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

Effect of treatment on titer, function, and antigen recognition of serum antibodies to Actinobacillus actinomycetemcomitans in patients with rapidly progressive periodontitis

Although periodontal treatment by scaling and root planing (SCRP) is known to induce bacteremia, the effect of this procedure on the host immune response is not known. We have determined pre- and post-SCRP immunoglobulin G antibody titers to antigens of Actinobacillus actinomycetemcomitans in the sera of 22 patients with rapidly progressive periodontitis. We also assessed the ability of these sera to enhance phagocytosis and killing of A. actinomycetemcomitans by human polymorphonuclear leukocytes by using a polymorphonuclear leukocyte chemiluminescence (CL) assay. Specific anti-A. actinomycetemcomitans antibody titers were significantly increased at 6 and 12 months after beginning treatment, and CL values were significantly increased at 12 months, whereas mean interproximal pocket depths were significantly decreased at 12 months after beginning treatment. When patients were classified as either seropositive (twice the median titer of control subjects; n = 10) or seronegative (n = 12), both median titers and CL values were significantly increased for the seronegative group at 6 and 12 months after treatment. In the seropositive group, only the median titer was significantly increased at 12 months. Western blot (immunoblot) patterns for six seronegative and six seropositive patients differed remarkably at the baseline. Before treatment, all of the seropositive patients recognized high-molecular-mass lipopolysaccharide (LPS) and a large number of protein components. Patterns were virtually unaffected by therapy. Before treatment, only one of the seronegative patients recognized the LPS smear and none reacted strongly with protein components. Following treatment, slight LPS staining was observed for five of six seronegative patients and detection of protein bands was enhanced in all cases. We conclude that treatment by SCRP induces a humoral immune response, especially in seronegative patients, and that response may play a role in the observed beneficial effects of periodontal treatment.

Specificity and levels of oral and systemic antibodies to Actinobacillus actinomycetemcomitans

Salivary and gingival crevicular fluid antibodies and systemic antibodies were analysed for levels and specificity against Actinobacillus actinomycetemcomitans components. The major reactivity of salivary and serum IgA1 and IgA2 antibodies to the periodontal pathogen A. actinomycetemcomitans was against bands between 14 and 83 kD for IgA1 and bands between 14 and 68 kD for IgA2 in Western blot. In addition to specific binding, there was also a hitherto unrecognized Fc-mediated binding of IgG antibodies to an A. actinomycetemcomitans component around 50 kD. Serum IgG antibodies to A. actinomycetemcomitans leukotoxin displayed the highest median value and only 1 individual showed salivary IgM antibodies in ELISA. Elevated levels of gingival crevicular fluid IgA2 antibodies indicated a local production of IgA from periodontal tissues. Using synthetic peptides, several distinct epitopes on the leukotoxin were recognized by both salivary and serum IgA antibodies.

Transmission of Actinobacillus actinomycetemcomitans in families of adult periodontitis patients

At present Actinobacillus actinomycetemcomitans is regarded as an important microorganism in the etiology of some forms of periodontitis. The purpose of the present investigation was to study the number of Restriction Endonuclease Analysis (REA)-types present in the oral cavity of A. actinomycetemcomitans positive subjects and to study the possibility of transmission of A. actinomycetemcomitans within families of adult periodontitis patients. DNA of A. actinomycetemcomitans isolates was digested with a combination of the restriction endonucleases PstI and BamHI, after which the DNA fragments were separated by agarose gel-electrophoresis. To study the number of REA-types, multiple A. actinomycetemcomitans isolates obtained from 8 different sites in the oral cavity of five subjects were typed. The results showed that in most cases only one REA-type is present. In the 13 families investigated in 4 of the 26 children (15%) and in 1 of the 13 spouses (8%) of the adult periodontitis patients an indistinguishable REA-type was found within the families. This suggests that also in the case of adult periodontitis transmission of A. actinomycetemcomitans is possible, but does not seem to occur easily.

