Cleavage of IgG1 in gingival crevicular fluid is associated with the presence of Porphyromonas gingivalis. (1st November 2012)

• Record Type: Journal Article
• Authors: Guentsch, A.; Hirsch, C.; Pfister, W.; Vincents, B.; Abrahamson, M.; Sroka, A.; Potempa, J.; Eick, S.
• Is Part Of: Journal of periodontal research. Volume 48:Number 4(2013:Aug.)
• Page Start: 458
• Page End: 465
• Publication Date: 2012-11-01
• Subjects: Periodontics -- Periodicals; 617.632
• DOI: 10.1111/jre.12027
• Languages: English
• ISSNs: 0022-3484

Abstract

<abstract abstract-type="main" id="jre12027-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="jre12027-sec-0001" sec-type="section"> <title>Background and Objectives</title> <p>Immunoglobulin (Ig) G1 plays an important role in the adaptive immune response. Kgp, a lysine‐specific cysteine protease from <italic>Porphyromonas gingivalis, </italic> specifically hydrolyses IgG1 heavy chains. The purpose of this study was to examine whether cleavage of IgG1 occurs in gingival crevicular fluid (GCF) <italic>in vivo</italic>, and whether there is any association with the presence of <italic>Porphyromonas gingivalis</italic> and other periodontopathogens.</p> </sec> <sec id="jre12027-sec-0002" sec-type="section"> <title>Material and Methods</title> <p>GCF was obtained from nine patients with aggressive periodontitis, nine with chronic periodontitis and five periodontally healthy individuals. The bacterial loads of <italic>Porphyromonas gingivalis</italic>, <italic> Aggregatibacter actinomycetemcomitans</italic>, <italic> Treponema denticola</italic>, <italic> Prevotella intermedia</italic> and <italic>Tannerella forsythia</italic> were analysed by real‐time polymerase chain reaction, and the presence and cleavage of IgG1 and IgG2 were determined using Western blotting. Kgp levels were measured by ELISA.</p> </sec> <sec id="jre12027-sec-0003" sec-type="section"> <title>Results</title> <p>Cleaved IgG1 was identified in the GCF from 67% of patients with aggressive periodontitis and in 44% of patients with chronic periodontitis. By contrast, no cleaved IgG1 was detectable in healthy controls. No degradation of IgG2 was detected in any of the samples, regardless of health status. <italic>Porphyromonas gingivalis</italic> was found in high numbers in all samples in which cleavage of IgG1 was detected (<italic>P</italic> < 0.001 compared with samples with no IgG cleavage). Furthermore, high numbers of <italic>Tannerella forsythia</italic> and <italic>Prevotella intermedia</italic> were also present in these samples. The level of Kgp in the GCF correlated with the load of <italic>Porphyromonas gingivalis</italic> (<italic>r</italic> = 0.425, <italic>P</italic> < 0.01). The presence of Kgp (range 0.07–10.98 ng/mL) was associated with proteolytic fragments of IgG1 (<italic>P</italic> < 0.001). However, cleaved IgG1 was also detected in samples with no detectable Kgp.</p> </sec> <sec id="jre12027-sec-0004" sec-type="section"> <title>Conclusion</title> <p>In patients with periodontitis, cleavage of IgG1 occurs <italic>in vivo</italic> and may suppress antibody‐dependent antibacterial activity in subgingival biofilms especially those colonized by <italic>Porphyromonas gingivalis</italic>.</p> </sec> </abstract>