Reaction of human sera from juvenile periodontitis, rapidly progressive periodontitis, and adult periodontitis patients with selected periodontopathogens

The role of periodontitis-associated bacteria in Alzheimer's disease: A narrative review

Alzheimer's disease causes memory loss and dementia in older adults through a neurodegenerative mechanism. Despite the pathophysiological clarification of this cognitive disorder, novel molecular and cellular pathways should be identified to determine its exact mechanism. Alzheimer's disease (AD) is pathologically characterized by senile plaques comprising beta-amyloid and neurofibrillary tangles (NFTs) formed by hyperphosphorylated tau as a microtubule-associated protein with a key role in the pathogenesis of AD. Periodontitis through inflammatory pathways is a risk factor for deteriorating cognitive impairment in AD patients. Poor oral hygiene coupled with immunocompromised status in older adults causes periodontal diseases and chronic inflammations through an oral bacterial imbalance. Toxic bacterial products, including bacteria themselves, can reach the central nervous system through the bloodstream and evoke inflammatory responses. The present review was conducted to investigate relationships between AD and periodontitis-involved bacteria as a risk factor.

Fusobacterium nucleatum: a commensal-turned pathogen

Fusobacterium nucleatum is an anaerobic oral commensal and a periodontal pathogen associated with a wide spectrum of human diseases. This article reviews its implication in adverse pregnancy outcomes (chorioamnionitis, preterm birth, stillbirth, neonatal sepsis, preeclampsia), GI disorders (colorectal cancer, inflammatory bowel disease, appendicitis), cardiovascular disease, rheumatoid arthritis, respiratory tract infections, Lemierre's syndrome and Alzheimer's disease. The virulence mechanisms involved in the diseases are discussed, with emphasis on its colonization, systemic dissemination, and induction of host inflammatory and tumorigenic responses. The FadA adhesin/invasin conserved in F. nucleatum is a key virulence factor and a potential diagnostic marker for F. nucleatum-associated diseases.

Serum IgG antibody response to periodontal pathogens in minority populations: relationship to periodontal disease status and progression

Differences in periodontal disease prevalence, severity, subgingival microflora and host immune response have been reported for various ethnic/racial groups, which implies that risk factors for destructive periodontal disease progression may also vary in these populations. As it is possible that these differences may be due to confounding variables other than ethnicity/race, we have measured serum IgG antibody response to six periodontal pathogens, and compared these data with microbiological, clinical and demographic parameters in three urban minority populations. The study population consisted of 23 Asiatic, 48 African-American and 37 Hispanic subjects, who were resident in the greater New York region. Clinical indices that were recorded included pocket depth, attachment level, gingival erythema, bleeding upon probing, suppuration and supragingival plaque. Attachment level measurements were taken twice at each visit, and the difference between the means of pairs of measurements taken at baseline and two months later was used to determine disease progression. Subgingival microbiological species were identified and enumerated using DNA-DNA checkerboard hybridization. Serum IgG antibody levels to Actinobacillus actinomycetemcomitans serotyopes a and b, Bacteroides forsythus, Campylobacter rectus, Porphyromonas gingivalis and Prevotella intermedia were measured by enzyme-linked immunosorbant assay (ELISA). Mean serum IgG antibody to P. gingivalis was found to be higher in the African-American group, while IgG antibody to B. forsythus was lower in the Hispanic group. However, the African-American group also had greater mean probing depth, attachment loss, number of missing teeth and numbers of individuals within the unskilled occupational group. When the data were analyzed by occupational status, mean serum IgG antibody to P. gingivalis increased from professional to skilled to unskilled groups. For the entire study population, prior disease and subsequent attachment loss were associated with elevated serum IgG antibody to P. gingivalis. Increasing pocket depth, attachment level, gingival erythema and age were also positively correlated with serum IgG antibody to P. gingivalis, but not with serum IgG antibody to the other five subgingival species. No correlation was found between whole-mouth bacterial levels and homologous serum IgG antibody levels. These results suggest that elevated serum IgG antibody to P. gingivalis reflects destructive periodontal disease status, and may be considered a risk factor for disease progression in these ethnic/racial populations. In addition, although differences in serum IgG antibody profiles to subgingival species were found among the three ethnic/racial groups, environmental and socioeconomic variables may have a greater influence on serum IgG antibody levels in these populations.

Identification and characterization of B-cell epitopes of a 53-kDa outer membrane protein from Porphyromonas gingivalis

We have previously reported that Porphyromonas gingivalis FDC 381 possesses a 53-kDa protein antigen (Ag53) on its outer membrane that evokes a strong humoral immune response in many patients with periodontal disease and that the humoral immune responses to Ag53 differ greatly among patients. To understand how the individual humoral immune system against Ag53 was determined, the regions of Ag53 recognized by specific antibody (B-cell epitopes) and dominant subclasses of serum immunoglobulin G (IgG) against major B-cell epitopes were examined by enzyme-linked immunosorbent assay. This study used sera from six patients with periodontitis, which all reacted strongly with sonic extracts of P. gingivalis 381 and with purified Ag53, and sera from six periodontally healthy children, which did not react with either sonic extracts of P. gingivalis 381 or Ag53. The epitopes were identified using synthetic 5-residue overlapping decapeptides covering the entire Ag53. Thirteen of 89 synthetic decapeptides showed a strong reaction with sera from the periodontal patients, but no reaction with those from the healthy children. Four peptides of 13 exerted different immune responses among patients. Furthermore, restriction analyses of the highly antigenic regions revealed that three sequences, RAAIRAS, YYLQ and MSPARR, were identified as major B-cell epitopes. Additionally, these epitopes were recognized mainly by the IgG2 isotype. These data suggest that the difference of B-cell epitopes might influence individual differences in antibody titer against Ag53 and also that the epitopes recognized commonly by multiple antibodies are quite valuable for peptide vaccine development against P. gingivalis infection.

