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Periodontal ligament-associated protein 1 (PLAP-1), also known as Asporin, is an extracellular matrix protein expressed in the periodontal ligament and plays a crucial role in periodontal tissue homeostasis. Our previous research demonstrated that PLAP-1 may inhibit TLR2/4-mediated inflammatory responses, thereby exerting a protective function against periodontitis. However, the precise roles of PLAP-1 in the periodontal ligament (PDL) and its relationship to periodontitis have not been fully explored. In this study, we employed PLAP-1 knockout mice to investigate its roles and contributions to PDL tissue and function in a ligature-induced periodontitis model. Mandibular bone samples were collected from 10-week-old male C57BL/6 (WT) and PLAP-1 knockout (KO) mice. These samples were analyzed through micro-computed tomography (μCT) scanning, hematoxylin and eosin (HE) staining, picrosirius red staining, and fluorescence immunostaining using antibodies targeting extracellular matrix proteins. Additionally, the structure of the PDL collagen fibrils was examined using transmission electron microscopy (TEM). We also conducted tooth extraction and ligature-induced periodontitis models using both wild-type and PLAP-1 KO mice. PLAP-1 KO mice did not exhibit any changes in alveolar bone resorption up to the age of 10 weeks, but they did display an enlarged PDL space, as confirmed by μCT and histological analyses. Fluorescence immunostaining revealed increased expression of extracellular matrix proteins, including Col3, BGN, and DCN, in the PDL tissues of PLAP-1 KO mice. TEM analysis demonstrated an increase in collagen diameter within the PDL of PLAP-1 KO mice. In line with these findings, the maximum stress required for tooth extraction was significantly lower in PLAP-1 KO mice in the tooth extraction model compared to WT mice (13.89 N ± 1.34 and 16.51 N ± 1.31, respectively). In the ligature-induced periodontitis model, PLAP-1 knockout resulted in highly severe alveolar bone resorption, with a higher number of collagen fiber bundle tears and significantly more osteoclasts in the periodontium. Our results demonstrate that mice lacking PLAP-1/Asporin show alteration of periodontal ligament structures and acceleration of bone loss in periodontitis. This underscores the significant role of PLAP-1 in maintaining collagen fibrils in the PDL and suggests the potential of PLAP-1 as a therapeutic target for periodontal diseases.

Fibroblast growth factor-2 (FGF-2) stimulates periodontal regeneration by a broad spectrum of effects on periodontal ligament (PDL) cells, such as proliferation, migration, and production of extracellular matrix. A critical factor in the success of periodontal regeneration is the rapid resolution of inflammatory responses in the tissue. We explored an anti-inflammatory effect of FGF-2 during periodontal regeneration and healing. We found that FGF-2 on mouse periodontal ligament cells (MPDL22) markedly downregulated CD40 expression, a key player of inflammation. In addition, FGF-2 inhibited CD40 signaling by the non-canonical nuclear factor-kappa B2 (NFκB2) pathway, resulting in decreased production of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), which have the potential to recruit immune cells to inflamed sites. Furthermore, in vivo treatment of FGF-2 enhanced healing of skin wounds by counteracting the CD40-mediated inflammation. These results reveal that FGF-2 has an important function as a negative regulator of inflammation during periodontal regeneration and healing., (© 2018 Wiley Periodicals, Inc.)

