Humoral immune responses to Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in adult periodontitis and rapidly progressive periodontitis

The role of acquired host immunity in periodontal diseases

The aim of this narrative review is to relate the contribution of European researchers to the complex topic of the host immune system in periodontal disease, focusing on acquired immunity. Other chapters in this volume will address the genetics and autoantibody responses and other forms of immunity to periodontal disease. While the contribution of European authors is the focus, global literature is included in this descriptive narrative for contextual clarity, albeit many with European co-authors. The topic is relatively intense and is thus broken down into sections outlined below, tackled as descriptive narratives to enhance understanding. Any attempt at a systematic or scoping review was quickly abandoned given the descriptive nature and marked variation of approach in almost all publications. Even the most uniform area of this acquired periodontal immunology literature, antibody responses to putative pathogens in periodontal diseases, falls short of common structures and common primary outcome variables one would need and expect in clinical studies, where randomized controlled clinical trials (RCTs) abound. Addressing 'the host's role' in immunity immediately requires a discussion of host susceptibility, which necessitates consideration of genetic studies (covered elsewhere in the volume and superficially covered here).

Orally Administered Probiotics Decrease Aggregatibacter actinomycetemcomitans but Not Other Periodontal Pathogenic Bacteria Counts in the Oral Cavity: A Systematic Review and Meta-Analysis

Introduction: At the initial part of the gastrointestinal tract, multiple tissues serve the normal function of food delivery. Periodontal structures are integral elements of these. When they deteriorate, it is extremely challenging to regenerate and reconstruct them. The conventional intervention for periodontal disease is scaling and root planning with the aim of reducing pathogenic bacteria. However, periodontal pathogens can rapidly recolonize treated areas. Probiotics have been proposed as novel tools for managing oral health by suppressing pathogenic bacteria through their anti-inflammatory effect, but the available data are controversial. Aim: Therefore, we performed a meta-analysis to study the effect of probiotics on periodontal pathogenic bacteria. Methods: The study was registered in PROSPERO under registration number CRD42018094903. A comprehensive literature search from four electronic databases (PubMed, Cochrane CENTRAL, Embase, and Web of Science) yielded nine eligible records for statistical analysis. Studies measuring bacterial counts in saliva and supra- and subgingival plaque were included. Bacterial counts were analyzed using standard mean difference (SMD) and by a random effects model with the DerSimonian-Laird estimation. Results: The results showed a significant decrease in the overall count of Aggregatibacter actinomycetemcomitans in the probiotic-treated group compared to the control at 4 weeks (SMD: -0.28; 95% CI: -0.56--0.01; p = 0.045) but not later. Analyzing the bacterial counts in subgroups, namely, in saliva and supra- and subgingival plaque, separately, yielded no significant difference. Probiotics had no significant effect on the overall count of Porphyromonas gingivalis at 4 weeks (SMD: -0.02; 95% CI: -0.35-0.31; p = 0.914) or later. Subgroup analysis also revealed no significant difference between treatment and control groups nor did probiotics significantly decrease the overall and subgroup bacterial counts of Prevotella intermedia, Tannerella forsythia, and Fusobacterium nucleatum. Conclusion: Our data support the beneficial effect of probiotics in reducing A. actinomycetemcomitans counts, but not of other key periodontal pathogenic bacteria in periodontal disease patients. However, due to the complex mechanism associated with periodontal disease and the limitations of the available studies, there is a further need for well-designed randomized clinical trials to assess the efficacy of probiotics.

Heterogeneity of human serum antibody responses to P. gingivalis in periodontitis: Effects of age, race/ethnicity, and sex

Aging humans display an increased prevalence and severity of periodontitis, although the mechanisms underlying these findings remain poorly understood. This report examined antigenic diversity of P. gingivalis related to disease presence and patient demographics. Serum IgG antibody to P. gingivalis strains ATCC33277, FDC381, W50 (ATCC53978), W83, A7A1-28 (ATCC53977) and A7436 was measured in 426 participants [periodontally healthy (n = 61), gingivitis (N = 66) or various levels of periodontitis (N = 299)]. We hypothesized that antigenic diversity in P. gingivalis could contribute to a lack of "immunity" in the chronic infections of periodontal disease. Across the strains, the antibody levels in the oldest age group were lower than in the youngest groups, and severe periodontitis patients did not show higher antibody with aging. While 80 % of the periodontitis patients in any age group showed an elevated response to at least one of the P. gingivalis strains, the patterns of individual responses in the older group were also substantially different than the other age groups. Significantly greater numbers of older patients showed strain-specific antibody profiles to only 1 strain. The findings support that P. gingivalis may demonstrate antigenic diversity/drift within patients and could be one factor to help explain the inefficiency/ineffectiveness of the adaptive immune response in managing the infection.

