Association of fibronectin with hypogalactosylated immunoglobulin G in gingival crevicular fluid in periodontitis.
BACKGROUND
Fibronectin (FN) can bind to immunoglobulins (Ig), influencing both the normal clearance and abnormal deposition of circulating immune complexes. This study focuses on the possible interaction between FN and IgG present in gingival crevicular fluid (GCF) of periodontitis patients and periodontally healthy controls, with the aim to determine whether such interaction may be connected with the glycosylation profile of IgG and, thus, consequentional in accumulation of proinflammatory IgG in periodontal pockets.


METHODS
The study included 30 patients with initial or advanced periodontitis, and 13 periodontally healthy subjects. GCF IgG was purified and analyzed for the presence of FN and its fragments and for galactose expression.


RESULTS
IgG isolated from GCF contained FN, which was bound to the IgG heavy chains. IgG from GCF of advanced periodontitis patients contained high levels of hypogalactosylated IgG, and bound more FN than IgG from GCF of the other two groups, which contained low levels of this glycoform. FN was in a degraded form in GCF from all studied patients, and a fragment of 48- to 53-kDa molecular mass seemed to be the sole one linked to IgG.


CONCLUSIONS
IgG and the FN fragment of 48 to 53 kDa in GCF of periodontitis patients and periodontally healthy subjects are physically connected. This fragment was linked to the heavy chains of IgG and the reaction seemed to be particularly intensive with IgG from advanced periodontitis, which contained significantly less galactose in its sugar chains.
Brajović
Gavrilo
G
School of Dentistry, University of Belgrade, Belgrade, Serbia.
Stefanović
Gordana
G
Ilić
Vesna
V
Petrović
Sonja
S
Stefanović
Neda
N
Nikolić-Jakoba
Nataša
N
Milosević-Jovcić
Nadezda
N
D000328:Adult; D001421:Bacteria, Anaerobic / Q000302:isolation & purification; D016022:Case-Control Studies; D003773:Dental Plaque / Q000382:microbiology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005353:Fibronectins / Q000032:analysis / Q000378:metabolism*; D005690:Galactose / Q000096:biosynthesis*; D005883:Gingival Crevicular Fluid / Q000276:immunology*; D006031:Glycosylation; D006090:Gram-Negative Bacteria / Q000302:isolation & purification; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D007143:Immunoglobulin Heavy Chains; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010518:Periodontitis / Q000276:immunology* / Q000378:metabolism*; D055815:Young Adult
D005353:Fibronectins; D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; D005690:Galactose