Serum IgA and IgG antibodies to Treponema vincentii and Treponema denticola in adult periodontitis, juvenile periodontitis and periodontally healthy subjects

PerioVax3, a key antigenic determinant with immunoprotective potential against periodontal pathogen

Treponema (T.) denticola is one of the key etiological agents in the development of periodontitis. The major outer sheath protein (Msp) of T. denticola has been shown to mediate pathogenesis and to facilitate adhesion of T. denticola to mucosal surfaces. This study aimed to find short polypeptides in the amino acid sequence of Msp which may be immunogenic and might elicit protective antisera against T. denticola. The complete msp sequence was divided into six fragments and the corresponding genes were cloned and expressed. Antisera against the polypeptides were raised in rabbits and fragment 3 (F3), hereinafter called PerioVax3 was the most potent fragment of the Msp in terms of yielding high titer antiserum. An adhesion assay was done to examine the inhibitory effects of antisera on the attachment of T. denticola to human gingival fibroblasts (HGFs) and human fibronectin. Antiserum against PerioVax3 significantly inhibited attachment of T. denticola to the substratum. Also, antiserum against PerioVax3 inhibited detachment of HGFs upon T. denticola exposure. To begin examining the clinical relevance of this work, blood samples from 12 sever periodontitis patients were collected and the sera were used in western blotting against the recombinant polypeptides. Periodontitis patient antisera exclusively detected PerioVax3 in western blotting. The data suggest that PerioVax3 carries epitopes that may trigger humoral immunity against T. denticola, which may protect against its adhesion functions. The complexity of periodontitis suggests that PerioVax3 may be considered for testing as a component of an experimental multivalent periodontal vaccine in further preclinical and clinical studies.

Antimicrobial susceptibility profiles of oral Treponema species

Treponemes occur in the microflora of the dental plaque. Certain Treponema species that are frequently isolated from chronic periodontitis lesions are involved in its initiation and progression. In addition to mechanical instrumentation, antimicrobial agents are used as an adjunctive treatment modality for periodontitis. Despite its importance for successful antimicrobial treatment, information about susceptibility is limited for Treponema species. The aim of this study was to assess the susceptibility of Treponema denticola strains, Treponema socranskii, and Treponema vincentii to eleven antimicrobial agents. The minimum inhibitory and minimum bactericidal concentrations of these antimicrobial agents revealed strain-specific variation. Doxycycline, minocycline, azithromycin, and erythromycin were effective against all Treponema species tested in this study, whereas fluoroquinolones only exhibited an equivalent effectiveness on T. socranskii. The susceptibility of one T. denticola strain, T. socranskii, and T. vincentii to kanamycin was influenced by prior exposure to aerobic conditions. The susceptibility to quinolone drugs varied among strains of T. denticola, although they share an amino acid sequence identity of greater than 99% for DNA gyrase (type II topoisomerase) subunit A. In addition, an ATP-binding cassette (ABC) transporter inhibitor assay for T. denticola indicated that the transport of quinolone drugs is partially related to this transporter, although there may be parallel transport mechanisms. Our results provide important insights into antimicrobial agent-Treponema dynamics and establish a basis for developing an appropriate adjunctive therapy for periodontal disease.

Microbiologic and immunologic characteristics of periodontal disease in Hispanic americans with type 2 diabetes

BACKGROUND

The microbiology of periodontitis in type 1 diabetes has been reported, but less is known about type 2 diabetes. Moreover, these data have not linked microbial colonization, host response, and clinical presentation in type 1 or type 2 diabetes. The objectives of this study were to relate periodontal status, periodontal microorganisms, and host-response characteristics in Hispanic Americans with type 2 diabetes.

METHODS

Plaque and serum samples were obtained from 63 Hispanic American subjects with and without type 2 diabetes. The microbiology of subgingival plaque samples was evaluated using DNA checkerboard hybridization, and serum antibody to a battery of oral microorganisms was determined using an enzyme-linked immunosorbent assay.

RESULTS

In general, similar pathogens were present in periodontitis sites from subjects with and without type 2 diabetes, although the periodontitis sites in diabetes showed a higher frequency of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), and Campylobacter spp. Serum antibody to Campylobacter rectus was elevated in type 2 diabetes, whereas antibody to P. gingivalis and C. rectus were elevated in subjects with periodontitis, irrespective of diabetes status. Stratification of the population based upon antibody to P. gingivalis or C. rectus suggested a linkage between elevated antibody to P. gingivalis, increased frequency of diabetes, and significantly worse periodontitis.