Identification of an antigenic protein Pga30 from Porphyromonas gingivalis W50

Porphyromonas gingivalis is a black-pigmented, gram-negative bacterium that has been implicated as a major pathogen in the development of adult periodontitis. In an approach to identify a P. gingivalis antigen uniquely seroreactive with healthy subjects, we produced a surface and periplasmic extract of P. gingivalis, separated that extract into 36 fractions using anion-exchange chromatography and screened each fraction for reactivity in an enzyme-linked immunosorbent assay (ELISA) using sera from eight periodontitis patients and eight age- and sex-matched healthy controls. All of the diseased subjects harboured subgingival P. gingivalis by DNA probe analysis and exhibited similar seroreactivity profiles to the anion exchange fractions. However, only two of the healthy subjects (C10 and C15) were seroreactive with the fractions. The highest reactivity for all the seropositive subjects was with the same anion-exchange fractions 13-15. The anion exchange fraction (14) with the highest seroreactivity was subjected to gel filtration chromatography, and fraction 22 from this chromatography exhibited the highest reactivity with all the seropositive subjects. However, fraction 27 was found to be uniquely seroreactive with healthy subject C10, as it was not recognized by sera from any of the diseased or the other healthy subjects. This fraction was further purified by reversed-phase high-pressure liquid chromatography and shown to contain a 30-kDa protein as determined by SDS-PAGE. Control subject C10 had no pocket depths greater than 3 mm and no sites that bled on gentle probing; however, P. gingivalis was detected in subgingival plaque samples at a level of 10(5)-10(6) cells per site in two of the ten sites sampled. This subject was also unusual in that he exhibited a seroreactivity profile similar to that of diseased subjects, which was not characteristic of the healthy control subjects. The unique reactivity of the 30-kDa antigen, designated Pga30, with subject C10 serum was confirmed in a Western blot with the purified antigen. N-Terminal sequence analysis of Pga30 produced a single, unambiguous protein sequence confirming the purity of the protein. A search of the database using the N-terminal sequence obtained did not reveal any significant sequence similarity. In conclusion, we have identified a P. gingivalis antigen that was uniquely reactive in an ELISA and Western blot with serum from a subject with no clinical signs of periodontitis who harbored P. gingivalis in subgingival plaque.

"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.

A rapid DNA probe method for detection of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans

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 (chi2 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 (chi2 test: P <0.001). The detection rate of A. actinomycetemcomitans was highest in teenagers. At shallow periodontal pocket sites (PD < or =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 (chi2 test: P <0.001).

CONCLUSIONS

The rapid DNA probe method appears promising as an efficient tool for rapid clinical detection of periodontopathic bacteria.

Early-onset periodontitis

In 1993, the 1st European Workshop on Periodontology explicitly recognized that there was insufficient knowledge to differentiate truly different forms of periodontal disease from differences in the presentation/severity of the same disease. In spite of recent progress in our understanding of periodontal diseases, the issue is far from having been resolved. Classification of periodontal diseases, therefore, remains based upon the definition of specific clinical syndromes. Early-onset periodontitis (EOP) is one such syndrome and comprises a group of pathological conditions leading to loss of periodontal tissues early in life. The notion that classifies periodontitis syndromes as "early-onset" or "adult" is primarily epidemiological in nature and is based on the observation that periodontitis is rather infrequent in children and young adults. Nevertheless, considerable epidemiological evidence indicates that periodontitis does affect children and young adults to a level of severity that may lead to premature exfoliation of primary and/or permanent teeth. Clinical presentation of periodontitis early in the life of an individual is thought to indicate that the etiologic agents have been able to cause considerable tissue damage over a relatively short period of time. It also implies either infection with highly virulent bacteria and/or a highly susceptible subject. The purpose of this review is to discuss the criteria generally utilized to classify EOP, provide the rationale to designate EOP as a distinct disease entity, and to review the evidence justifying a subclassification into particular subgroups of EOP.

Protective effect of serum antibodies against a 110-kilodalton protein of Actinobacillus actinomycetemcomitans following periodontal therapy

Thirty-four adult patients with untreated periodontitis were randomly assigned to receive full mouth scaling alone or scaling with an adjunctive antimicrobial therapy, both followed by supportive periodontal therapy. At 24 months, specific serum immunoglobulin A (IgA), IgG and IgG subclass antibody reactivities against a 110-kDa protein of Actinobacillus actinomycetemcomitans were assessed by Western blot. In patients harboring A. actinomycetemcomitans intraorally, the IgG4 antibody reactivity against the 110-kDa protein of A. actinomycetemcomitans was associated with significantly increased survival rates of teeth and of sites not exhibiting 2 mm or more of probing attachment loss. The same trend was found for IgG3 and IgG2 antibody reactivities, but it was statistically insignificant. No association with clinical treatment outcome was observed for IgA, IgG and IgG1 antibody reactivities. The results indicated that systemic IgG4 antibody reactivity against the 110-kDa protein of A. actinomycetemcomitans may have a protective effect against periodontal disease progression in patients harboring A. actinomycetemcomitans and receiving periodontal therapy.

Function of anti-Porphyromonas gingivalis immunoglobulin classes in immunized Macaca fascicularis

We previously reported that Macaca fascicularis immunized with formalin-killed Porphyromonas gingivalis were protected against the bone loss of periodontitis. To examine mechanisms of protection, we determined specific immunoglobulin G (IgG), IgM and IgA titers and opsonic capacities of sera from immunized and control animals. Serum IgG and IgA titers to P. gingivalis appeared early and persisted throughout the 36-week observation period. IgM titers were elevated until 6 to 12 weeks and then decreased through week 36. A significant association was observed between peak IgM titers prior to ligature placement and protection against bone loss (measured at week 30). In control monkeys, no significant IgG, IgA or IgM titers were seen. In sera from immunized animals, significant opsonic capacity was seen by 6-12 weeks and persisted throughout the study. In contrast, control sera showed only low opsonization capacity. Anti P. gingivalis antibody titers in purified IgG, IgA and IgM fractions were determined by enzyme-linked immunosorbent assay, and opsonic activity was demonstrated only in the IgG fraction.

The description of a unique population with a very high prevalence of localized juvenile periodontitis

The reported prevalence of localized juvenile periodontitis (LJP) amongst teenagers and young adults varies greatly. The etiology of LJP has been related to Actinobacillus actinomycetemcomitans (Aa), and it has also been suggested that there may be a transmission of Aa within families resulting in the familial distribution of the disease. This study describes the high prevalence of LJP in adolescents, 12-20 years of age, from a group of nuclear families living and functioning in a closed, closely knit community. The survey was carried out on a population of teenagers that had attended the same school and their siblings. All students attending that school and their siblings were examined. They were given a periodontal examination and a questionnaire relating to their demographic details and their personal oral hygiene habits. The periodontal examination was limited to the incisors and first molar teeth. Plaque index (PlI), gingival index (GI), the presence or absence of bleeding on probing (BOP), probing pocket depth (PPD) and recession were measured. All patients having at least two of the examined sites with probing pocket depth > or =5 mm or one site > or =6 mm were considered as possible sufferers from LJP and had a full mouth periapical radiographic survey carried out using a paralleling technique to confirm the diagnosis. At the sites with probing pocket depth > or =5 mm, a Shei ruler was used to measure the % of the root coronal to the alveolar bone. A cut off point of > or =20% was used as a measure of true bone loss confirming the clinical diagnosis of LJP. 86 individuals from 30 families comprised the population of interest. There were 44 males and 42 females with a mean age of 14.7+/-2.3. Of the 86 individuals examined, 33 individuals from 15 families were diagnosed as having LJP (38.4%). None of the individuals examined showed any evidence of the generalized form of juvenile periodontitis. The mean age of the LJP patients was 15+/-2.3 yrs. with a 1:1.75 male to female ratio. Except for 2 pairs of families with genetic ties, no familial connections could be traced between the different nuclear families affected by LJP despite repeated and intensive questioning. There were no significant differences in the PlI and the GI between the groups while the LJP group had significantly higher BOP, PPD and PAL than the non-LJP group. These finding strongly suggest an environmental influence in the etiology of the disease.