Reevaluation of the chromosome 4q candidate region for early onset periodontitis

Evidence of linkage (lod = 3.1, theta = 0.05) was reported previously in one large kindred (the Brandywine genetic isolate) for an autosomal dominant form of early onset periodontitis (EOP) with a protein polymorphism in the vitamin D binding protein (GC) located on chromosome 4q12-q13. To evaluate the generality of this finding, 19 unrelated families (228 individuals), each with two or more EOP affected individuals, were ascertained and sampled. A restriction fragment length polymorphism (RFLP) at the GC locus and eight other polymorphic DNA markers and two red blood cell antigens located on proximal chromosome 4q in the vicinity of the GC locus were typed. Twelve genetic models of EOP were evaluated, which varied in diagnostic classification, penetrance, and mode of disease transmission. Results for all models strongly exclude linkage between an EOP susceptibility gene and this chromosomal region assuming locus homogeneity. Our data statistically exclude (lod < or = -2.0) the possibility that more than 40% of our families are linked to this candidate region for one model tested. Linkage under heterogeneity was excluded less strongly for other models, but no significant evidence in support of linkage was obtained for any model. Our results indicate that either the previous report of linkage was a false positive, or that there are two or more unlinked forms of EOP, with the form located in 4q12-q13 being less common.

Immunoglobulin class and subclass distribution of antibodies reactive with the immunodominant antigen of Actinobacillus actinomycetemcomitans serotype b

The aims of this study were to determine the immunodominant antigens of Actinobacillus actinomycetemcomitans serotype b (Aab) for the different immunoglobulin (Ig) classes and subclasses and to determine the relative levels of these different Igs in serum. Seropositive early-onset periodontitis patients were sampled, and the Ig classes IgG, IgA, and IgM and subclasses IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2 were studied. Reactivity with Aab antigens was assessed by using the Western blot (immunoblot) in limiting dilution analysis and radioimmunoassay with sera from 13 early-onset periodontitis subjects. A smeared antigen in the upper portion of the immunoblots, typical of high-molecular-weight LPS, was immunodominant for IgG, IgA, IgM, IgG1, IgG2, IgG3, IgA1, and IgA2. This smeared antigen was present in every patient for all of these Igs at the endpoint. A few additional antigens were also present at the endpoint in some patients, but none were present in more than half of the subjects. The distribution of antibody titers by Ig classes reactive with the Aab immunodominant antigen was IgG > IgA > IgM. The distribution of antibody titers by IgG subclass was IgG2 > IgG1 approximately IgG3. Further quantitation by radioimmunoassay revealed that the mean concentration of IgG2 (65.7 micrograms/ml) was significantly greater than that of IgG1 (8.8 micrograms/ml). The IgA subclass distribution was IgA1 >> IgA2, with IgA1 apparently being second only to IgG2. Therefore, the Aab antigen eliciting the highest antibody level in virtually all Ig classes and subclasses appeared to be lipopolysaccharide, and IgG2 was markedly elevated over all other serum Ig classes or subclasses reactive with Aab.

Effects of treatment on antibody titer to Porphyromonas gingivalis in gingival crevicular fluid of patients with rapidly progressive periodontitis

Twenty-eight patients diagnosed as having rapidly progressive periodontitis (RPP) were enrolled in a study in which samples of subgingival microflora were harvested from test teeth and assayed for the presence of Porphyromonas gingivalis, and GCF collected and analyzed by ELISA for specific antibody for P. gingivalis. Clinical conditions were measured and recorded, and treatment by scaling and root planing provided at baseline and at 3, 6, 9, and 12 months. Reduction in pocket depth, stabilization of attachment level, and resolution of inflammation were comparable to previously reported values. By 3 months, mean and median specific antibody concentration had decreased, and continued to decrease through 12 months. The proportion of samples in which specific antibody was not detectable increased from 27% at baseline to 73% at month 12. GCF samples from sites at which P. gingivalis was present had greater than 2-fold higher median specific antibody than samples from P. gingivalis-negative sites. At baseline, specific antibody titer of 30-second GCF samples positively correlated with pocket depth, and GCF volume significantly correlated with antibody titer and concentration, and with pocket depth. In addition, change in specific antibody titer of 30-second samples from baseline to both 6 and 12 months correlated positively with pocket depths. Thus sites infected by P. gingivalis manifested high levels of specific antibody, and levels were related to clinical status. Following treatment, antibody levels decreased significantly as pocket depths decreased, attachment levels stabilized, and inflammation resolved.