CONCLUSION

The increased severity of periodontal disease with type 2 diabetes may reflect an alteration of the pathogenic potential of periodontal bacteria and/or a modification of the characteristics of the host's inflammatory response that may contribute to a breakdown in the homeostasis of the periodontium.

Serum antibody levels in smoker and non-smoker saudi subjects with chronic periodontitis

BACKGROUND

Cigarette smoking is a significant risk factor for the initiation and progression of periodontal disease. Studies have shown altered serum and gingival crevicular fluid inflammatory cytokine profiles, immune cell function, and altered proteolytic regulation in smokers. The observations are not consistent, and to date, there is no clear mechanism to explain how smoking may affect periodontal disease. Hence, the present study was undertaken to assess the alterations of serum immunoglobulin levels in smokers with periodontitis and its potential role as a risk indicator of the disease process.

METHODS

In this study, 30 patients who smoked and 30 patients who did not smoke with chronic periodontitis and 30 healthy subjects were enrolled. Serum immunoglobulin (Ig) G, IgA, and IgM levels were estimated with immunoturbidimetric assay. The IgG subclass (IgG1, IgG2, IgG3, and IgG4) levels were performed using single radial immunodiffusion assay.

RESULTS

Levels of serum IgG and IgA were significantly lower in smokers compared to non-smokers and healthy controls (P <0.001). Although IgM levels were low in smokers, it was not significant. Of the four subclasses of IgG studied, the IgG2 was found to be significantly lower among smokers with periodontitis.

CONCLUSIONS

Current observations indicate that cigarette smoking may be associated with the suppression of B-cell function and immunoglobulin production. The alteration of antibody levels further explains the potential mechanism by which smoking exacerbates periodontal disease. Further studies at the molecular level may highlight the specific mechanism by which tobacco can interact with cells of the immune system and its impact on periodontal disease process.

Association of Eubacterium nodatum and Treponema denticola with human periodontitis lesions

BACKGROUND

The purpose of the present investigation was to compare the levels, proportions and percentage of sites colonized by 40 bacterial species in subgingival plaque samples from periodontally healthy subjects and patients with chronic periodontitis to seek possible pathogens other than the consensus pathogens Porphyromonas gingivalis and Tannerella forsythia.

METHOD

Subgingival plaque samples were taken from the mesial aspect of each tooth in 635 subjects with chronic periodontitis and 189 periodontally healthy subjects. The samples were individually analyzed for their content of 40 bacterial species using checkerboard DNA-DNA hybridization (total samples = 21,832). Mean counts, % DNA probe counts and percentage of sites colonized at >10(5) were determined for each species in each subject and then averaged in each clinical group. Significance of difference between groups was determined using the Mann-Whitney test. Association between combinations of species and periodontal status was examined by stepwise logistic regression analysis. Analyses were repeated using a subset of subjects from both clinical groups who had proportions of P. gingivalis plus T. forsythia less than the median (4.42%) found in periodontally healthy subjects. All analyses were adjusted for multiple comparisons.

RESULTS

For the 824 subjects the consensus pathogens P. gingivalis and T. forsythia as well as Eubacterium nodatum and Treponema denticola had significantly higher mean counts, proportions and percentage of sites colonized in samples from subjects with periodontitis than from periodontally healthy subjects. There were significantly more Capnocytophaga gingivalis, Streptococcus gordonii and Veillonella parvula in periodontally healthy subjects. E. nodatum, T. denticola, Streptococcus oralis, Streptococcus intermedius, Fusobacterium nucleatum ssp. vincentii all had higher counts and proportions in diseased than healthy subjects who had low proportions of P. gingivalis and T. forsythia. Logistic regression analysis indicated that the same species groups were associated with disease status after adjusting for the proportions of the other species.

CONCLUSIONS

This investigation confirmed the strong association of P. gingivalis and T. forsythia with chronic periodontitis and emphasized a strong association of E. nodatum and T. denticola with periodontitis whether in the presence or absence of high levels of the consensus pathogens. Other species, including S. oralis, Eikenella corrodens, S. intermedius and F. nucleatum ssp. vincentii, were associated with disease when P. gingivalis and T. forsythia were present in low proportions.

