title: Gingipain-specific IgG in the sera of patients with periodontal disease is necessary for opsonophagocytosis of Porphyromonas gingivalis.
abstract: BACKGROUND
  Porphyromonas gingivalis is a primary etiologic agent of generalized aggressive periodontitis (GAgP), and gingipains, a group of cysteine proteinases, are critical virulence factors expressed by this organism. GAgP patients develop specific antibodies to gingipains; however, the function of these antibodies in the clearance of P. gingivalis infection is poorly understood.
  
  
  METHODS
  In this study, we defined the levels of gingipain-specific antibodies in GAgP patient sera and examined the ability of gingipain-specific antibodies to facilitate opsonophagocytosis of P. gingivalis by human polymorphonuclear leukocytes (PMNs) using a fluorescent phagocytosis assay.
  
  
  RESULTS
  GAgP patient sera possessed elevated levels of P. gingivalis-, arginine-gingipain (Rgp)A-, RgpB-, and lysine-gingipain (Kgp)-specific IgG (Kgp > RgpA > P. gingivalis > RgpB). Adsorption of GAgP sera with P. gingivalis whole organisms, RgpA, RgpB, and Kgp conjugated to sepharose beads reduced opsonophagocytosis of P. gingivalis by PMNs.
  
  
  CONCLUSIONS
  Our studies demonstrate that GAgP patient sera possess elevated levels of P. gingivalis- and gingipain-specific IgG. Furthermore, we show that gingipain antibodies promote uptake of P. gingivalis by PMNs, and our data suggest that gingipain-specific antibodies may be important for the control of P. gingivalis infections.
authors.affiliation: Department of Medicine, Section of Infectious Diseases, Boston University Medical School, Boston, MA, USA. frank.gibson@bmc.org
authors.forename: Frank C
authors.initials: FC
authors.lastname: Gibson
authors.forename: Juan
authors.initials: J
authors.lastname: Savelli
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Van Dyke
authors.forename: Caroline Attardo
authors.initials: CA
authors.lastname: Genco
mesh_terms: D018829:Adhesins, Bacterial / Q000276:immunology*; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D016022:Case-Control Studies; D003546:Cysteine Endopeptidases / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D000080867:Gingipain Cysteine Endopeptidases; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D009504:Neutrophils / Q000502:physiology; D009895:Opsonin Proteins / Q000097:blood; D010518:Periodontitis / Q000097:blood / Q000276:immunology* / Q000382:microbiology; D010587:Phagocytosis / Q000502:physiology*; D016966:Porphyromonas gingivalis / Q000201:enzymology / Q000276:immunology*
chemical_list: D018829:Adhesins, Bacterial; D000907:Antibodies, Bacterial; D000080867:Gingipain Cysteine Endopeptidases; D007074:Immunoglobulin G; D009895:Opsonin Proteins; D003546:Cysteine Endopeptidases