Host-derived diagnostic markers related to soft tissue destruction and bone degradation in periodontitis

BACKGROUND

A major challenge in clinical periodontics is to find a reliable molecular marker of periodontal tissue destruction with high sensitivity, specificity and utility.

OBJECTIVES

The aim of this systematic review is to evaluate available literature on 'the utility of molecular markers of soft and hard periodontal tissue destruction'.

MATERIALS AND METHODS

Based on the focused question, 'What is the utility of molecular markers of soft and hard periodontal tissue destruction', an electronic and manual search was conducted for human studies presenting clinical data for the potential of molecular markers of tissue destruction in biofluids; gingival crevicular fluid (GCF), saliva, and serum.

RESULTS

Papers fulfilling the inclusion criteria were selected. All relevant data from the selected papers were extracted and recorded in separate tables for molecules in GCF, saliva, and serum.

CONCLUSION

Within the defined limits of the Problem/Population, Intervention, Comparison, Outcome, the present analysis reveals that (a) no single or combination of markers exists that can disclose periodontal tissue destruction adequately; (b) while the most fruitful source of biomarkers for periodontal destruction appears to be in molecules tightly related to bone and soft tissue destruction, this remains to be objectively demonstrated. Currently, clinical measurements are still the most reliable.

A targeted fimA DNA vaccine prevents alveolar bone loss in mice after intra-nasal administration

AIM

To construct a dendritic cell (DC)-targeted DNA vaccine against FimA of Porphyromonas gingivalis and evaluate the immunogenicity and protection in mice.

MATERIALS AND METHODS

A targeted DNA plasmid pCTLA4-FimA, which encodes the signal peptide and extracellular regions of mouse cytotoxic T lymphocyte-associated antigen 4 (CTLA4), the hinge and Fc regions of human Igγ1 and FimA of P. gingivalis, was constructed. Mice were immunized with pCTLA4-FimA, the non-targeted DNA plasmid pFimA, which contains only fimA gene, or pCI vector intra-nasally. Serum and saliva antibody responses were detected by enzyme-linked immunosorbent assay. The protection against P. gingivalis-induced periodontitis was evaluated by measuring alveolar bone loss in mice.

RESULTS

Mice immunized with pCTLA4-FimA showed elevated levels of specific serum IgG and salivary IgA antibody responses compared with mice immunized with pFimA (p<0.01). Both pFimA and pCTLA4-FimA immunized groups showed significantly lower alveolar bone loss, with the magnitude protection greater in the latter (p<0.01), compared with the pCI immunized group.

CONCLUSIONS

The DC-targeted DNA construct pCTLA4-FimA enhanced both systemic and mucosal immunity following intra-nasal immunization. A DNA-based immunization strategy may be an effective way to attenuate periodontitis induced by P. gingivalis.

Salivary and plasma levels of Toll-like receptor 2 and Toll-like receptor 4 in chronic periodontitis

BACKGROUND

This cross-sectional study was planned to investigate whether patients with chronic periodontitis exhibit different salivary or plasma concentrations of Toll-like receptor (TLR) 2 and TLR4 compared to subjects who are clinically healthy.

METHODS

Whole saliva and plasma samples were obtained and full-mouth clinical periodontal measurements were recorded from 22 otherwise healthy patients with chronic periodontitis and 21 systemically and periodontally healthy control subjects. Salivary and plasma TLR2 and TLR4 levels were determined by enzyme-linked immunoassays. Data were tested statistically using Mann-Whitney U test.

RESULTS

The healthy group exhibited significantly lower values in all clinical measurements (P <0.001). The salivary TLR2 levels were similar in the two study groups (P >0.05). The patients with chronic periodontitis exhibited significantly higher salivary TLR4 (P <0.01) and plasma TLR2 and TLR4 levels (P <0.05).

CONCLUSION

The present findings support a hypothesis that inflammation increases expression of TLRs which leads to an increased detection of TLRs in saliva and plasma, which could be useful as a diagnostic test for periodontal diseases.

Humoral immune response to antigens of Porphyromonas gingivalis ATCC 33277 in chronic periodontitis

Introduction:

Periodontitis is a chronic disease that results from an interaction of a mixed bacterial challenge and the host response.

Objective:

The purposes of this study were to evaluate the IgG serum levels to Porphyromonas gingivalis antigens by ELISA in individuals with different periodontal conditions correlated with clinical parameters, and to analyze the immunoreactivity profiles by Western blotting.