Periodontal status and serum antibody responses to oral microorganisms in Sjögren's syndrome

Sjögren's syndrome is an autoimmune disease characterized by keratoconjunctivitis sicca and xerostomia. Rapid bacterial plaque accumulation occurs in Sjögren's syndrome patients due to decreases in salivary flow rate. The purpose of this study was to evaluate the periodontal status of patients with Sjögren's syndrome and evaluate serum antibody responses to selected oral microorganisms, including major periodontopathogens, compared to healthy controls. Seventeen Sjögren's syndrome patients and 14 healthy subjects were included in the study. Plaque (PL), sulcular bleeding (SBI), periodontal index scores (PI), probing depths (PD), and total number of teeth were recorded. An ELISA was used to determine the serum IgG antibody level to a panel of 13 oral microorganisms. Significantly higher PL, SBI, PD, and PI scores, as well as an increased number of lost teeth were observed in patients with Sjögren's syndrome compared to healthy subjects (P <0.0001). Antibody levels to Streptococcus oralis were significantly lower in Sjögren's syndrome patients than controls (P <0.0002). These patients exhibited significantly elevated antibody levels to Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis compared to controls (P <0.006 to 0.0004). Our findings indicate that Sjögren's syndrome patients have established periodontal disease and serum antibody responses to oral microorganisms previously identified as periodontopathogens in systemically healthy subjects. These results suggest that Sjögren's syndrome may affect bacterial colonization in plaque and contribute to increased periodontal disease in this compromised population.

Molecular size distribution analysis of human gingival proteoglycans and glycosaminoglycans in specific periodontal diseases

In order to determine the molecular-size distribution of gingival proteoglycans (PGs) and glycosaminoglycans (GAGs) both in periodontal health and disease states, gingival tissues were obtained from patients with early onset periodontitis (EOP) and adult periodontitis (AP) and also from periodontally healthy subjects. Gel filtration chromatography of gingival PGs revealed different profiles for periodontally diseased and healthy gingiva. Healthy gingiva was mainly composed of high-molecular size proteins and PGs, while diseased gingival tissue presented a decrease in high-molecular size PG forms and a shift towards low-molecular size proteins and PGs. This indicates the degradation of PG macromolecules during periodontal disease activity. Furthermore, this shift towards low-molecular size forms was more intense in EOP patients when compared to AP patients. Gel filtration of gingival GAGs also demonstrated depolymerization of GAGs, with low-molecular size GAGs being more intense in periodontally diseased gingiva, while healthy gingival GAGs profile was mainly composed of high-molecular size GAGs. Similar to the profile of gingival PGs, low-molecular size gingival GAGs were more prominent in gingival tissue from patients with EOP. These findings suggest that both PGs and GAGs, essential components of the extracellular matrix (ECM), are depolymerized during periodontal disease activity, which is more prominent in EOP. Since the basic feature of periodontal disease is matrix degradation, ECM components, more specifically PGs and GAGs, are likely to provide valuable information for a better understanding of periodontal disease activity.

Attachment loss and serum antibody levels against autologous and reference strains of Actinobacillus actinomycetemcomitans in untreated localized juvenile periodontitis patients

Immunological data have been suggested to be a potential tool in the diagnosis, classification and monitoring of periodontal diseases. However, the role of circulating antibodies in periodontal patients is poorly understood. Patients suffering from localized juvenile periodontitis (LJP) are often reported to show high titers of serum IgG antibodies against Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans), but several affected patients do not. Most studies use well-known reference strains of the bacterium for testing against the patients' sera. The aim of the present investigation was to study the relationship between serum IgG antibody levels to autologous A. actinomycetemcomitans strains and clinical attachment loss (CAL). In addition, we wanted to assess the patients' serum titers against 4 well-known reference strains of the bacterium as well as their general potential immunoglobulin response. Intravenous blood samples were taken from 23 LJP patients and 10 healthy individuals, and autologous A. actinomycetemcomitans strains were cultured from 18 of the LJP patients. CAL was measured at 4 different sites around all present teeth and assessed as a % of teeth with at least 1 site moderately > or = 2 < 5 mm) or severely (> or = 5 mm) involved. An enzyme-linked immunosorbent assay (ELISA) was performed to evaluate the serum titers of IgG antibodies to A. actinomycetemcomitans antigens. No significant correlation was found between serum IgG antibody titers to autologous strains and CAL. However, there was a trend that low responders had more moderately affected teeth than had high responders and patients with undetectable A. actinomycetemcomitans levels, which is in agreement with a hypothetically protective role of the antibodies. The total counts of immunoglobulin assessed in all participants showed that the predominant class was IgG and the reference group displayed significantly less (p < 0.05) IgG and IgG1 counts than the LJP patients. Both the reaction pattern against reference and autologous strains varied widely. We conclude that the specific antibody response against A. actinomycetemcomitans shows a weak correlation to clinical attachment levels in LJP patients.

The relationship between colonization and haemagglutination inhibiting and B cell epitopes of Porphyromonas gingivalis

Passive immunization with the monoclonal antibody 61BG1.3 selectively prevents colonization by Porphyromonas gingivalis in humans (Booth V, Ashley FP, Lehner T. Infect Immun 1996; 64:422-7). The protective MoAb recognizes the beta component of the RI protease of P. gingivalis which is formed by proteolytic processing of a polyprotein precursor termed PrpR1. This subunit is both a haemagglutinin and an antigen which is recognized by sera from patients with periodontitis. In this study the relationship was investigated between a colonization epitope which is recognized by the MoAb 61BG1.3, a haemagglutinating and B cell epitope which are recognized by sera from patients with periodontitis. B cell epitopes were mapped by Western blotting with a series of truncated recombinant polypeptides spanning the adhesion domain within residues 784-1130 of PrpR1 and by ELISA using a panel of synthetic peptides spanning the same sequence. The epitope which is recognized by the protective MoAb was mapped within residues 907-931 of PrpR1, while serum responses of patients were directed predominantly to the adjacent carboxy-terminal sequence within residues 934-1042. The haemagglutinating epitope was mapped to residues 1073-1112. In view of our previous findings that the MoAb 61BG1.3 prevents colonization of P. gingivalis in vivo and inhibits haemagglutination, these two epitopes may be in proximity in the native protein. Active or passive immunization strategies which target the protective or haemagglutinating epitopes of the adhesion domain of PrpR1 may provide a means of preventing infection with P. gingivalis.