Background: Antimicrobial proteins are abundant in saliva. The purpose of this study was to determine and compare the amounts of two types of antibacterial protein, cystatin and lysozyme, in saliva between healthy persons and subjects with periodontitis., Methods: Forty subjects with periodontitis visiting Tokyo Dental College Chiba Hospital, Chiba, Japan, and 27 healthy persons were evaluated. Whole saliva was collected by requiring all subjects to expectorate into a sterile tube. Salivary levels of cystatin SA, cystatin C, and lysozyme were determined by enzyme-linked immunosorbent assay or immunoblot assay., Results: Cystatin SA levels in saliva from the periodontally diseased group showed a mean value of 0.063 +/- 0.026 mg/ml, statistically lower than that in the healthy group (P <0.05). The average cystatin C level in the periodontally diseased group was 2.27 +/- 1.20 ng/ml, markedly lower than that in the healthy group (3.79 +/- 1.28 ng/ml; P <0.05). Average lysozyme levels in the periodontitis and healthy groups were 16.75 +/- 15.31 microg/ml and 30.03 +/- 15.03 microg/ml, respectively. The lysozyme level in the periodontitis group was significantly lower than in the healthy group (P <0.05)., Conclusion: Specific monoclonal antibodies are useful for the detection of family 2 cystatins in saliva samples, and the amount of antibacterial protein in saliva offers a potential indicator of the risk for periodontitis.

Treponema denticola, a major pathogen of periodontitis, has also been detected in the lesions of atherosclerosis. The aim of this study was to investigate induction of chemokine production in human umbilical vein endothelial cells (HUVECs) by T. denticola and determine whether those chemokines were degraded by a protease, dentilisin. T. denticola ATCC35405 or dentilisin-deficient mutant K1 were added to HUVECs and levels of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) in the culture supernatants were determined by enzyme-linked immunosorbent assay. T. denticola ATCC35405 induced production of IL-8 in a time-dependent manner, with both production of IL-8 and expression of IL-8 mRNA showing higher levels than with exposure to dentilisin-deficient mutant K1. Although exposure to ATCC35405 induced expression of MCP-1 mRNA in the HUVECs, MCP-1 levels were remained similar to that in unstimulated cells. IL-8 and MCP-1 showed partial hydrolysis with exposure to T. denticola ATCC35405, but not with T. denticola K1. These results suggest that T. denticola can evade host defense mechanisms by modulating production of IL-8 and MCP-1, and that this play a role in the development of chronic infections such as periodontitis. The association of T. denticola infection to atherosclerosis was also discussed based on the present study.

Periodontitis is a common inflammatory disease causing destruction of periodontal tissues. It is a multifactor disease involving genetic factors and oral environmental factors. To determine genetic risk factors associated with aggressive periodontitis or severe chronic periodontitis, single nucleotide polymorphisms (SNPs) in multiple candidate genes were investigated in Japanese. We studied 134 patients with aggressive periodontitis, 117 patients with severe chronic periodontitis, and 125 healthy volunteers without periodontitis, under case-control setting, and 310 SNPs in 125 candidate genes were genotyped. Association evaluation by Fisher's exact test (p < 0.01) revealed statistically significant SNPs in multiple genes, not only in inflammatory mediators (IL6ST and PTGDS, associated with aggressive periodontitis; and CTSD, associated with severe chronic periodontitis), but also in structural factors of periodontal tissues (COL4A1, COL1A1, and KRT23, associated with aggressive periodontitis; and HSPG2, COL17A1, and EGF, associated with severe chronic periodontitis). These appear to be good candidates as genetic factors for future study.

Background: Arginine- and lysine-specific cysteine proteinases (arg-gingipain: Rgp, lys-gingipain: Kgp) are major virulence factors of Porphyromonas gingivalis. Recent reports have suggested that antibodies against gingipains can play a protective role against infection by P. gingivalis. The purpose of this study was to evaluate the IgG responses of patients with periodontitis to functional domains of gingipains., Methods: A group of 29 periodontitis patients and 10 periodontally healthy subjects (control group) were recruited into this study. We prepared three recombinant fragments of rgp A (catalytic domain; r-Rgp CAT) and two hemagglutinin domains (r-Rgp 44, and r-Rgps 15-27) corresponding to amino acid residues 228 to 719, 720 to 1136, and 1137 to 1704, respectively. One fragment of the Kgp catalytic domain (r-Kgp CAT) corresponding to amino acid residues 229 to 737 and expressed in Escherichia coli was also used. IgG antibody levels to these recombinant proteins in sera from the subjects were determined by an enzyme-linked immunosorbent assay (ELISA)., Results: We found that IgG levels against r-Rgp 44 and r-Rgps 15-27 in sera obtained from the patients were significantly higher than those in the healthy group (P<0.01). In contrast, no significant differences in IgG levels against r-Rgp CAT and r-Kgp CAT were found between the control and patient groups. The IgG responses to P. gingivalis sonic extracts, r-Rgp 44 and r-Rgps 15-27, were related to probing depth in sera from patients, but those to r-Rgp CAT and r-Kgp CAT were not., Conclusion: The present findings suggest that the low responsiveness of IgG antibody against the catalytic domains of gingipain, r-Rgp CAT, and r-Kgp CAT is a key factor in infection by P. gingivalis.