Methods:

Serum IgG levels against the cell sonicate antigen from P. gingivalis ATCC 33277 of 28 patients with chronic periodontitis (CP), 10 patients with gingivitis (G) and 21 periodontally healthy individuals (H) were measured by ELISA and Western immunoblotting.

Results:

In the CP group, sera reactivity by ELISA was significantly higher than in the G and H groups (Kruskal-Wallis p<0.001; Dunnet t3 p= 0.001 and Dunnet t3 p= 0.0001). There was no statistically significant difference between G and HP reactivity (Dunnett t3 p=0.617). Among individuals with chronic periodontitis, the IgG-anti-P. gingivalis serum levels were positively correlated with percentage of clinical attachment level =5mm (r_s = + 0.375, p<0.05) and a negative correlation was found between IgG-anti-P. gingivalis levels and percentage of probing pocket depth 0-3mm (r_s = - 0. 411, p< 0.05). The analysis of sera immunoreactivity profiles to sonicate antigen by Western blotting showed differences between the sera of CP, G and H group individuals. The serum from CP frequently reacted with high molecular weight (103 kDa, 86 kDa, 72 kDa, 60 kDa, 58 kDa, 52 kDa) protein fractions.

Conclusions:

Serum levels of IgG anti-P. gingivalis distinguished individuals with chronic periodontitis, gingivitis and healthy periodontium. There was a correlation between clinical parameters and serum IgG levels against P. gingivalis. There was a difference in the recognition profile of protein fractions among the studied groups and some bands were more specific

Destructive periodontitis lesions are determined by the nature of the lymphocytic response

It is now 35 years since Brandtzaeg and Kraus (1965) published their seminal work entitled "Autoimmunity and periodontal disease". Initially, this work led to the concept that destructive periodontitis was a localized hypersensitivity reaction involving immune complex formation within the tissues. In 1970, Ivanyi and Lehner highlighted a possible role for cell-mediated immunity, which stimulated a flurry of activity centered on the role of lymphokines such as osteoclast-activating factor (OAF), macrophage-activating factor (MAF), macrophage migration inhibition factor (MIF), and myriad others. In the late 1970s and early 1980s, attention focused on the role of polymorphonuclear neutrophils, and it was thought that periodontal destruction occurred as a series of acute exacerbations. As well, at this stage doubt was being cast on the concept that there was a neutrophil chemotactic defect in periodontitis patients. Once it was realized that neutrophils were primarily protective and that severe periodontal destruction occurred in the absence of these cells, attention swung back to the role of lymphocytes and in particular the regulatory role of T-cells. By this time in the early 1990s, while the roles of interleukin (IL)-1, prostaglandin (PG) E(2), and metalloproteinases as the destructive mediators in periodontal disease were largely understood, the control and regulation of these cytokines remained controversial. With the widespread acceptance of the Th1/Th2 paradigm, the regulatory role of T-cells became the main focus of attention. Two apparently conflicting theories have emerged. One is based on direct observations of human lesions, while the other is based on animal model experiments and the inability to demonstrate IL-4 mRNA in gingival extracts. As part of the "Controversy" series, this review is intended to stimulate debate and hence may appear in some places provocative. In this context, this review will present the case that destructive periodontitis is due to the nature of the lymphocytic infiltrate and is not due to periodic acute exacerbations, nor is it due to the so-called virulence factors of putative periodontal pathogens.

Immunoglobulin G subclass antibody profiles in Porphyromonas gingivalis-associated aggressive and chronic periodontitis patients

BACKGROUND/AIMS

The immunoglobulin G (IgG) antibody response is considered to be protective and beneficial for the control of periodontal lesions. This study analysed IgG subclass antibody levels of Porphyromonas gingivalis in patients with both aggressive periodontitis (AgP) and chronic periodontitis (CP).

METHODS

Subgingival plaque and peripheral blood samples were collected from patients with localized AgP (n = 13), generalized AgP (n = 28) and generalized CP (n = 27) and from 14 periodontally healthy controls. P. gingivalis was identified in subgingival pockets using a polymerase chain reaction. Simultaneously, serum IgG subclass antibody against P. gingivalis whole cells/P. gingivalis fimbriae were measured using enzyme-linked immunosorbent assay.

RESULTS

P. gingivalis was frequently detected in periodontitis patients. Anti-P. gingivalis whole cell IgG1 was elevated in all P. gingivalis-positive patients in the three periodontitis groups. Although increased anti-P. gingivalis IgG1 was also observed in the bacterium-positive healthy controls, the level was lower than that found in the three periodontitis groups. Levels of IgG1, IgG2, IgG3 and IgG4 to P. gingivalis did not differ among bacterium-positive patients in the three periodontitis groups; a significant increase of IgG2 level was not observed in localized AgP. Anti-fimbriae IgG subclass levels of IgG1, IgG2 and IgG4 did not differ among bacterium-positive subjects in all groups, while the anti-fimbriae IgG3 level in generalized CP was significantly higher than that in localized and generalized AgP.