Estimation of serum antibody to subgingival species using checkerboard immunoblotting

Measurement of serum antibody to subgingival bacterial species has been useful in discriminating possible periodontal pathogens and in assessing the host's immune response to subgingival species. An immunoassay system was developed to measure the level of serum antibody to multiple subgingival species in multiple serum samples on a single nitrocellulose membrane. The principle steps of the assay are the following: 1) binding of antigens from bacterial preparations and protein A in parallel lanes on nitrocellulose membranes; 2) incubation of known concentrations of human immunoglobulin as well as various dilutions of serum from patients in lanes perpendicular to the antigen lanes; 3) incubation of the membrane with a peroxidase-conjugated second antibody; 4) detection of positive reactions by enhanced chemiluminescence. Emitted light was captured on a photographic film in which the positive reactions appeared as squares at the intersections of antigens with appropriate antibody. Antibody was quantified using a laser densitometer to compare the signal intensity of unknown samples with the ones generated by known amounts of human immunoglobulin captured on the same membrane. The assay permitted simultaneous screening and/or quantification of antibody in as many as 45 serum samples against up to 45 bacterial species. The mean and standard error of the coefficients of variation for replicates within an assay averaged 7.3 +/- 2.3%. Coefficients of variation of the assay run on different days for serum antibody to a range of subgingival species averaged 10.1 +/- 2.1%. Checkerboard immunoblotting is a simple and rapid immunoassay to permit quantification and/or screening of antibody to multiple subgingival species or antigens in multiple serum samples.

Recognition of antigenic epitopes in lipopolysaccharide and protein from Actinobacillus actinomycetemcomitans by serum antibodies in untreated rapidly progressive periodontitis patients

Actinobacillus actinomycetemcomitans has been associated with early-onset periodontitis, including the localized juvenile and rapidly progressive forms. The immunodominant antigens of A. actinomycetemcomitans recognized by rapidly progressive periodontitis patients remain unidentified. Sera from 22 patients with rapidly progressive periodontitis and 20 periodontally normal subjects were tested by enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G antibodies to whole-cell sonicate, protein, purified lipopolysaccharide and lipopolysaccharide fractions of A. actinomycetemcomitans. The median titers of rapidly progressive periodontitis patients and control subjects to whole-cell sonicate were 25.0 and 14.5 ELISA units, respectively (not significantly different). Binding of antibody from patient sera occurred to both the lipopolysaccharide and the protein fractions, with greater binding to lipopolysaccharide than to protein. We show for the first time that patient sera contain antibodies that bind specifically to antigenic epitopes in lipid A and in the core carbohydrate of lipopolysaccharide that were previously considered to be inaccessible and unavailable, as well as to epitopes in the O side chains. Sera manifesting antibody titers 2-fold or greater than the median titer for control sera were judged to be seropositive. More patients were seropositive for lipid A than for any of the other antigen preparations studied, and the median titer for patient sera to lipid A but to none of the other purified lipopolysaccharide fractions was significantly elevated relative to control values. Of 22 patients, 10 were seropositive to whole-cell sonicate, 7 to protein, 8 to lipopolysaccharide, 7 to the high-molecular-weight lipopolysaccharide-polysaccharide fraction rich in O side chains, and 16 to lipid A. The core carbohydrate did not adhere to the test plate surface, and this precluded ELISA measurements. However, when the core carbohydrate was used in the ELISA inhibition assay, it reduced antibody binding to lipopolysaccharide-coated plates by up to 45%, thereby demonstrating antibody binding to core carbohydrate. The core carbohydrate fraction from the Re mutant of Salmonella minnesota known to contain no O-side chains also inhibited binding of specific antibody to plates coated with A actinomycetemcomitans lipopolysaccharide. Overall, there was extreme variation in responses among patients to the various antigen preparations, with no single pattern dominating. Lipopolysaccharide and its components appear to be the immunodominant epitopes, since most rapidly progressive periodontitis patients are seropositive for lipopolysaccharide and/or its components and they have titers relative to those for proteins.

Bacterial adherence to guided tissue regeneration barrier membranes exposed to the oral environment

Microbial colonization of barrier materials used in guided tissue regeneration (GTR) is known to adversely affect treatment outcomes. The purpose of this study was to compare the rate at which 11 commonly-occurring oral bacteria species colonize three different barrier materials (collagen, expanded polytetrafluoroethylene, and polylactic acid). The study group consisted of 10 systemically healthy individuals with no history of periodontal disease and absence of antimicrobial therapy within the previous 3 months. In each patient, 4 teeth per quadrant (P1, P2, M1, M2) were selected and 3 teeth were randomly assigned as test teeth while the remaining tooth acted as a control site (i.e., natural colonization of the tooth surface). These teeth were then randomly assigned to receive one of the three barrier types (i.e., each patient received 4 barriers of each type, 1 per quadrant). A 2 x 5 mm piece of barrier material was positioned over the oral surface of the buccal marginal gingiva and secured with an external sling suture. With oral hygiene procedures suspended, one barrier of each type was collected at 1, 3, 7, and 14 days. Slot immunoblot assay demonstrated that all species types (A. actinomycetemcomitans, A. viscosus, B. melaninogenicus, F. nucleatum, P. gingivalis, P. intermedia, S. mutans, S. sanguis, Selenomonas sputigena, T. denticola, and T. vincentii) were present. Semi-quantitative scoring (scale 0 to 3) of slot blot results and analysis by chi-square ratio and Pearson correlation test indicated that while total bacteria adherence increased over time (P < 0.05), the 3 barrier types and the control sites did not differ in numbers or species of colonizing bacteria detected per time point. These results suggest that under these experimental conditions the barrier materials tested do not differ in bacteria adherence or antimicrobial properties.

Antibody reactive with Actinobacillus actinomycetemcomitans leukotoxin in early-onset periodontitis patients

The objective of this study was to determine whether a relationship exists between antibody reactive with the Actinobacillus actinomycetemcomitans leukotoxin and the severity of periodontal disease. Serum concentrations of antibody reactive with the leukotoxin were determined for 119 early-onset periodontitis patients and 59 non-periodontitis subjects using limiting dilution analysis on Western blots. Immunoglobulin G (IgG) antibody reactive with the A. actinomycetemcomitans leukotoxin ranged from undetectable to 29 micrograms/ml (mean = 3.13 +/- 0.97 micrograms/ml for the generalized early-onset periodontitis and 2.17 +/- 0.86 micrograms/ml for the localized juvenile periodontitis patients vs 0.32 +/- 0.24 ng/ml for 59 non-periodontitis controls), and the dominant subclass was IgG1. Analysis of the relationship between antibody reactive with A. actinomycetemcomitans sonicate, A. actinomycetemcomitans leukotoxin and attachment loss patterns indicates that seropositive generalized early-onset periodontitis patients had decreased attachment loss compared with patients lacking this antibody. The statistical relationship appeared to be stronger for the sonicate than the purified leukotoxin. These data suggest that antibody reactive with A. actinomycetemcomitans leukotoxin may be protective in early-onset periodontitis, but given that the sonicate appeared better than the leukotoxin alone, it is not likely that leukotoxin is the only antigen of importance to host defense.