Differential diagnosis in clinical trials of therapy for periodontitis

For purposes of clinical trials of therapies for periodontitis, it is recommended that population samples be identified as adult periodontitis (systemically modified or not systemically modified), early onset periodontitis (localized or juvenile, generalized or rapidly progressive, or associated with systemic disease), or necrotizing ulcerative periodontitis, avoiding overlapping criteria. Population samples of adult or early onset periodontitis modified by or associated with systemic conditions should be used in clinical trials only when the intent is to study effect on the specifically modified condition. Objective identification of the modifying systemic condition should be required for all subjects in such trials. Population samples should be homogeneous for the diagnosis, whether systemically modified or not. Refractory periodontitis, prepubertal periodontitis, and periodontitis associated with systemic disease are not recommended as useful descriptors of population samples without discrete identification of underlying systemic abnormality for all included subjects. Definition of population sample by a bacteriological or a host response feature is not recommended unless the trial is specifically aimed at that feature and the sample is homogeneous for it. All trials of efficacy should include physical or radiographic measurement of attachment level or bone height as a critical outcome variable. Results from trial in one form of periodontitis should not be applied directly to other forms.

Characterization of shared antigens of Fusobacterium nucleatum and Fusobacterium necrophorum

Fusobacterium nucleatum and Fusobacterium necrophorum are gram-negative, non-spore-forming anaerobic rods, frequently isolated from the normal flora and diseased lesions of the human oral cavity, gastrointestinal and genitourinary tracts. F. necrophorum is also known to be an animal pathogen. Studies were undertaken with rabbit anti-F. nucleatum sera and with human adult periodontitis (AP) sera that demonstrated the sharing of antigens between the two species. Immunodiffusion and immunoelectrophoresis studies of Fusobacterium species with rabbit anti-F. nucleatum sera demonstrated the presence of shared antigen(s) between F. nucleatum and F. necrophorum. Adsorption studies of AP sera in an enzyme-linked immunosorbent assay demonstrated the presence of antibodies reacting with the shared antigens of the two species. Immunoblot (IB) analysis of a soluble protein preparation of the two species of Fusobacterium, when allowed to react with rabbit anti-F. nucleatum 10197 serum, demonstrated 53 kDa and 30 kDa bands present in members of the two species. Further, IB analysis of protein preparations of the two species with AP sera indicated the presence of antibodies reacting with the shared 53 kDa band and in some cases the 30 kDa band. During serological testing with antisera or host immune studies with human sera to these species, the presence of shared antigens must be considered.

Serum immunoglobulin G antibody to Porphyromonas gingivalis in rapidly progressive periodontitis: titer, avidity, and subclass distribution

Porphyromonas gingivalis is a suspected pathogen in rapidly progressive periodontitis (RPP). We have determined the anti-P. gingivalis serum immunoglobulin G (IgG) isotype response and avidity and the subclass titer distributions for 30 RPP patients and 30 age-, sex-, and race-matched healthy subjects by using enzyme-linked immunosorbent assay technology. Patients and control subjects were classified as seropositive if their total IgG response to P. gingivalis was twofold or more than the median response in healthy subjects. The predominant antibody responses for both patients and healthy subjects were IgG2 and IgG3, with a subclass order of IgG2 greater than IgG3 greater than IgG1 greater than IgG4. The avidity of the IgG response was highest for the seropositive healthy subjects and was no different between seronegative and seropositive RPP patients. The subclass antibody responses did not depend on gender, and there were no correlations between titer, avidity, or subclass with disease severity in the RPP patients as measured by pocket depth or bone loss on dental X rays. The seronegative RPP patients exhibited antibody responses that were greater than the responses of seronegative healthy subjects for all four subclasses, while the seropositive RPP patients had higher IgG1 and IgG4 levels than seropositive healthy subjects. These findings are consistent with the hypothesis that both carbohydrate and protein antigens are important in the IgG response to P. gingivalis. The relative predominance of IgG2, a subclass which lacks strong complement fixation and opsonic properties, and the low avidity of patient anti-P. gingivalis IgG antibodies suggest that humoral responsiveness to infection with P. gingivalis may be ineffective in clearing this organism.