CONCLUSIONS

P. gingivalis infection elicited an IgG subclass antibody response in both periodontitis patients and healthy subjects, while higher anti-P. gingivalis IgG1 levels were found in the three periodontitis groups compared with the healthy control group.

Antibody response after single-visit full-mouth ultrasonic debridementversusquadrant-wise therapy

INTRODUCTION

The aim of this study was to compare serum antibody responses to periodontal pathogens after single-visit full-mouth ultrasonic debridement and quadrant-wise therapy.

MATERIAL AND METHODS

Thirty-six subjects with chronic periodontitis were randomized into three groups: quadrant-wise debridement in four visits, one-visit full-mouth debridement with water and with povidone iodine. Blood samples were collected before and immediately after treatment and 1, 3 and 6 months post-therapy. Serum antibody titres and avidity to Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Prevotella intermedia and Treponema denticola were determined by enzyme-linked immunosorbent assay (ELISA) and thiocyanate ELISA, respectively.

RESULTS

IgG titres to P. gingivalis significantly decreased at 1, 3 and 6 months in full-mouth debridement with water group, while significant reductions were seen only at 3 and 6 months after quadrant-wise debridement. Both full-mouth groups showed significant reduction in IgG titres to A. actinomycetemcomitans at 3 and 6 months. Significant increases in antibody avidity to P. gingivalis and A. actinomycetemcomitans were noted 3 months following full-mouth debridement with povidone.

CONCLUSION

Both full-mouth and quadrant treatments generally resulted in a decrease in antibody titres and increase in antibody avidity. Full-mouth debridement induced an earlier reduction of IgG titre to P. gingivalis and A. actinomycetemcomitans, than quadrant-wise therapy.

Gingipain-Specific IgG in the Sera of Patients With Periodontal Disease Is Necessary for Opsonophagocytosis ofPorphyromonas gingivalis

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.

Elevated serum IgG titer and avidity to Actinobacillus actinomycetemcomitans serotype c in Japanese periodontitis patients

AIM

The purpose of this study was to characterize serum antibody responses to different serotypes of Actinobacillus actinomycetemcomitans strains in various forms of periodontitis and to determine whether any specific type of A. actinomycetemcomitans was associated with any specific form of periodontitis in a Japanese population.

METHODS

Sonicated whole cell and autoclaved serotype antigens of A. actinomycetemcomitans were used. Serum IgG titer and avidity to A. actinomycetemcomitans were measured by enzyme-linked immunoabsorbant assay (ELISA) and ammonium thiocyanate-dissociation ELISA, respectively, in 46 aggressive periodontitis patients (8 localized, 38 generalized), 28 chronic periodontitis patients, and 18 periodontally healthy subjects. The presence of A. actinomycetemcomitans in plaque and saliva samples was determined using polymerase chain reaction.

RESULTS

Generalized aggressive and chronic periodontitis patients exhibited significantly higher IgG titers than healthy subjects to both sonicated and autoclaved antigens of serotype c strains, while IgG titer to serotype b (Y4) was significantly higher in localized aggressive periodontitis patients compared to healthy subjects. No A. actinomycetemcomitans was detected in localized aggressive periodontitis patients. A. actinomycetemcomitans-positive patients exhibited significantly higher IgG titer and avidity to serotype c than A. actinomycetemcomitans-negative patients. In A. actinomycetemcomitans-positive patients, a significantly positive correlation was observed between antibody titer and avidity to serotype c. A. actinomycetemcomitans-positive patients with generalized aggressive periodontitis showed lower IgG avidities to serotype c than those with chronic periodontitis, though no statistically significant difference was found.

CONCLUSION

A. actinomycetemcomitans serotype c may play a significant role in chronic and generalized aggressive periodontitis, while A. actinomycetemcomitans serotype b may be associated with localized aggressive periodontitis in a Japanese population.

Plasma antibody levels in periodontitis patients and controls

BACKGROUND

A major aspect of the adaptive host response in periodontitis is the production of antibodies. Several risk and susceptibility factors for periodontitis, including smoking, age and composition of the subgingival microflora, have also been suggested to influence antibody production.

AIM

The present study was conducted to investigate plasma levels of immunoglobulin (Ig) G, A and M antibodies in periodontitis patients of Caucasian European heritage in relation to disease severity, smoking, diagnosis and prevalence of periodontopathogens.