Immunoglobulin allotypes and immunoglobulin G subclass responses to Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in early-onset periodontitis

The present study was performed to estimate the observed frequencies of the immunoglobulin heavy-chain (Gm) and light-chain (Km) allotypes among patients with early-onset periodontitis (EOP) and their effect on the IgG2 subclass responses against Actinobacillus actinomycetemcomitans Y4 and Porphyromonas gingivalis 381, respectively. Sixty-nine EOP patients, including 11 with localized juvenile periodontitis (LJP), 19 who had LJP, 15 with LJP-rapidly progressing periodontitis (RPP), and 24 with RPP, were examined for the Gm and Km allotypes by a hemagglutination inhibition test. Levels of immunoglobulin G2 (IgG2) antibodies against the two organisms were determined by enzyme-linked immunosorbent assay. Fifty race- and age-matched, periodontally healthy subjects were also included as a control group. The observed frequencies of the Gm haplotype afnb and Km(1) were significantly higher in the RPP and LJP groups, respectively. The G2m(n)+ group of those with RPP and the Km(1)+ group of those with LJP had significantly higher levels of IgG2 antibodies to A. actinomycetemcomitans and P. gingivalis, respectively. The results indicate that linkage disequilibrium of the G2m(n) locus in RPP patients or the Km(1) locus in LJP patients may be associated with high IgG2 antibody responses to the respective bacteria. It was reasoned that the IgG2 antibody responses are associated with the immunoglobulin allotypes. The function of IgG2 antibodies in their reaction to different bacterial antigens may be interpreted as either protective or nonprotective in the two different types of EOP (i.e., LJP and RPP).

Taxonomy, biology, and periodontal aspects of Fusobacterium nucleatum

The pathogenic potential of Fusobacterium nucleatum and its significance in the development of periodontal diseases, as well as in infections in other organs, have gained new interest for several reasons. First, this bacterium has the potential to be pathogenic because of its number and frequency in periodontal lesions, its production of tissue irritants, its synergism with other bacteria in mixed infections, and its ability to form aggregates with other suspected pathogens in periodontal disease and thus act as a bridge between early and late colonizers on the tooth surface. Second, of the microbial species that are statistically associated with periodontal disease, F. nucleatum is the most common in clinical infections of other body sites. Third, during the past few years, new techniques have made it possible to obtain more information about F. nucleatum on the genetic level, thereby also gaining better knowledge of the structure and functions of the outer membrane proteins (OMPs). OMPs are of great interest with respect to coaggregation, cell nutrition, and antibiotic susceptibility. This review covers what is known to date about F. nucleatum in general, such as taxonomy and biology, with special emphasis on its pathogenic potential. Its possible relationship to other periodontal bacteria in the development of periodontal diseases and the possible roles played by OMPs are considered.

Shared antigens of Porphyromonas gingivalis and Bacteroides forsythus

Periodontitis in humans is caused by a group of predominantly gram-negative, anaerobic bacteria among which Porphyromonas gingivalis and Bacteroides forsythus are prominent. A similar group is present and presumably plays a similar role in experimental periodontitis in the primate Macaca fascicularis. Nevertheless, immunization using a vaccine containing only killed P. gingivalis suppresses the progress of experimental periodontitis in M. fascicularis. We investigated the hypothesis that gram-negative periodontopathic bacterial may share antigens, and immunization with one species may induce antibodies reactive with other gram-negative species. Using enzyme-linked immunosorbent assay (ELISA), Western and dot immunoblots with nonabsorbed and absorbed and immune and preimmune sera we show that monkeys immunized with P. gingivalis produce antibodies reactive not only with antigens of P. gingivalis but also with those of B. forsythus. Similarly, rabbits immunized with P. gingivalis or with B. forsythus produce antibodies that react with antigens of both bacteria. Cross-reactive antibodies bind to epitopes in lipid A and possibly in core carbohydrate of lipopolysaccharide. Using complexes of lipopolysaccharide with polymyxin B, bovine serum albumin and apolipoprotein A1 specificity of binding was documented. Using sera from monkeys immunized with P. gingivalis, cross-reactivity with Actinobacillus actinomycetemcomitans could not be demonstrated by ELI-SA, although binding to lipopolysaccharide but not to lipid A was demonstrated by Western and dot immunoblots. Antibodies to shared lipopolysaccharide epitopes of periodontopathic bacteria may account, at least in part, for the immune protection observed in immunized monkeys, and shared epitopes may have potential as a vaccine for periodontitis in humans.

Induction of systemic murine B-cell responses by Fusobacterium nucleatum and Porphyromonas gingivalis

The purpose of this study was to examine the antigenic abilities of Fusobacterium nucleatum strain ATCC 25586 and Porphyromonas gingivalis strain W50 black inbred BALB/cABom mice immunized subcutaneously. Furthermore, we aimed to analyze whether the outer membranes (OM) and whole cells (WC) of F. nucleatum or P. gingivalis had an effect on the levels of antibody response and whether a combination of both could either enhance or suppress the B-cell response. A single-cell assay, solid-phase enzyme-linked immunospot (ELISPOT), was used to analyze the splenic B-cell response (immunoglobulin A (IgA), IgG and IgM). Enzyme-linked immunosorbent assay (ELISA) and immunoblotting were used to verify the specific antibody response in the sera. A statistically significant lower level of spontaneous antibody production was observed in the group immunized with P. gingivalis OM compared with groups immunized with F. nucleatum and saline. The specific antibody titers measured by ELISA indicated that the bacterial preparations were able to induce IgG and IgM response. The preparations containing P. gingivalis OM induced higher humoral response than the preparations containing P. gingivalis WC, but for F. nucleatum such a difference was not observed. The prominent proteins revealed had apparent molecular masses of 40 kDa for F. nucleatum and 115, 55-56 and 43 kDa for P. gingivalis; whereas the immunoreactive proteins were 70, 65 and 40 kDa for mice immunized with F. nucleatum and 115, 55-56, 43 and 33-34 kDa for mice immunized with P. gingivalis. Quantitative analysis of B-cell response at the single cell level with ELISPOT revealed that some component(s) of P. gingivalis OM may have a suppressive ability on splenocytes incubated for a short time.

Taxonomy, biology, and periodontal aspects of Fusobacterium nucleatum

The pathogenic potential of Fusobacterium nucleatum and its significance in the development of periodontal diseases, as well as in infections in other organs, have gained new interest for several reasons. First, this bacterium has the potential to be pathogenic because of its number and frequency in periodontal lesions, its production of tissue irritants, its synergism with other bacteria in mixed infections, and its ability to form aggregates with other suspected pathogens in periodontal disease and thus act as a bridge between early and late colonizers on the tooth surface. Second, of the microbial species that are statistically associated with periodontal disease, F. nucleatum is the most common in clinical infections of other body sites. Third, during the past few years, new techniques have made it possible to obtain more information about F. nucleatum on the genetic level, thereby also gaining better knowledge of the structure and functions of the outer membrane proteins (OMPs). OMPs are of great interest with respect to coaggregation, cell nutrition, and antibiotic susceptibility. This review covers what is known to date about F. nucleatum in general, such as taxonomy and biology, with special emphasis on its pathogenic potential. Its possible relationship to other periodontal bacteria in the development of periodontal diseases and the possible roles played by OMPs are considered.