Background: Porphyromonas gingivalis is one of the major microbial pathogens associated with chronic periodontitis. To eradicate such pathogens by periodontal therapy, it is essential to clarify the source of infection. Recent findings suggest that the genotype of the fimbriae is one of the important factors in infection by P. gingivalis. The objectives of the present study were to investigate the transmission of P. gingivalis between spouses and to determine the relationship between P. gingivalis fimA type and colonization., Methods: A total of 14 couples were selected to investigate the transmission of P. gingivalis and its association with the fimA types. To examine the distribution of fimA type in the general population, 32 subgingival plaque samples from 47 patients with periodontitis were also tested. The transmission of P. gingivalis strains was determined by using pulsed field gel electrophoresis (PFGE). P. gingivalis strains isolated from the couples and subgingival dental plaque samples were studied for fimA classification., Results: The PFGE patterns of P. gingivalis strains from matched husbands and wives were identical for six of the 14 couples. In five of these six couples (83.3%), P. gingivalis strains harboring the type II fimA gene were present. The proportion of type II fimA in the strains isolated from couples with probable intrafamilial transmission was significantly higher than that in patients with periodontitis or in the group of samples isolated from one member of a couple., Conclusion: This study suggests that fimA type II, even though widely distributed in patients with periodontitis, may be an important factor in the transmission of P. gingivalis between spouses.

Campylobacter rectus, a gram-negative, microaerophilic, and motile bacterium, has been proposed to play a pathogenic role in human periodontitis. Surface components, such as the flagellum, surface layer (S-layer), and cytotoxin, have been reported as possible virulence factors of the microorganism. In the present study, monoclonal antibodies against surface components of this bacterium were produced to detect and investigate the pathogenic potential of C. rectus in periodontitis. Two monoclonal antibodies, designated CRT-1 and CRT-2, recognized a peculiar 150 kDa S-layer protein by immunoblot analysis. The CRT-2 antibody reacted to all C. rectus strains tested, except for the S-layer negative strain of the species [C. rectus ATCC 33238 S-layer (-) strain]. The CRT-3 antibody reacted to a 60-kDa protein in C. rectus and also cross-reacted with Campylobacter showae ATCC 51164 and CCUG 11641 strains. Using the dot-blot method, we were able to detect C. rectus using the CRT-2 antibody when as few as 103 organisms were present in a subgingival dental plaque sample. Detection of C. rectus in plaque samples correlated significantly with clinical findings such as probing depth (P < 0.001), bleeding on probing (P < 0.001), and gingival index (P < 0.001). These findings indicate that infection by C. rectus may be an important indicator of periodontal disease status.