METHODS

In this study, 29 patients with severe periodontitis, 51 with moderate periodontitis and 55 controls without periodontal destruction were enrolled. From the total of 80 patients, 18 were diagnosed with aggressive periodontitis and 62 with chronic periodontitis. Total IgG, IgA and IgM as well as IgG isotypes were analyzed in plasma samples.

RESULTS

Levels of total IgG, IgA and IgM were not different between patients and controls; however, in periodontitis, higher levels of IgG1 and IgG2 were observed. Smoking appeared to be significantly and inversely related to antibody levels in periodontitis, in particular for total IgG and IgG2. The absence of an elevated total IgG and IgG2 in smoking patients was irrespective of severity, prevalence of periodontal pathogens and diagnosis. The elevation of total IgG and IgG1 and IgG2 in non-smoker periodontitis patients was observed in patients with moderate periodontitis and even greater in patients with severe periodontitis, but was independent whether patients were infected with Actinobacillus actinomycetemcomitans or Porphyromonas gingivalis and independent of diagnosis. Clinically, it was observed that patients who smoked had more periodontal bone loss; the current findings on antibody levels may be one of several mechanisms related to more extensive periodontal breakdown in smoker patients.

CONCLUSION

The current study shows that non-smoker periodontitis patients have higher levels of total IgG and IgG2 than smoker periodontitis patients.

Porphyromonas gingivalis-specific immunoglobulin G prevents P. gingivalis-elicited oral bone loss in a murine model

Active immunization with Porphyromonas gingivalis whole-cell preparations has been shown to prevent P. gingivalis infection and oral bone loss. Employing passive antibody transfer and opsonization, we demonstrate with this study that immunization-elicited P. gingivalis-specific immunoglobulin G facilitates clearance of P. gingivalis in a subcutaneous chamber model and prevents P. gingivalis-elicited oral bone loss.

Quadrant root planing versus same-day full-mouth root planing. III. Dynamics of the immune response

OBJECTIVES

The aim of this study was to determine whether same-day full-mouth scaling and root planing (FM-SRP) and quadrant scaling and root planing (Q-SRP) resulted in variations in the systemic humoral immune response dynamics (antibody titres and avidity) during active treatment and 3 and 6 months post-therapy.

MATERIALS AND METHODS

Forty patients with chronic periodontitis were recruited into this study. Subjects were randomised into two groups and received either scaling and root planing quadrant by quadrant at 2-weekly intervals (Q-SRP group) or same-day full-mouth scaling and root planing (FM-SRP group). Clinical measurements and serum samples were obtained at baseline and approximately 6 weeks after the last clinical intervention (R1) and 6 months after the initiation of therapy (R2). Furthermore, serum samples were obtained from each patient undergoing therapy (Q-SRP and FM-SRP) at 3 bi-weekly instances so as to determine the short-term effects of each session of scaling and root planing on the dynamics of the humoral immune response. Serum antibody titre was assayed by enzyme-linked immunosorbent assay (ELISA) and antibody avidity was measured by thiocyanate dissociation against five putative periodontal pathogens: Porphyromonas gingivalis; Actinobacillus actinomycetemcomitans; Prevotella intermedia; Treponema denticola and Bacteroides forsythus.

RESULTS

Both therapies resulted in similar antibody titre reductions against the majority of the organisms tested and although there was a distinct trend for antibody avidity to increase following therapy, this was not found to be statistically significant, reflecting marked inter-individual variation. In addition, no evidence emerged from this study to support increased antibody titres following the active phases of both treatment approaches due to an inoculation effect. Nevertheless, significant short-term increases in antibody avidity to most test bacteria were noted for both treatment strategies.

CONCLUSION

Both therapies were associated with a reduction in antibody titres and an increase in the binding ability or avidity of antibodies, but there was a marked inter-subject variability and statistical significance was reached for only some of the test bacteria. No significant differences in the humoral antibody dynamics were found between the two treatment approaches.

Salivary IgA in response to periodontal treatment

There is evidence that the quantity of antigen load is crucial for the activation of IgA immune responses. In order to investigate the relevance of these findings in aggressive periodontitis, salivary antibody responses were measured during non-surgical and antibiotic treatment. Twenty-one patients with generalized aggressive periodontitis were monitored for total salivary IgA and IgA reactive to Porphyromonas gingivalis in resting and stimulated whole saliva. Non-surgical treatment included full-mouth professional tooth cleaning and subgingival scaling and root planing (SRP) under local anesthesia. Patients were recalled at 3 months and 6 months following systemic antibiotic treatment. Non-parametric statistics showed significant improvements in the clinical parameters in all patients. Between baseline and 4 wk following SRP, median concentrations of total IgA decreased both in resting (-46%) and in stimulated (-33%) saliva. The P. gingivalis-specific IgA activity showed a twofold increase at 4 wk after SRP. In addition to these changes, periodontal treatment of aggressive periodontitis did not appear to affect salivary IgA, and there were no significant correlations of IgA to the clinical parameters. In conclusion, salivary IgA responses during periodontal treatment were not found to have a diagnostic or prognostic significance.