Immunoglobulin-degrading enzymes in localized juvenile periodontitis

Previous reports have indicated the association of periodontal diseases with elevated levels of serum immunoglobulin G (IgG) antibodies to periodontally relevant bacteria. Recent results from this laboratory suggest that enzymes proteolytic for immunoglobulins are important virulence factors of several periodontal bacteria. Specifically, enzymes from Porphyromonas (Bacteroides) gingivalis culture supernatant fluid (SF) cleaved human IgG (4 subclasses), IgA1 and IgA2, IgM, IgD and IgE. Proteolytic enzymes from Actinobacillus actinomycetemcomitans culture SF cleaved IgG, IgA and IgM. An enriched Ig proteolytic preparation from Capnocytophaga ochracea culture SF was shown to extensively cleave all 4 subclasses of human IgG. Extensive degradation of IgG and IgA in crevicular fluid samples on SDS-PAGE from periodontal disease sites of localized juvenile periodontitis (LJP) patients in comparison to little degradation in healthy sites indicated the potential role the proteolytic enzymes from periodontopathogenic bacteria may play in situ. Treatment of IgG with P. gingivalis, A. actinomycetemcomitans and C. ochracea SF resulted in similar patterns of degradation. LJP patients had significantly higher levels of IgG and IgA proteolytic activity in whole saliva than age-, sex-, and race-matched periodontal disease-free controls. However, not all of the proteolytic activity could be ascribed to bacterial proteases since neutrophils are also present in large numbers at diseased sites. Using similar techniques, lysates of neutrophils from healthy controls cleaved IgG, IgA and IgM. The observation of enhanced Ig cleavage activity in crevicular fluid and saliva in LJP patients suggest a role for Ig proteolytic enzymes in LJP.

Immunodominant antigens of Actinobacillus actinomycetemcomitans serotype b in early-onset periodontitis patients

Previous work with Actinobacillus actinomycetemcomitans strain Y4 (serotype b) indicates that the immunodominant antigen in high-responding patients (top 10%, 80% of which were black) is the serotype-specific antigen. In this study we examined the immunodominant antigens of A. actinomycetemcomitans strain Y4 in both black and white patients having a range of antibody titers. We sought to test the hypothesis that the immunodominant antigen in these subjects was the same antigen found in high responders. Seropositive white early-onset periodontitis (EOP) patients were selected from 99 EOP patients. Black subjects were then selected with comparable antibody titers. Double immunodiffusion and competition assays were used to determine whether reactive antibodies were A. actinomycetemcomitans serotype b-specific or whether the response was to serotype a or c. The immunodominant antigens were then determined for the patients reacting specifically to A. actinomycetemcomitans Y4 using limiting dilution analysis on Western blots. The immunodominant antigen for the A. actinomycetemcomitans Y4-specific patients appeared to be the serotype-specific carbohydrate for most subjects (19/20 or 95%, including: 13/14 black and 6/6 white patients). In conclusion, the immunodominant antigen for A. actinomycetemcomitans Y4 was the serotype-specific carbohydrate regardless of antibody titer for both black and white specifically reactive patients.

