:therapy; D016966:Porphyromonas gingivalis / Q000276:immunology* / Q000472:pathogenicity; D011379:Prognosis; D011485:Protein Binding; D014774:Virulence
chemical_list: D018829:Adhesins, Bacterial; D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D002352:Carrier Proteins; D000080867:Gingipain Cysteine Endopeptidases; D006388:Hemagglutinins; D006454:Hemoglobins; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D007075:Immunoglobulin M; C017206:hemoglobin-binding protein, bacteria; D006427:Hemin; D003546:Cysteine Endopeptidases