Purification and characterization of Porphyromonas gingivalis outer membrane antigens

Porphyromonas gingivalis is strongly associated with periodontal disease. Significant titres of specific IgG antibodies to P. gingivalis can be found in healthy individuals and those with periodontitis. In this study, 22 outer membrane antigens ranging from 15.5 to 107.6 kDa were recognized by sera from persons with periodontitis and controls. Serum from individuals with periodontitis showed a significantly higher IgG response to a 31.4-kDa antigen (p < 0.05); serum from those with gingivitis demonstrated a significantly higher response to a 15.5-kDa antigen (p < 0.05). The response to the 15.5-kDa antigen might represent a protective immune response while that to the 31.4-kDa could serve as a marker for disease susceptibility. These two antigens were purified to homogeneity and their N-terminal amino acid sequences determined. The sequences did not correspond to any previously described P. gingivalis antigens. The role of these two antigens in the pathogenesis of periodontal disease remains to be determined.

Immunodominant antigens of Porphyromonas gingivalis in patients with rapidly progressive periodontitis

W studied 4 isolates of Porphyromonas gingivalis, ATCC 33277, 381, A7A1-28, and W50, to identify major cell surface antigens and select the best strain from which to obtain antigen for a test vaccine. Immunoglobulin G (IgG) titers measured by enzyme-linked immunosorbent assay using whole-cell sonicates as antigen were significantly elevated for the sera of 64 rapidly progressive periodontitis patients relative to sera of 30 normal control subjects for each of the 4 strains studied. Western blots were prepared for all 4 strains and developed using sera from 22 patients and 20 control subjects to identify and determine the frequency of antibody-binding components. The intensity of binding by patient sera was greatest for the 75-kDa and 55-kDa components. The 43-kDa component was also widely recognized. Strains ATCC 33277 and 381 appeared to be antigenically similar. Because of the higher serum antibody titers, the larger proportion of seropositive patients and higher frequency of binding to specific protein components in Western blots, our efforts were focussed on strain ATCC 33277. Whole-cell sonicates, proteinase K-digested sonicate, lipopolysaccharide, capsular polysaccharide, and whole-cell protein fractions were prepared and evaluated for antigenic activity. By dot immunoblot, most of the antibody binding activity was found in the whole-cell protein fraction, with much lesser amounts in lipopolysaccharide and none in capsular polysaccharide. The antibody-binding activity was accessible on the cell surface, since 98.9% of P. gingivalis-specific antibody, including antibody binding to the 43-kDa, 55-kDa components on Western blot, was removed by whole-cell adsorption. Furthermore, the 43-kDa and 55-kDa but not the 75-kDa component on intact cells were accessible for labeling with 125I, confirming their cell surface location and accessibility.

Effect of periodontal treatments on serum IgG antibody titers against periodontopathic bacteria

Serum IgG antibody titers to 7 periodontopathic bacteria in periodontitis patients were measured at the 1st visit and after various periodontal treatments with clinically successful improvement, in order to evaluate what kind of factors are associated with changes of serum antibody titers. 20 patients (10 male and 10 female from 23 to 61 years old) with adult, rapidly progressive periodontitis were enrolled in this study. All patients received initial preparation and most of them also underwent surgical procedure. After the treatments, the mean probing pocket depths decreased from 3.72 mm to 1.56 mm. Serum samples were collected from patients at the initial and final examinations. Serum IgG antibody titers against sonicated antigens of Porphyromonas gingivalis FDC 381, Prevotella intermedia ATCC 25611, Prevotella loescheii ATCC 15930, Fusobacterium nucleatum subspecies nucleatum ATCC 25586, Actinobacillus actinomycetemcomitans FDC Y4, Eikenella corrodens FDC 1073 and Capnocytophaga ochracea # M 12 were determined by enzyme-linked immunosorbent assay. The mean antibody titers to P. gingivalis and P. intermedia decreased significantly after the treatment as compared to their pretreatment levels. The antibody titer to P. gingivalis, especially, decreased in all of the patients examined. A significant relationship was found between the decreased antibody titer to P. gingivalis and the number of teeth which received periodontal surgery, as well as treatment length, and the relationship between the decreased antibody titer to P. intermedia and the number of extracted teeth was also significant. These results suggest that the changes of serum IgG titers against P. gingivalis and P. intermedia are related to the suppression of such pathogens in subgingival plague.

Patterns of antibody response in subjects with periodontitis

Periodontal diseases comprise a heterogeneous group of infections that are difficult to distinguish on a clinical basis alone. The purpose of the present investigation was to group periodontitis subjects according to their elevated serum antibody levels to specific subgingival species. A total of 119 subjects (19-70 years) with evidence of prior periodontal destruction were monitored at 2-month intervals (maximum 8 visits), prior to therapy, using clinical parameters measured at 6 sites per tooth. The probing attachment level was measured twice at each visit, and an increase of > 2.5mm at a site was used to define subjects with progressing disease. Serum samples were obtained from each subject at each visit and the level of antibody determined by enzyme-linked immunosorbent assay to 12 subgingival species. Subgingival plaque samples were taken from the mesial aspect of all teeth in each subject at each visit, and the levels of 14 different subgingival species were determined using a colony-lift method and DNA probes. Subjects were grouped by cluster analysis of their elevated antibody levels using a simple matching coefficient. Ninety-two subjects fell into 9 clusters with 100% similarity; 29 subjects in one cluster group exhibited elevated antibody to none of the test species. Seven subjects in a second cluster group showed elevated antibody to Bacteroides forsythus. Subjects in the other 7 clusters showed elevated antibody to Actinobacillus actinomycetemcomitans serotype a only or in combination with B. forsythus, A. actinomycetemcomitans serotype b, Prevotella intermedia or Porphyromonas gingivalis.(ABSTRACT TRUNCATED AT 250 WORDS)

IgG antibody subclass response to Porphyromonas gingivalis outer membrane antigens in gingivitis and adult periodontitis

Porphyromonas gingivalis is an important oral pathogen with a strong association with adult periodontitis. Significant titers of specific IgG antibodies to P. gingivalis can be found in the sera of both gingivitis and periodontitis patients. Since IgG subclasses have different biological characteristics, the present study dealt with the serum IgG subclass response to outer membrane antigens of P. gingivalis. Western blot analysis of P. gingivalis outer membrane was carried out using 20 adult periodontitis and 20 age- and sex-matched gingivitis patients. Antibodies in sera of both adult periodontitis and gingivitis patients recognized 38 antigen bands, ranging in molecular mass from 11.1 to 161 kDa. IgG2 was the predominant antibody subclass response in both patient groups in terms of the numbers of outer membrane antigens recognized, followed by IgG3, IgG1, and IgG4. More antigens in all IgG subclasses except IgG4 were recognized in adult periodontitis cases. Of the 23 antigens identified by IgG2 antibodies, 9 were recognized predominantly in adult periodontitis and 3 in the gingivitis group. In the IgG1 subclass, 4 antigens were recognized predominantly in the adult periodontitis group while only 1 antigen was recognized significantly more in the gingivitis group. The IgG3 response identified 14 antigens ranging in molecular mass from 11.1 to 61.2 kDa in both groups. Ten antigens were recognized significantly by the adult periodontitis group. The lowest response was seen by IgG4 antibodies, with only 3 antigens of molecular mass 61.2, 52.3, and 38.8 kDa recognized, the latter two significantly in the adult periodontitis group.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical and laboratory studies on a patient with early onset periodontitis and her family members. A case report

