Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0031099 (periodontitis)
 12,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The titre and avidity of IgG antibodies to Porphyromonas gingivalis whole cells and a 47 kDa cell surface protein were determined in serum samples taken from 20 subjects with adult periodontitis and 20 controls, matched for age, gender, ethnic origin and oral hygiene status. Antibody titres were measured by ELISA and antibody avidity was determined by a chaotrope-dissociation ELISA. Avidity was defined as the molarity of chaotrope required to reduce absorbance by 50% (ID50). The mean IgG antibody log titre to whole cells (8.29 vs. 6.92; p < 0.01) and to the 47 kDa antigen (7.61 vs. 6.77; p < 0.05) were higher in cases than in controls. Mean IgG antibody avidity to whole cells (4.59 vs. 2.47; p < 0.001) and to the surface protein (2.54 vs. 1.67; p < 0.001) were also higher in cases than in controls. In cases, IgG antibody titre was highly correlated with avidity for both whole cells (r = 0.878; p = < 0.001) and the 47 kDa protein (r = 0.683; p < 0.001). There was a weaker positive correlation between the titre and the avidity of antibody to whole cells (r = 0.591; p < 0.01) in the control population but antibody titre and avidity for the 47 kDa sonicate antigen were not correlated in the controls (r = 0.104). We conclude that many patients with adult periodontitis have effective humoral immunity to P. gingivalis. However, in up to half the patients with adult periodontitis, antibody titres and avidities were low and similar to control values, indicating either susceptibility due to poor host response or that disease is not associated with this particular pathogen.
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PMID:Increased titre and avidity of IgG antibodies to Porphyromonas gingivalis whole cells and a cell surface protein in subjects with adult periodontitis. 908 40

Periodontal disease is one of the most common inflammatory infectious diseases worldwide and it is associated with other syndromes, such as cardiovascular disease or rheumatoid arthritis. Recent advances in sequencing allowed for identification of novel periodontopathogens such as Gram-positive Filifactor alocis, but its virulence mechanisms remain largely unknown. We confirmed that F. alocis is a prevalent species in periodontitis patients, and we also observed strong correlation of this bacterium with clinical parameters, highlighting its role in the pathogenesis of the disease. Further, we found that preincubation of human serum with F. alocis resulted in abolished bactericidal activity and that F. alocis was surviving readily in full blood. We demonstrated that one of the key contributors to F. alocis complement resistance is a unique protein, FACIN (F. alocis complement inhibitor), which binds to C3, resulting in suppression of all complement pathways. Interestingly, FACIN is a nonclassical cell surface protein, a cytosolic enzyme acetylornithine transaminase, for which we now identified a moonlighting function. FACIN binds to C3 alone, but more importantly it also captures activated complement factor 3 within the complex with factor B, thereby locking in the convertase in an inactive state. Because of the indispensable role of alternative pathway convertase in amplifying complement cascades, its inhibition by FACIN results in a very potent downregulation of activated complement factor 3 opsonization on the pathogen surface, accompanied by reduction of downstream C5 cleavage.
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PMID:FACIN, a Double-Edged Sword of the Emerging Periodontal Pathogen Filifactor alocis: A Metabolic Enzyme Moonlighting as a Complement Inhibitor. 2763 63