Phenotypic assessment of early onset periodontitis in sibships

Early onset periodontitis is a group of familial diseases that are not yet clearly defined by etiologic mechanisms, although some risk factors have been recognized. The disorders include a localized form of juvenile periodontitis (JP), and a more generalized form (GP). In a family study, 39 sibships (116 individuals, aged 13-48) were evaluated for clinical indices, neutrophil chemotaxis, and serum antibodies to A. actinomycetemcomitans (Aa). Of 77 siblings, 41 were healthy at examination. In 14 sibships, all affected persons had JP; 14 other sibships had all affected individuals with GP; and 11 had at least one sib with each form. For probands with decreased chemotaxis, 71% of affected sibs and 36% of clinically healthy sibs had decreased chemotaxis. For Aa seropositive probands, 83% of affected siblings and 65% of currently healthy sibs were also seropositive. The associations of disease with these risk factors were stronger in JP-only sibships. Some affected sibs had neither risk factor, while many currently healthy sibs had 1 or both. While these 2 factors demonstrate population association with disease, neither fits the pattern expected within families to clearly suggest a causal mechanism. The assessment of within and among family variability remains the best approach for recognition of possible causal mechanisms and sources of heterogeneity.

Serum IgG reactive with oral anaerobic microorganisms associated with infections of endodontic origin

Numerous species of bacteria have been implicated with infections of endodontic origin. The purpose of this study was to compare the levels of serum IgG antibodies reactive with a panel of 10 oral anaerobic microorganisms implicated in infections of endodontic origin. Serum samples were collected from 4 patient groups that included healthy patients without endodontic or periodontal disease, patients with chronic adult periodontal disease, patients with endodontic disease and patients with combined endodontic-periodontal disease. When Prevotella intermedia was allowed to react with sera from the 4 patient groups, significant pairwise differences were shown between the healthy group and each of the other 3 groups. In addition, there was a significant difference between the periodontal disease group and the combined endodontic-periodontal disease group. When Porphyromonas gingivalis was allowed to react with sera from the 4 patient groups, significant pairwise differences were shown between the healthy group and the periodontal disease group, the healthy group and the combined endodontic-periodontal disease group, the endodontic disease group and the periodontal disease group and the endodontic disease group and the combined endodontic-periodontal disease group. The results of this investigation support other studies that associate P. intermedia with both endodontic disease and chronic adult periodontal disease. The results also support studies that implicate P. gingivalis as a periodontopathogen.

Humoral immune responses to Porphyromonas gingivalis before and following therapy in rapidly progressive periodontitis patients

We have performed studies aimed at elucidating the nature of the humoral immune response in rapidly progressive periodontitis (RPP). We analyzed the sera of 36 periodontally normal subjects and 36 RPP patients for titers and avidities of IgG antibodies reactive with the antigens of Porphyromonas gingivalis using ELISA, prior to and following treatment. We used whole-cell sonicate, purified lipopolysaccharide (LPS), and total extractable protein as plate antigens. Twelve of the patients had antibody titers at least 2-fold greater than the median of the controls and were designated as seropositive. The remaining 24 patients had titers that did not exceed twice the median titer of the controls and were designated as seronegative. For both patient groups, antibody titers were highest when whole-cell antigen was used, intermediate for LPS, and lowest for the protein fraction. Following treatment, median titer for seropositive patients decreased from pretreatment values of 241.7 to 76.5, while median titer for seronegative patients increased from 39.5 to 80.1. Avidities of pretreatment sera from both patient groups for all 3 antigen preparations were lower than the median avidities of the control sera. Avidity significantly increased following treatment to levels greater than those for control sera in both patient groups. Thus, some young adults with severe periodontitis mount a humoral immune response and produce high levels of serum IgG antibodies reactive with antigens of P. gingivalis, while others do not. The antibodies produced are of relatively low avidity, and may therefore be relatively ineffective biologically. Therapy, which greatly reduces antigen load, appears to stimulate production of higher avidity IgG antibodies in both patient groups; in the seropositive group, low avidity antibodies appear to be replaced by antibodies of higher avidity. Both the purified LPS and protein fractions contain reactive antigen(s), although LPS binds more antibody. Our data are consistent with the idea that many RPP patients do not produce protective levels of biologically functional antibody during the course of their natural infection, but they may be stimulated to do so by treatment.