Lack of humoral immune protection against Treponema denticola virulence in a murine model

This study investigated the characteristics of humoral immune responses to Treponema denticola following primary infection, reinfection, and active immunization, as well as immune protection in mice. Primary infection with T. denticola induced a significant (400-fold) serum immunoglobulin G (IgG) response compared to that in control uninfected mice. The IgG response to reinfection was 20, 000-fold higher than that for control mice and 10-fold higher than that for primary infection. Mice actively immunized with formalin-killed treponemes developed serum antibody levels seven- to eightfold greater than those in animals after primary infection. Nevertheless, mice with this acquired antibody following primary infection or active immunization demonstrated no significant alterations of lesion induction or decreased size of the abscesses following a challenge infection. Mice with primary infection developed increased levels of IgG3, IgG2b, and IgG2a antibodies, with IgG1 being lower than the other subclasses. Reinfected mice developed enhanced IgG2b, IgG2a, and IgG3 and less IgG1. In contrast, immunized mice developed higher IgG1 and lower IgG3 antibody responses to infection. These IgG subclass distributions indicate a stimulation of both Th1 and Th2 activities in development of the humoral immune response to infection and immunization. Our findings also demonstrated a broad antigen reactivity of the serum antibody, which was significantly increased with reinfection and active immunization. Furthermore, serum antibody was effective in vitro in immobilizing and clumping the bacteria but did not inhibit growth or passively prevent the treponemal infection. These observations suggest that humoral immune responses, as manifested by antibody levels, isotype, and antigenic specificity, were not capable of resolving a T. denticola infection.

Identification of a fliG homologue in Treponema denticola

Using a bacteriophage lambda library of Treponema denticola (Td) ATCC 35405 DNA, and, as a reagent, sera derived from individuals with advanced adult periodontal disease, a variety of recombinant clones producing antigens of this oral spirochete have been isolated. Nucleotide sequence analysis of a clone expressing three immunoreactive antigens has revealed the presence of an open reading frame highly homologous to the flagellar switch/motor protein, FliG, which is known to be essential for flagellar assembly and rotation, and chemotaxis in enteric bacteria. The deduced amino-acid sequence of the treponemal FliG protein had 73% similarity (55% identity) to the Bacillus subtilis FliG protein, and showed significant, but lesser homologies to Gram- FliG proteins. Sequence analysis of regions flanking fliG indicated that this gene is immediately preceded by a fliF homologue, further supporting that the cloned DNA encodes FliG of Td. The findings imply that although the signals for control of chemotaxis may be distinctly different in spirochetes, at least some of the molecules involved in torque generation, control of flagellar rotation and signal transduction are highly conserved with other bacteria. The stronger homology of the spirochete FliG with those of Gram+ bacteria is also consistent with recent analyses of other spirochetal genes.

Isolation and characterization of a 53 kDa major cell envelope protein antigen from Treponema denticola ATCC 35405

A major cell envelope protein was purified from the cell envelope fraction of Treponema denticola ATCC 35405 by ion exchange chromatography after extraction with Zwittergent 3-14. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed a relative molecular mass of 53 kDa for this protein with a pI of 6.3-6.8. Amino acid analysis revealed that this protein contained high proportions of hydrophobic amino acids (40.4%), and no cysteine could be detected. The N-terminus of the protein was blocked to Edman degradation. Rabbit antiserum raised against the purified 53 kDa protein reacted with the outer envelope of the T. denticola cell surface as confirmed by immunoelectron microscopy. This rabbit antiserum reacted with 4 of the 11 strains of treponemes tested in this study. Sera from 9 to 18 periodontitis patients reacted strongly with this 53 kDa cell envelope protein of T. denticola as determined by immunoblotting analysis.

Common and specific antigens of several treponemes detected by polyclonal antisera against major cellular proteins

Thirteen polypeptide antigens with molecular weights ranging from 34 kDa to 83 kDa were selected and their antigenic behaviors and distribution were examined in 12 strains of microorganisms including Treponema, Borrelia, Leptospira and Leptonema. Immunoblot analysis demonstrated that 45 kDa and 83 kDa polypeptides of Treponema socranskii subsp. buccale ATCC 35534, 53 kDa antigen of Treponema denticola ATCC 33520 and 44 kDa polypeptide of the strain G7201 were strain-specific. The 34, 62, 66 and 84 kDa polypeptide antigens were detected in all 8 treponemal strains examined. T. denticola ATCC 33520 and ATCC 35404 possessed 38 kDa, 48 kDa, 52 kDa and 72 kDa common polypeptide antigens. All 12 strains possessed the 84 kDa polypeptide antigen. Immunoelectron microscopy demonstrated that the 34 kDa and 38 kDa polypeptide antigens were located on the axial flagella and that other polypeptide antigens were located on the outer envelopes or wall-membrane complexes.