Protective humoral immunity induced by surface-associated material from Actinobacillus actinomycetemcomitans in mice

The aim of the present study was to determine the role of antibodies specific to anti-surface-associated material from Actinobacillus actinomycetemcomitans (anti-SAM-Aa) in an infection induced by this periodontopathogen in mice. When SAM-Aa obtained by saline extraction of A. actinomycetemcomitans Y4 was separated on one-dimensional gel electrophoresis, this constituent contained antigen fragments with molecular weights ranging from 14000 to 79000. Immunoblot analysis revealed that increased antigen dose/immunization resulted in increased numbers of antigen epitopes recognized by serum antibodies of the immunized mice. Rapid healing of the primary lesions and high levels of specific IgG antibodies after challenge with live A. actinomycetemcomitans were seen in the immunized mice, especially at the highest-dose level of 100 microg/immunization. Transfer of SAM-Aa-immunized, but not the SAM-Aa-immunized and adsorbed, serum prior to challenge with live bacteria led to rapid healing of the lesions in the recipient mice. Increased phagocytosis of A. actinomycetemcomitans by murine macrophages (RAW264.7 cells) was observed when this periodontopathogen was opsonized by the SAM-Aa-immunized, but not SAM-Aa-immunized and adsorbed, serum. These results suggest that in mice, SAM-Aa antigens may induce protective antibodies by acting, at least, as an opsonin against challenge with live A. actinomycetemcomitans.

Changes in subgingival microflora and humoral immune response following periodontal therapy

OBJECTIVES

To investigate the effect of scaling and root planing (SRP) on the microflora and humoral immune response in adult periodontitis.

MATERIALS & METHODS

Clinical measurements, subgingival plaque samples, gingival crevicular fluid and sera were taken from 4 sites in 28 adult periodontitis patients before and after SRP. Polymerase chain reaction was used to determine the presence of A. actinomycetemcomitans, P. gingivalis, B. forsythus, P. intermedia, and T. denticola. ELISA was used to investigate the systemic and local antibody titres to these organisms, and thiocyanate dissociation for the determination of serum antibody avidity.

RESULTS

SRP produced a good clinical improvement. On a subject basis there was little significant change in the microflora. However, on a site basis, there were significant reductions in P. intermedia, B. forsythus and T. denticola. There was little change in systemic and local antibody titres following SRP, although there was a significant reduction in antibody avidity to P. gingivalis and P. intermedia

CONCLUSION

Post-therapy clinical improvement was associated with a reduction in bacterial prevalence, but statistical significance was only reached at a site level and this microbial reduction was not significant for all organisms. No significant post-therapy effects on the humoral immune response were noted other than a reduced antibody avidity to P. gingivalis and P. intermedia. The lack of a clear pattern in the humoral immune response may reflect a failure of the host response to produce adequate levels of biologically functional antibodies, and complex interactions between the subgingival flora and the host response.

"Checkerboard" assessments of periodontal microbiota and serum antibody responses: a case-control study

BACKGROUND

We explored the association between subgingival microbial profiles and serum IgG responses to periodontal microbiota in relation to clinical periodontal status.

METHODS

One hundred thirty-one (131) periodontitis patients aged 29 to 74 years (mean 51.8) were age- and gender-matched with 74 periodontally intact controls (range 26 to 77, mean 49.3). Smoking habits and health history were recorded and assessments of plaque, bleeding on probing, probing depth, and attachment level were performed at 6 sites per tooth on all present teeth, excluding third molars. Subgingival plaque samples were obtained from each tooth in one upper and one lower quadrant (maximum 14 samples/subject; 2,440 samples total) and analyzed with respect to 19 species by means of whole genomic DNA probes. Serum IgG antibodies against the same 19 species were assessed by an immunoassay.