Extensive clinical, microbiological, hematological, and immunological studies were performed on a patient with early onset periodontitis (EOP) and two other members of the family. The proband, a 27-year-old female, had early onset periodontitis and a high level of serum rheumatoid factors (RF) with no diagnosable medical disease. Her mother had lost all her teeth at the age of 50 because of advanced periodontitis, while her elder sister was unaffected by periodontitis. Neither the proband's periodontally-affected mother nor her unaffected sister exhibited a detectable level of RF. In this study, we examined: 1) serum immunoglobulin G (IgG) antibody titers against putative periodontal pathogenic bacteria; 2) peripheral neutrophil functions; 3) phenotypic analyses of peripheral lymphocyte subpopulations; and 4) peripheral lymphocyte functions (T cell proliferative activity, ability of cytokine [interleukin (IL)-2, tumor necrosis factor-alpha, interferon-gamma, IL-6 and IL-8] and IgG and IgM productivity). High antibody titers to Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Campylobacter rectus were detected in the sera of the proband, as were high serum antibody titers to P. gingivalis in the mother and to C. rectus in the unaffected sister compared to the non-periodontitis affected subjects. The proband also showed enhanced neutrophil chemotaxis; a high percentage of pan-B cells; and high productivity of IL-6, IgG, and IgM compared to individuals who were not periodontally affected. The mother showed slightly low helper/induced T cells (Th/i) suppressor/cytotoxic T cells (Ts/c) ratios due to the elevated count of Ts/c, and high IFN-gamma productivity compared to control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Spontaneous gingival antibody production to Fusobacterium nucleatum outer membrane in patients with adult periodontitis

The local antibody response to Fusobacterium nucleatum outer membrane (FnOM) was analyzed in patients with adult periodontitis (AP) at the single cell level. Furthermore, we analyzed whether periodontal hygienic treatment could alter the antibody response. The number of IgG- and IgM-producing cells were investigated in gingival samples collected from 20 patients with AP. The patients were divided into 2 groups, before (BT, n = 9) and after (AT, n = 11) periodontal hygienic treatment. Four healthy gingival samples were used as controls. The results obtained showed that local antibody production against FnOM occurred in gingiva of patients with AP, but not in healthy gingiva. The IgG anti-FnOM was the predominant isotype observed. However, there was no statistically significant difference between the BT and AT groups. These results indicate that periodontal hygienic treatment was not sufficient to alter significantly the number of IgG- and IgM-secreting cells present in gingival tissue of AP patients, but it promoted a reduction of IgG anti-FnOM secreting cells. The presence of anti-FnOM antibodies in AP but not in control patients indicates that this bacteria may play a role in the pathogenesis of periodontal disease.

Treatment of subjects with refractory periodontal disease

The aim of the present study was to evaluate the effect of non-surgical periodontal therapy with the adjunct of a selected antibiotic in subjects diagnosed with refractory periodontal disease. 21 subjects were selected for the study; all had a history of periodontal surgery, tetracycline therapy, and regular maintenance by a periodontist. When disease activity was detected, a bacterial sample was taken and a whole plaque susceptibility test was performed. Before the outcome of the susceptibility test the subjects were assigned to either antibiotic or placebo therapy. All subjects received scaling and rootplaning prior to antibiotic or placebo therapy. Based on the susceptibility test, subjects in the antibiotic group were treated either with Augmentin or clindamycin. The results demonstrated that in subjects with refractory periodontal disease there was no significant difference (N.S.) in the proportion of sites losing attachment before and after treatment (11.3% and 12.4%, respectively) over a 2-year post therapy observation period. However, the proportion of sites showing gain of attachment increased from 0.9% before therapy to 5.1% (p = 0.029) following selective antibiotic therapy when combined with scaling and rootplaning. The remainder of sites showed no change between pre- and post-therapy monitoring periods. The progression of attachment loss in the active sites could not be completely stopped over the entire 2-year period. After 12-15 months following therapy, there was a tendency towards new loss of attachment and an increase of pocket depth. However, all 4 subjects treated with placebo drug demonstrated continuous deterioration and had to be retreated. Although the proportion of sites losing attachment decreased from 5.1% to 2.3% (N.S.), the proportion of sites gaining attachment also decreased from 2.0% to 1.0% (N.S.). The results suggest that scaling and rootplaning together with selected antibiotic therapy repeated every 12-15 months may be beneficial for these subjects although it may not completely stop progressive attachment loss.

Serum immunoglobulin G subclass concentrations in periodontally healthy and diseased individuals

Patients with localized juvenile periodontitis (LJP) often have high titers of antibody reactive with the serotype-specific immunodominant carbohydrate antigen of Actinobacillus actinomycetemcomitans serotype b. The vast majority of this A. actinomycetemcomitans serotype b-specific antibody is immunoglobulin G2 (IgG2). The present study was undertaken to determine whether the overall total levels of IgG2 in the sera of LJP patients are elevated. LJP patients and nonperiodontitis (NP) controls matched for age, race (black and white), and gender were studied. Additional controls included patients with adult periodontitis (AP) and patients similar in age to LJP patients but with the more-severe, generalized form of early-onset periodontitis (SP). Sera from over 700 periodontally characterized subjects were examined by using radial immunodiffusion to quantitate IgG2 as well as IgG1, -3, and -4, which were included for comparison. Serum IgG2 levels increased with age, and this was most dramatic around puberty. Black subjects in all periodontal groups had nearly 1 mg more IgG2 per ml than their white counterparts. Serum IgG2 levels were elevated (about 30 to 40%) in LJP patients of both races compared with their age- and race-matched NP controls (P < 0.01). In contrast, SP patients and AP patients had IgG2 levels comparable to their age- and race-matched NP controls. No other IgG subclass concentration correlated with periodontal diagnosis except for IgG3, which was elevated in white LJP patients. We reason that the high levels of serum IgG2 in LJP may be helpful in localizing periodontal destruction.

Early-onset periodontitis in Hispanic-American adolescents associated with A. actinomycetemcomitans

This study examines the frequency of oral disease in an adolescent population, and assesses the relationship to Actinobacillus actinomycetemcomitans. A total of 470 eighth grade students from San Antonio, Texas, were examined clinically for number of teeth, frequency of gingival inflammation, frequency of sites with BOP, and frequency of sites with 3-5 mm pockets, and pockets > 5 mm. The population ranged in age from 12 to 17 yr and was 93% Hispanic. Heavy accumulations of plaque and calculus were frequently observed and were associated with gingival inflammation, as 95.6% of the students exhibited bleeding on probing, and 99.6% of the students presented with at least on quadrant of inflammation upon visual examination. Significantly, 25.7% of the students exhibited early-onset periodontitis (EOP) with 1.7% diagnosed as LJP. Many students exhibited substantial levels of plaque and calculus, but no clinical evidence of loss of attachment. Subjects with periodontitis (EOP or LJP) presented with elevated systemic IgG antibody to A. actinomycetemcomitans serotype b and subgingival plaque samples positive for the microorganism. These results describe the prevalence of EOP/LJP in an adolescent Hispanic population from South Texas. The findings support that A. actinomycetemcomitans may represent a pathogen in periodontitis and while oral health care may be poor, contact with the microorganism appears to be required to initiate disease in this population.