Periodontal breakdown in periodontitis is exacerbated by pro-inflammatory responses of periodontal stromal cells such as periodontal ligament fibroblasts (PDLFs). Procyanidin B2 (PB2) is a ligand of the peroxisome proliferator-activated receptor (PPARγ). Herein, we investigated the expression of PPARγ isoforms in PDLFs and periodontal tissue, and examined the effects of PB2 on PPARγ isoform-dependent antiinflammatory responses. PPARγ isoforms were examined by PCR. PPARγ isoform-dependent inflammatory functions and anti-inflammatory effects of PB2 in PDLFs were evaluated based on IL-6 expression. Co-immunoprecipitation analysis of fixed chromatin-tethered protein (CoIPfctp) was conducted to investigate the association of each PPARγ isoform with the NF-κB-transcriptional complex. The effects of PB2 on periodontitis progression were evaluated using a ligature-induced murine periodontitis model. Three isoforms of PPARγ were expressed in PDLFs and periodontal tissues, consisting of the main full-length isoform (PPARγ) and two dominant negative isoforms that lack the ligand binding domain, namely the ubiquitously-expressed isoform (PPARγ-UBI) and unknown isoform (PPARγ-PDL). PPARγ and PPARγ-UBI were predominantly expressed. CoIP-fctp revealed that PPARγ-UBI was selectively associated with NF-κB p65, a key transcriptional factor of IL-6 expression. PB2 suppressed LPS-induced-IL-6 expression exacerbated by the over-expression of PPARγ-UBI. In the murine periodontitis model, topical application of PB2 significantly mitigated alveolar bone loss. These results suggest that the anti-inflammatory effects of PB2 in periodontal tissues/cells are distinct, and these effects arise from the inhibition of PPARγ-UBI; hence, the application of PB2 and modification of the splicing event in three PPARγ isoforms have therapeutic potential for preventing periodontitis. [ABSTRACT FROM AUTHOR]

Periodontitis is characterized by irreversible destruction of periodontal tissue. At present, the accepted etiology of periodontitis is based on a three-factor theory including pathogenic bacteria, host factors, and acquired factors. Periodontitis development usually takes a decade or longer and is therefore called chronic periodontitis (CP). To search for genetic factors associated with CP, several genome-wide association study (GWAS) analyses were conducted; however, polymorphisms associated with CP have not been identified. Epigenetics, on the other hand, involves acquired transcriptional regulatory mechanisms due to reversibly altered chromatin accessibility. Epigenetic status is a condition specific to each tissue and cell, mostly determined by the responses of host cells to stimulations by local factors, like bacterial inflammation, and systemic factors such as nutrition status, metabolic diseases, and health conditions. Significantly, epigenetic status has been linked with the onset and progression of several acquired diseases. Thus, epigenetic factors in periodontal tissues are attractive targets for periodontitis diagnosis and treatments. In this review, we introduce accumulating evidence to reveal the epigenetic background effects related to periodontitis caused by genetic factors, systemic diseases, and local environmental factors, such as smoking, and clarify the underlying mechanisms by which epigenetic alteration influences the susceptibility of periodontitis. [ABSTRACT FROM AUTHOR]

Loeys–Dietz syndrome (LDS) is a syndromic connective tissue disorder caused by a heterozygous missense mutation in genes that encode transforming growth factor (TGF)-β receptor (TGFBR) 1 and 2. We encountered a patient with LDS, who had severe periodontal tissue destruction indicative of aggressive periodontitis. The patient had a missense mutation in the glycine and serine-rich domain of TGFBR1 exon 3. This G-to-T mutation at base 563 converted glycine to valine. We established an LDS model knock-in mouse that recapitulated the LDS phenotype. Homozygosity of the mutation caused embryonic lethality and heterozygous knock-in mice showed distorted and ruptured elastic fibers in the aorta at 24 weeks of age and died earlier than wildtype (WT) mice. We stimulated mouse embryonic fibroblasts (MEFs) from the knock-in mouse with TGF-β and examined their responses. The knock-in MEFs showed downregulated Serpine 1 mRNA expression and phosphorylation of Smad2 to TGF-β compared with WT MEFs. To clarify the influence of TGF-β signaling abnormalities on the pathogenesis or progression of periodontitis, we performed pathomolecular analysis of the knock-in mouse. There were no structural differences in periodontal tissues between WT and LDS model mice at 6 or 24 weeks of age. Micro-computed tomography revealed no significant difference in alveolar bone resorption between WT and knock-in mice at 6 or 24 weeks of age. However, TGF-β-related gene expression was increased significantly in periodontal tissues of the knock-in mouse compared with WT mice. Next, we assessed a mouse periodontitis model in which periodontal bone loss was induced by oral inoculation with the bacterial strain Porphyromonas gingivalis W83. After inoculation, we collected alveolar bone and carried out morphometric analysis. P. gingivalis -induced alveolar bone loss was significantly greater in LDS model mice than in WT mice. Peritoneal macrophages isolated from Tgfbr1 G 188V/+ mice showed upregulation of inflammatory cytokine mRNA expression induced by P. gingivalis lipopolysaccharide compared with WT macrophages. In this study, we established an LDS mouse model and demonstrated that LDS model mice had elevated susceptibility to P. gingivalis -induced periodontitis, probably through TGF-β signal dysfunction. This suggests that TGF-β signaling abnormalities accelerate the pathogenesis or progression of periodontitis. [ABSTRACT FROM AUTHOR]