RESULTS

Cases displayed an average of 22.7 teeth, 20.3 sites with probing depth > or =6 mm, and 18.9 sites with attachment loss > or =6 mm. Corresponding figures for controls were 27.1, 0.1, and 1.0, respectively. Heavy smoking was 3 times more frequent among cases than controls (32.1% versus 9.6%). Higher levels of Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella intermedia, Prevotella nigrescens, Prevotella melaninogenica, Bacteroides forsythus, Fusobacterium nucleatum, Treponema denticola, Eubacterium nodatum, Peptostreptococcus micros, and Campylobacter rectus were found in cases and higher levels of Eikenella corrodens, Veillonella parvula, and Actinomyces naeslundii in controls. Cases displayed higher IgG levels against P. gingivalis and Actinobacillus actinomycetemcomitans, while controls displayed higher levels against F. nucleatum, T. denticola, E. nodatum, and Capnocytophaga ochracea. Positive correlations between bacterial colonization and antibody responses were identified for 9 species in controls. In cases, however, statistically significant correlations were observed for only 3 species out of which only one was positive (V. parvula). Both bacterial levels and antibody responses declined in ages over 55 years. A logistic regression employing selected elements of bacterial colonization and antibody responses as independent variables resulted in 81.1% correct diagnosis, with sensitivity of 83.1%, specificity of 77.8%, positive predictability of 86%, and negative predictability of 73.7%. Smoking did not reach statistical significance in this model.

CONCLUSION

A combined microbial colonization/antibody response profile can effectively discriminate between periodontitis patients and periodontally intact controls.

Oral ecology and person-to-person transmission of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis

The ecological characteristics of the oral cavity are dissimilar for A. actinomycetemcomitans and for P. gingivalis, as judged by differences in their colonization preferences and patterns, associations with periodontal disease parameters, relationships with the subgingival microbiota and the type of periodontitis and their clonal persistence in the oral cavity. These features also suggest that as a periodontal pathogen, A. actinomycetemcomitans is different from P. gingivalis. Probably in most infected individuals, low levels of A. actinomycetemcomitans can persist for years in equilibrium with the host and the resident oral microbiota. However, it is well established that A. actinomycetemcomitans can cause disease in some individuals or in some circumstances when the regulatory mechanisms are unable to maintain homeostasis in the ecosystem. Elevated A. actinomycetemcomitans proportions of the biota can be regarded as a sign of ecological imbalance, leading to increased risk of periodontal destruction. There is also evidence showing elevated pathogenic potential of certain A. actinomycetemcomitans clones. Although A. actinomycetemcomitans seems to be relatively rarely transmitted between cohabiting adults, transmission can occur to periodontally healthy children of A. actinomycetemcomitans-positive parents. Parents and children may share factors that promote successful oral colonization of A. actinomycetemcomitans, or the window of opportunity is in childhood. Therefore, to prevent parent-child transmission of A. actinomycetemcomitans, bacterium-positive parents of young children are optimal targets for enhanced information and treatment. In selected populations, screening for specific clones of A. actinomycetemcomitans has been employed in prevention of peridontitis. Future research aiming at finding the reasons which cause the changes in the oral homeostasis to allow the growth of A. actinomycetemcomitans may give insight into novel prevention strategies for A. actinomycetemcomitans-associated periodontitis. Compared with A. actinomycetemcomitans, P. gingivalis shows a different pattern of coexistence with the host. In periodontal health or in children, P. gingivalis is absent or only rarely detected. When present, P. gingivalis is commonly recovered in high numbers from dentitions exhibiting inflamed periodontitis and poor oral hygiene. Contrary to A. actinomycetemcomitans, the data on the vertical transmission of P. gingivalis are limited. The major infection route of P. gingivalis seems to be between adults, indicating that P. gingivalis commonly colonizes in an established oral microbiota. These characteristics suggest that the degree of tolerance between P. gingivalis and the host is inferior to that between A. actinomycetemcomitans and the host. It appears that the association of P. gingivalis with disease is a rule rather than an accidental incident. On these grounds, it seems that the host-P. gingivalis relationship approaches antibiosis. Since P. gingivalis infection is related to a typical periodontal eco-pathology, the susceptibility to person-to-person transmission of this pathogen may be controlled by periodontal treatment and emphasizing the significance of high standard oral hygiene.

Doença periodontal: estudo da resposta imune humoral

Foram comparados os níveis de IgG e IgA séricas e de IgG e IgA secretora (IgA-S) salivares reativas com Actinobacillus actinomycetemcomitans (Aa) e dosadas IgM, IgG e IgA séricas totais em pacientes com Periodontite de Incidência Precoce (PIP), Periodontite de Adulto (PA) e controles saudáveis (sem doença periodontal). Os níveis de anticorpos para Aa foram determinados por ELISA, e a dosagem de Igs séricas totais foi realizada por imunodifusão radial simples, utilizando-se como antígenos extrato sonicado de uma mistura de cinco isolados de Aa provenientes de pacientes com PIP e extrato sonicado de Aa de referência FDC Y4. Não foi observada diferença significativa entre os níveis séricos de anticorpos IgG e IgA e os níveis salivares de anticorpos IgG e IgA-S para Aa nos grupos PIP (n = 9), PA (n = 20) e indivíduos sadios (n = 20). Esses resultados sugerem a inexistência de alterações significativas na resposta imune humoral anti-Aa em pacientes com periodontite. A dosagem de Igs séricas totais também não revelou diferença estatisticamente significante entre pacientes com PIP (n = 9), PA (n = 9) ou controles saudáveis (n = 9).