Nucleotide sequence of a Porphyromonas gingivalis gene encoding a surface-associated glutamate dehydrogenase and construction of a glutamate dehydrogenase-deficient isogenic mutant

The nucleotide sequence for a surface-associated protein (A. Joe, A. Yamamoto, and B. C. McBride, Infect. Immun. 61:3294-3303, 1993) of Porphyromonas gingivalis was determined. The structural gene comprises 1,338 bp and codes for a protein of 445 amino acids. The deduced molecular weight of the protein is 49,243. A data base search for homologous proteins revealed significant sequence similarity to the subunit protein of glutamate dehydrogenases (GDHs) isolated from various sources. This protein, which was previously labelled PgAg1, will now be called GDH. Recombinant GDH was purified to homogeneity, and native GDH was partially purified from P. gingivalis. Both preparations exhibited NAD-dependent GDH activity. Intact P. gingivalis and an extract of cell surface components also demonstrated NAD-dependent GDH activity. To help elucidate the role of this protein, an isogenic mutant of P. gingivalis lacking the GDH protein was generated by deletion disruption. Biological characterization of the mutant strain, P. gingivalis E51, demonstrated complete loss of GDH activity. Immunogold bead labelling of intact cells showed that GDH was no longer present on the surface of the bacterial cell. The GDH-negative mutant displayed impaired cell growth, as demonstrated by an increased generation time and an inability to grow to the same cell density as the parent.

Macaca fascicularis as a model in which to assess the safety and efficacy of a vaccine for periodontitis

We have assessed Macaca fascicularis as a potential model in which to test the efficacy and safety of a vaccine for periodontitis. Twenty-eight animals were surveyed and 20 studied in more detail. Clinical periodontal status was assessed, the subgingival microflora analyzed especially for the presence and proportions of Porphyromonas gingivalis and titers and avidities of serum antibodies reactive with P. gingivalis measured. Probing depths ranged from 0.90 mm to 3.80 mm, Gingival Index scores from 0.00 to 4.00 and Plaque Index scores from 0.00 to 3.00. About 40% of sites bled on probing. The animals manifested a subgingival flora characteristic of the anaerobic gram-negative bacteria found in human periodontal pockets, including Actinobacillus actinomycetemcomitans, P. gingivalis, Bacteroides forsythus, Campylobacter rectus, Prevotella intermedia and Fusobacterium nucleatum. P. gingivalis was detected in 70 of 80 samples studied, ranging from 0.01% to 20% of the total flora. Serum antibody reactive with antigens of P. gingivalis was observed in all animals, with titers ranging from 1.0 enzyme-linked immunosorbent assay (ELISA) unit to 25 ELISA units and avidities from 0.10 M to 2.20 M. Antibody titer and maximum percentage of P. gingivalis were inversely correlated, indicating that a humoral immune response may be effective in reducing P. gingivalis overgrowth. M. fascicularis appears to be an excellent model for use in vaccine development.

Immunization against Porphyromonas gingivalis inhibits progression of experimental periodontitis in nonhuman primates

Periodontitis is a common infectious disease in which the attachment tissues of the teeth and their alveolar bone housing are destroyed, resulting in tooth loss. The gram-negative anaerobic microorganism Porphyromonas gingivalis has been closely linked to severe forms of the disease. We show for the first time that immunization of the primate Macaca fascicularis with killed P. gingivalis in Syntex Adjuvant Formulation-M inhibits progression of periodontal tissue destruction.

Subgingival distribution of A. actinomycetemcomitans in periodontitis

This investigation developed an experimental design that (1) detailed the distribution of A. actinomycetemcomitans in subgingival plaque related to the level of serum antibody to this pathogen; (2) used broad based subgingival plaque sampling to allow a definition of the distribution of A. actinomycetemcomitans infection in periodontitis patients; (3) described the distribution of A. actinomycetemcomitans serotypes in patients and within sites; and, (4) assessed how this infection impacted upon local clinical symptoms of disease. We noted a significant positive relationship between the level of IgG anti-A. actinomycetemcomitans antibody and the frequency of teeth infected until nearly 13 teeth demonstrated an infection. Furthermore, the results showed a generally negative relationship between the antibody level and the burden of A. actinomycetemcomitans in the infected sites. Interproximal sites associated with first molar teeth were the predominant sites for subgingival colonization; incisors were also frequently infected in this population. The first molar teeth also exhibited the greatest level of A. actinomycetemcomitans, while the incisors demonstrated a high level of A. actinomycetemcomitans in individual sites. The results clearly indicated the majority of the sites sampled were colonized by a single serotype of A. actinomycetemcomitans. We detected A. actinomycetemcomitans nearly 2 x times more frequently and a significant increase in the proportion of A. actinomycetemcomitans was found in samples obtained from teeth with bleeding on probing. The results also showed a significant trend for both pocket depth and attachment levels to be related to the presence and proportion of A. actinomycetemcomitans in the subgingival plaque. These findings detail the microbiological, immunological and clinical characteristics of a unique subset of periodontitis patients that appear to exhibit disease associated (caused?) with A. actinomycetemcomitans infection irrespective of clinical categorization. The results support a unique distribution of this microorganism in the subgingival ecology that is related to active host immune responses and clinical presentation of the tooth.

Infection by Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans, and antibody responses at different ages in humans

This study examined the serum IgG and IgM responses against Porphyromonas gingivalis and 3 serotypes of Actinobacillus actinomycetemcomitans, and the correlations of these responses with age and homologous infection. A total of 90 individuals were included in this study: 40 subjects with gingivitis, 40 periodontally healthy subjects, and 10 adult periodontitis subjects. The subjects in the gingivitis and periodontally healthy groups were divided into 4 stages based on their physiological age: early childhood, school age, puberty, and adult. In the gingivitis group, there was a positive correlation between increase in age and increase in serum IgG antibody levels against P. gingivalis until puberty. However, no statistically significant difference was found between the puberty stage and the adult stage. The average level of IgG antibodies against A. actinomycetemcomitans in the school age gingivitis group was significantly higher than that in the early childhood gingivitis group for all serotypes (p < 0.01). In serotype c, IgG antibody levels in the school age gingivitis group were significantly higher than in the early childhood gingivitis group or the adult gingivitis group (p < 0.01). With both P. gingivalis and A. actinomycetemcomitans, positive correlations between elevated IgG level and infections by these microorganisms were found in the puberty gingivitis and adult periodontitis groups.