Periodontitis is an inflammatory disease causing loss of tooth-supporting periodontal tissue. Disease susceptibility to the rapidly progressive form of periodontitis, aggressive periodontitis (AgP), appears to be influenced by genetic risk factors. To identify these in a Japanese population, we performed whole exome sequencing of 41 unrelated generalized or localized AgP patients. We found that AgP is putatively associated with single nucleotide polymorphism (SNP) rs536714306 in the G-protein coupled receptor 126 gene, GPR126 [c.3086 G>A (p.Arg1029Gln)]. Since GPR126 activates the cAMP/PKA signaling pathway, we performed cAMP ELISA analysis of cAMP concentrations, and found that rs536714306 impaired the signal transactivation of GPR126. Moreover, transfection of human periodontal ligament (HPDL) cells with wild-type or mutant GPR126 containing rs536714306 showed that wild-type GPR126 significantly increased the mRNA expression of bone sialoprotein, osteopontin, and Runx2 genes, while mutant GPR126 had no effect on the expression of these calcification-related genes. The increase in expression of these genes was through the GPR126-induced increase of bone morphogenic protein-2, inhibitor of DNA binding (ID) 2, and ID4 expression. These data indicate that GPR126 might be important in maintaining the homeostasis of periodontal ligament tissues through regulating the cytodifferentiation of HPDL cells. The GPR126 SNP rs536714306 negatively influences this homeostasis, leading to the development of AgP, suggesting that it is a candidate genetic risk factor for AgP in the Japanese population. [ABSTRACT FROM AUTHOR]

Cigarette smoking is a major lifestyle-related risk factor for periodontal diseases. However, the pathophysiological role of cigarette smoking in periodontal disease has yet to be fully elucidated. Here we report that the systemic administration of cigarette smoke condensate or nicotine, which is the major ingredient of cigarette smoke, augmented alveolar bone loss. Concomitantly, the number of osteoclasts in periodontal tissues increased and the expression of receptor activator of nuclear factor κB ligand was upregulated at the ligated side in mice with periodontitis. Nicotine also attenuated alveolar bone repair after ligature removal. These observations highlight the destruction of periodontal tissue by smoking and the unfavorable clinical course of periodontal disease in patients with a cigarette smoking habit. The present study demonstrates that periodontal disease models are useful for elucidating the pathogenesis of cigarette smoking-related periodontal diseases. [ABSTRACT FROM AUTHOR]