Serum IgG antibody response to Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis: implications for periodontal diagnosis

The relationship of the serum antibody titer and avidity to the putative periodontal pathogens Actinobacillus actinomycetemcomitans (Aa) strains Y4 and 29523 and Porphyromonas gingivalis (Pg) strain 381 were examined in relation to clinical parameters in 26 gingivitis and 28 periodontitis patients. The relationship of antibody titer and avidity to infection with the homologous organism was also examined in a subset of 30 patients. Antibody titer was determined by an enzyme-linked immunosorbent assay, and antibody avidity was assessed using a dissociation assay. Considering all patients, there was a significant negative correlation between mean probing depth and antibody titer (r=-0.28) and avidity (r=-0.28) to Aa Y4. There was a significant positive correlation of probing depth and antibody titer (r=0.46) and avidity (r=0.46) to Pg. The correlation of antibody titer and avidity to Aa and infection with Aa Y4 (r=-0.32, r=-0.21) and Aa 29523 (r=-0.35, r=-0.39) was negative, while the correlations of titer and avidity to Pg and presence of the organisms was strongly positive (r=0.40, r=0.35). These data indicate that the relationship of serum antibody titer and avidity to clinical parameters of periodontal disease severity and the level of infection with the homologous organism appears to be different for Aa and Pg. The development of an antibody response to Aa appears to protect the individual from infection with the organism. In contrast, the development of an antibody response to Pg was not able to eliminate the infection. These results should be considered when developing a diagnostic strategy for periodontal disease utilizing the humoral immune response.

Dynamics of serum immunoglobulin G avidity for Porphyromonas gingivalis in adult periodontitis

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.

Relationship between serum antibody levels and subgingival colonization of Porphyromonas gingivalis in patients with various types of periodontitis

Porphyromonas gingivalis is considered to be an important pathogen in periodontitis. The present study investigates the relationship between serum anti-P. gingivalis IgG antibody levels and the subgingival distribution of P. gingivalis in patients with periodontitis. We examined subgingival plaque samples from 15 patients with adult periodontitis (AP), 8 patients with early-onset periodontitis (EOP), and 6 clinically healthy individuals. The samples were collected from periodontal pockets or gingival crevices of all remaining teeth in each subject. The total number of samples was 3,024, ranging from 76 to 120 per subject. Probing depth and bleeding at each sample site were recorded. P. gingivalis was detected using a non-radioactive whole genomic DNA probe. Serum samples were taken from the subjects, and the serum anti-P. gingivalis IgG antibody titer was determined by enzyme-linked immunosorbent assay (ELISA). P. gingivalis was recovered from all AP and EOP patients, and from 3 of the 6 healthy subjects. Two significant positive correlations were observed among the subjects. The serum anti-P. gingivalis IgG antibody titer correlated with detection frequency of P. gingivalis, and the antibody titer correlated with the amount of P. gingivalis detected. Higher levels of P. gingivalis were detected in the EOP group than in the AP group. However, no significant difference was found in the serum IgG titer levels between EOP and AP patients. These findings suggest a direct relationship between the serum anti-P. gingivalis IgG levels and subgingival P. gingivalis colonization; however, the functional capabilities of IgG antibodies may vary among the various types of periodontitis patients.

Putative periodontal pathogens, antibody titres and avidities to them in a longitudinal study of patients with resistant periodontitis

OBJECTIVE

To study changes in antibody titres and antibody avidities to putative periodontal pathogens in patients with resistant periodontitis and to compare these findings with the result of culture of these pathogens.

SUBJECTS AND METHODS

Patients meeting strict clinical criteria in whom periodontal therapy had failed to prevent disease progression were studied microbiologically and immunologically over a 75-week period. Particular reference was made to the isolation of Actinobacillus actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) together with changes in antibody titres and avidities to these organisms between baseline examination and week 75.

RESULTS

Pg was eliminated following antibiotic treatment but metronidazole and amoxycillin therapy failed to remove Aa in all cases. Antibody avidities to these pathogens were higher in patients than in matched controls but no change in avidity was noted during the course of treatment. Most antibody titres were not significantly higher in patients than in controls.

CONCLUSIONS

Continued disease progression characterised these patients who, nevertheless, mounted an immune response to the periodontal pathogens but this appeared to be inadequate to stop the disease.