Spirochaetes in oral infections

Oral spirochaetes, which are small-, medium- or large-sized, include species of the genus Treponema, many of which have not yet been cultured. They are found in root canal infections, pericoronitis, gingivitis and periodontitis, constituting up to 10% of the flora in endodontic abscesses, 30% in acute necrotizing ulcerative gingivitis, and 56% in advanced marginal periodontitis. The strong proteolytic activity of these organisms probably make them causes of infection rather than consequences. Being able to penetrate tissue, they bring their enzymes, metabolic products, and endotoxins, in direct contact with target cells. This may perturb essential functions of host cells and immunoglobulins. Enzyme activities may also help fulfil the complex growth requirements of spirochaetes in vivo. Reaction between infected periodontal tissue and monoclonal antibodies to Treponema pallidum has suggested that uncharacterized pathogen-related oral spirochaetes have surface structures and functions analogue to this well recognized pathogen. This warrants a more intensified search for the role of spirochaetes in oral infections.

Characterization of the wheat germ agglutinin-binding property of Treponema denticola

Lectins were used to characterize glycoconjugates on the cell surface of Treponema denticola, a suspected periodontopathogen. Bacteria were first screened by light microscopy using fluorescein isothiocyanate-coupled lectins. Wheat germ agglutinin (WGA) showed a high reactivity to T. denticola. While the WGA-binding activity was accentuated following heating or detergent treatments of bacterial cells, the reaction was inhibited by incorporation of competing carbohydrates. Scanning and transmission electron microscope studies were conducted in order to characterize the distribution of the WGA-binding sites on the cell surface of T. denticola. Data from these studies confirmed that heat treatment increases the percentage of labeled profiles and suggest that the WGA-binding sites are concentrated on specific regions on the spirochete surface. Initial biochemical analysis indicated that the high reactivity to WGA resides in a peptidoglycan fraction.

Antigenic behaviors of two axial flagellar proteins detected in Treponema denticola

Two polypeptide antigens with molecular sizes of 34,000 daltons (34 kDa) and 38 kDa were separated from heated cells of a human clinical treponeme strain G7201 and Treponema denticola ATCC 35404, respectively. The rabbit polyclonal antisera against these antigens were produced and examined for their immunological reactions with the two heated antigens or intact spirochetal cells. Immunoblot analysis showed that the 34-kDa protein was also detected in T. denticola ATCC 35404 and ATCC 33520, and the 38-kDa protein was detected only in the two ATCC strains. Immunoelectron microscopy using the two rabbit antisera and protein A-gold complexes demonstrated that the 38-kDa protein antigen was present on the axial flagella of two T. denticola strains, and that the 34-kDa protein was located in the axial flagella of the G7201 cell, but neither in axial flagella nor on outer envelopes of the two ATCC strains cells, suggesting that the native 34-kDa axial flagellar protein of the G7201 strain may be different from that of T. denticola in terms of immunological reactivity.

Longitudinal monitoring of humoral antibody in subjects with destructive periodontal diseases

Fifty-one subjects (16-61 years old) with evidence of prior destructive periodontal disease were monitored clinically and immunologically at bi-monthly intervals for up to 5 yr. Periodontal disease activity, determined as new attachment loss, was detected in 33 of these subjects. Only 4 of 51 subjects failed to show an elevated serum antibody level to any of the 18 subgingival species tested. The antibody level threshold established for periodontally healthy subjects was exceeded most often in diseased subjects with serum antibody to Actinobacillus sp., P. gingivalis, E. corrodens, C. concisus, F. nucleatum and P. intermedia in that order. In general, most serum antibody levels to subgingival species remained relatively consistent for periods as long as 5 yr. However, major increases and decreases in antibody could be detected to at most one or two species in individual subjects. In addition, prolonged, steady increases and decreases in antibody to specific species could be detected in certain subjects. These findings suggest that major changes occurring in serum antibody may reflect fluctuations in the nature of the infection. Differences were observed in the antibody level to specific species when subjects were divided into subsets on the basis of clinical criteria. These included high levels of antibody to A. actinomycetemcomitans Y4 in LJP and RPP subjects and to A. actinomycetemcomitans 29523 in LJP and GJP subjects.

Identification of spirochetes related to Treponema pallidum in necrotizing ulcerative gingivitis and chronic periodontitis

BACKGROUND

Spirochetes are commonly associated with periodontal disease, but it is not known whether these treponemes are pathogenic or merely opportunistic. We sought to determine whether spirochetes present in periodontal disease share antigens thought to be unique to spirochetes that are known pathogens.