Tobacco smoking is a significant risk factor for periodontal diseases. Nicotine, one of the most studied constituents in cigarette smoke, is thought to modify immune responses. Dendritic cells ( DCs), which are key mediators between innate and adaptive immunity, stimulate naive T cells to differentiate to effector T-cell subsets that may be actively involved in the immunopathogenesis of periodontal diseases. In this study, we evaluated the effects of nicotine and lipopolysaccharide ( LPS) from Porphyromonas gingivalis, alone and in combination, on the functions of human monocyte-derived DCs to elucidate the mechanism of tissue destruction of smoking-associated periodontal diseases. P. gingivalis LPS-stimulated DCs differentiated with nicotine ( Ni DCs) induced lower T-cell proliferation and human leukocyte antigen ( HLA)- DR expression, but elevated expression of programmed cell death ligand 1. Additionally, Ni DCs impaired interferon- γ production but maintained interleukin ( IL)-5 and IL-10 production in co-cultured T cells. Furthermore, Ni DCs produced lower levels of proinflammatory cytokines compared with DCs differentiated in the absence of nicotine. Interestingly, Ni DCs preferentially produced the T helper 2 ( Th2)-type chemokines macrophage chemotactic protein-1 and macrophage-derived chemokine. These results suggest that the presence of nicotine during differentiation of DCs modulates the immunoregulatory functions of P. gingivalis LPS-stimulated DCs. [ABSTRACT FROM AUTHOR]

Background: Smoking is a risk factor for periodontitis. To clarify the contribution of smoking to periodontitis, it is essential to assess the relationship between smoking and the subgingival microflora. The aim of this study was to gain an insight into the influence of smoking on the microflora of Japanese patients with periodontitis. Methods: Sixty-seven Japanese patients with chronic periodontitis (19 to 83 years old, 23 women and 44 men) were enrolled in the present study. They consisted of 30 smokers and 37 non-smokers. Periodontal parameters including probing pocket depth (PPD) and bleeding on probing (BOP) and oral hygiene status were recorded. Detection of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Fusobacterium nucleatum/periodonticum, Treponema denticola and Campylobacter rectus in subgingival plaque samples was performed by polymerase chain reaction. Association between the detection of periodontopathic bacteria and smoking status was analyzed by multiple logistic regression analysis and chi-square test. Results: A statistically significant association was found between having a PPD ≥ 4 mm and detection of T. denticola, P. intermedia, T. forsythia, or C. rectus, with odds ratios ranging from 2.17 to 3.54. A significant association was noted between BOP and the detection of C. rectus or P. intermedia, and smoking, with odds ratios ranging from 1.99 to 5.62. Prevalence of C. rectus was higher in smokers than non-smokers, whereas that of A. actinomycetemcomitans was lower in smokers. Conclusions: Within limits, the analysis of the subgingival microbial flora in smokers and non-smokers with chronic periodontitis suggests a relevant association between smoking and colonization by the specific periodontal pathogens including C. rectus. [ABSTRACT FROM AUTHOR]

Periodontal disease, for which smoking is a known risk factor, is infectious, and is associated with oral biofilm. Cytokines mediate and regulate immune and inflammatory responses. Lipopolysaccharide produced by periodontopathic bacteria plays a role in the progression of periodontitis. The effect of nicotine on cytokine production in mice was evaluated in this study. Nicotine (10 or 200 μg mouse−1) was administered intraperitoneally to 4-week-old female BALB/c mice, once a day, for 49 days. Control mice received injections of phosphate-buffered saline. Blood was collected from all mice and serum IL-6, IL-10, tumor necrosis factor (TNF)-α and IFN-γ levels were measured by an enzyme-linked immunosorbent assay on the 42nd day. IL-6, IL-10 and IFN-γ levels in the nicotine-treated mice were higher than those in the control mice. However, no differences were found in TNF-α levels between nicotine-treated and control mice. Lipopolysaccharide (20 μg mouse−1) purified from Aggregatibacter actinomycetemcomitans (formerly Actinobacillus actinomycetemcomitans) Y4 was administered intraperitoneally on the 49th day. A rapid increase in TNF-α was observed in the control mice at 2 h after administration of lipopolysaccharide. In contrast, no increase was noted in the nicotine-treated groups. Significantly higher levels of IFN-γ were seen in the 200 μg nicotine-treated mice at 2 h after administration of lipopolysaccharide ( P<0.05). The results showed that cytokine levels were influenced by nicotine in mice. [ABSTRACT FROM AUTHOR]

Background: The objective of the present study was to develop a rapid DNA probe method for the microbiological detection of periodontitis that can be used in dental clinics. By using the DNA probe, we also investigated the correlation between the occurrence of putative periodontopathic bacteria and clinical parameters. Methods: This rapid DNA probe method minimizes the use of a water bath for ordinary hybridization and washing in order to shorten the total reaction time. The detection process could be completed within 2 hours. In order to evaluate the clinical application of the DNA probe, subgingival plaque samples were taken from patients with periodontitis before initial therapy. After the therapy, the patients were microbiologically and clinically evaluated. Results: When the DNA probe method was compared with the culture method, the agreement was 88% for Porphyromonas gingivalis and 67% for Actinobacillus actinomycetemcomitans. A statistically significant association was found between the detection of P. gingivalis and probing depth, bleeding on probing (χ² test: P<0.001, P<0.05). A significant association was also shown between the detection of A. actinomycetemcomitans and probing depth in patients aged 35 or older (χ² test: P<0.001). The detection rate of A. actinomycetemcomitans was highest in teenagers. At shallow periodontal pocket sites (PD ≤3 mm) in teenagers, no P. gingivalis was found, while 22% of the sites harbored A. actinomycetemcomitans. After the therapy, the frequency of detection of P. gingivalis decreased significantly only in the clinically improved sites (χ² test: P<0.01). Conclusion: The rapid DNA probe method appears promising as an efficient tool for rapid clinical detection of periodontopathic bacteria. [ABSTRACT FROM AUTHOR]

THE PURPOSE OF THIS STUDY WAS TO EXAMINE avidity of immunoglobulin G (IgG) antibody for surface antigens of Porphyromonas gingivalis in sera from patients with adult periodontitis. The antigens used were whole cell antigens, lipopolysaccharides (LPS), and fimbriae of non-invasive P. gingivalis ATCC 33277 and invasive 16-1. Serum IgG titers for the P. gingivalis antigens were measured by enzyme-linked immunosorbent assay (ELISA) before and after periodontal initial preparation. IgG avidity was measured by diethylamine dissociation ELISA. IgG titers for the whole cell antigens of 16-1, LPS, and the fimbria antigens from both P. gingivalis strains were significantly higher in the patient group than those in the control group, whereas values for avidities were significantly lower in patient sera. Although we found a statistically significant decrease in the IgG titers of patients following initial preparation, avidities against the fimbria antigen of invasive 16-1 strain increased. The present study showed that IgG antibodies elicited in patients were different in their ability to respond to invasive P. gingivalis 16-1 and to non-invasive 33277. The patient sera with high IgG titers demonstrated low values for avidity, suggesting that IgG responses in patients play a limited role in colonization inhibition or elimination of P. gingivalis. The data indicate that periodontally healthy individuals may have highly functional antibodies which may protect against P. gingivalis colonization. Our findings suggest that the ability to produce functional antibodies in the patient group is lower than that in the periodontally healthy group, but the functional antibodies can be induced by the initial preparation. [ABSTRACT FROM AUTHOR]

Abstract: Treponema denticola is a dominant microorganism in human periodontal lesions. One of the major virulence factors of this microorganism is its chymotrypsin-like surface protease, dentilisin. The purpose of this study was to evaluate the effect of dentilisin on human polymorphonuclear leukocytes (PMNs). We used chemiluminescence to assess production of O2 − by PMNs against T. denticola ATCC 35405 and dentilisin-deficient mutant K1. T. denticola ATCC 35405 induced production of O2 −, whereas dentilisin-deficient K1 did not. We found that chymostatin, a protease inhibitor, strongly reduced the ability of T. denticola ATCC 35405 to induce production of, O2 −, whereas K1 was relatively unaffected. We also used Immunoblot and ELISA to evaluate the activation of complement by this microorganism in relation to PMNs. T. denticola ATCC 35405 hydrolyzed the α-chain of C3, producing iC3b. Furthermore, strain ATCC 35405 induced a larger release of MMP-9 from PMNs than strain K1. Dentilisin activated PMNs via complement pathways and may play a role in establishing periodontal lesions. [Copyright &y& Elsevier]