METHODS

We examined dental plaque from 24 healthy subjects, from ulcerative sites in 17 patients with ulcerative gingivitis, and from areas of involvement in 19 patients with chronic periodontitis, using an immunocyto-chemical technique with monoclonal antibodies against pathogen-specific determinants on 47-kd and 37-kd molecules from Treponema pallidum subspecies pallidum. Serum was tested against T. pallidum by immunoblotting and by serologic assays for syphilis.

RESULTS

Spirochetes with a pathogen-specific epitope on a 47-kd molecule were not found in plaque samples from any of the 24 healthy subjects, but they were identified in plaque samples from 11 of 17 patients with ulcerative gingivitis (P less than 0.001) and from 10 of 19 patients with periodontitis (P less than 0.01). Monoclonal antibodies directed against a 37-kd molecule reacted with spirochetes in plaque samples from 1 of 14 controls, from all 11 patients with gingivitis from whom samples could be obtained (P less than 0.001), and from 14 of 19 patients with periodontitis (P less than 0.001). Five of 18 normal subjects had IgG against 47-kd and 37-kd molecules, but none had IgG against 14-kd or 12-kd molecules from T. pallidum subspecies pallidum. Among 19 patients with ulcerative gingivitis, IgG was identified against 47-kd molecules in 15, against 37-kd molecules in 12, against 14-kd molecules in 4, and against 12-kd molecules in 15.

CONCLUSIONS

The spirochetes found in dental plaque from patients with ulcerative gingivitis or chronic periodontitis have antigens that are thought to be unique to pathogenic treponemes. This close antigenic relation suggests that T. pallidum or a closely related organism may be involved in the pathogenesis of periodontal disease.

Characteristics of hemolytic and hemagglutinating activities of Treponema denticola

Treponema denticola, a suspected periodontal pathogen, was shown to agglutinate and lyse human red blood cells. Both activities were cell-associated, heat-labile, and produced during the exponential growth phase. Hemolytic activity was time-dependent and required incubation at 37 degrees C; further incubation at 4 degrees C increased the hemolysis. Hemagglutination was reduced in the presence of D-glucosamine, EDTA or sodium salicylate, whereas hemolytic activity was affected by calcium chloride, magnesium chloride, EDTA or sodium salicylate. These biological activities may favor a higher concentration of hemin-containing compounds in periodontal sites, and therefore represent additional potential virulence mechanisms.

Specific antibody responses to subgingival plaque bacteria as aids to the diagnosis and prognosis of destructive periodontitis

We have reviewed the recent literature on the humoral immune responses to a variety of subgingival plaque bacterial species in patients with destructive periodontal diseases. We do not feel that the information presently available on the specific antibody responses to proposed pathogens such as Bacteroides gingivalis and Actinobacillus actinomycetemcomitans allows antibody responses to be diagnostic. All control subjects without periodontal destruction have antibodies to candidate pathogens but the generally higher levels in patients are not sufficiently elevated to be diagnostic. Nor can they be used to predict the initiation of disease or the onset of new episodes of destruction where disease had previously occurred. Successful treatment of patients may lead to lower levels of antibodies to some organisms, including possible pathogens, and thus support a given species in the aetiopathogenesis of disease. It appears that unsuccessful treatment may be accompanied by continuing high antibody levels to some organisms and further studies may enable this observation to be used to monitor therapy. There is some evidence from serological studies that each destructive episode may be induced by a different bacterial species or consortium. The start of studies using single antigens and the techniques of molecular biology will provide not only antibody-based diagnostic methods but also allow us to determine which bacterial antigens are virulence factors and thus the role of the antibody responses, whether protective or damaging, in the periodontal diseases.

Cell-mediated and humoral immune response in diabetic patients with periodontitis

Cell-mediated and humoral immune responses were assessed in 50 patients with type II or non-insulin-dependent diabetes mellitus and 50 nondiabetic patients with periodontitis. The values were compared with those of 50 age and sex-matched control subjects. The cell-mediated immunity assessed by enumerating the total and high-affinity rosette-forming cells of the patient did not show any significant variation from that of the normal control subjects. The humoral immune response was assessed by estimating serum immunoglobulins G, A, M, D, and E by single radial immunodiffusion. Except IgD, all other immunoglobulins were found to be elevated significantly in both diabetic and nondiabetic subjects. The alteration in humoral immune response may be the cause or the effect of periodontitis. The defective host response reported in diabetic patients may be responsible for the increased incidence of periodontitis in diabetic patients as compared to nondiabetic patients.