Diagnosis of periodontal diseases

This paper reviews current (Fall, 1990) information related to the diagnosis of periodontal diseases. As background, principles of diagnostic decision-making and conceptual shifts during the 1970's and 1980's are reviewed in brief. "Diseases" that appeared in many classification schemes for periodontal diseases in the early 1970's--for example, "periodontosis" and "occlusal trauma"--do not appear in most current classifications. A recent (1989a) classification recommended by the American Academy of Periodontology holds that "periodontitis" includes several different diseases. There is, indeed, evidence for several different forms of periodontitis, but the AAP's classification does not conform to the principles of diagnostic decision-making because of the significant overlap between and heterogeneities within its suggested "diseases". An alternative classification is suggested, based on a concept that the periodontal diseases are mixed infections whose outcome is modified by relative effectiveness of host response. This view suggests that the most usual forms, gingivitis and adult periodontitis, normally occur in persons with essentially normal defense systems. Variation in extent or severity of disease can be understood as a function of the local infection in hosts with various degrees of compromised resistance to the infection. Early-onset periodontitis (EOP) cases could be accounted for by those where host response is abnormal to some significant degree. The greater the abnormality, the greater the extent and severity of disease might be. Localized EOP cases would be those where a relatively effective specific response intervenes to ameliorate progress of disease after the initially rapid progression. Other issues are detection of disease activity and assessment of risk for disease progression. Non-cultural bacteriological tests are available, but have not yet been shown to detect or predict activity or risk. One difficulty in reaching such proof for those or other tests has been the lack of an appropriate "gold standard" for disease activity or progression. This is being remedied by development of improved automated probes and imaging technologies. Considerable effort is being devoted to determining whether factors in gingival crevicular fluid may have diagnostic utility. More evidence is needed before clinical utility is known, but several enzymes and cytokines have potential for aiding diagnostic decisions.

The immunodominant outer membrane antigen of Actinobacillus actinomycetemcomitans is located in the serotype-specific high-molecular-mass carbohydrate moiety of lipopolysaccharide

Most patients with juvenile periodontitis manifest serum antibodies, sometimes at very high titers, to antigens of Actinobacillus actinomycetemcomitans, but the antigens inducing the immune response have been only partly characterized. We separated A. actinomycetemcomitans serotype b cells into protein, lipopolysaccharide (LPS), and soluble polysaccharide fractions and characterized them. Coomassie blue- and silver-stained sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels were used to detect protein and LPS components, and gas-liquid chromatography was used to determine their carbohydrate and fatty acid composition. Western blots, dot blots, and enzyme-linked immunosorbent assay inhibition with high-titer sera from juvenile periodontitis patients revealed which components were highest in antibody binding activity. These results showed that the major portion of the immunoglobulin G binding activity resides in the purified mannan-free LPS, with lesser amounts in the total protein fraction. Using Sephacryl S-300 chromatography, we separated LPS into high-molecular-mass components with high carbohydrate contents by gas-liquid chromatography and a low-molecular-mass component consisting mainly of lipid A and the inner core sugar heptulose. The results of quantitative dot blot assays and enzyme-linked immunosorbent assay inhibition show that the serotype-specific antibody binding activity is highly concentrated in the high-molecular-mass carbohydrate-rich LPS fraction and is almost completely absent in the low-molecular-weight lipid-rich fraction. Our observations contrast with previous reports that the predominant serotype antigen of A. actinomycetemcomitans resides in a mannan-rich polysaccharide isolated from spent culture medium. These observations support the conclusion that the immunodominant antigen of the outer membrane is the O antigen of the LPS.

Immunodominant antigens of Actinobacillus actinomycetemcomitans serotypes a and c in high-responder patients

This study was undertaken to examine the characteristics of the immunodominant antigens of Actinobacillus actinomycetemcomitans serotypes a and c. The top responders for A. actinomycetemcomitans serotypes a and c were selected (19 for serotype a and 21 for serotype c) from 150 clinically characterized patients. Competition assays revealed that 9 of 19 of these patients were reacting specifically to serotype a and 12 of 21 for serotype c. Limiting dilution analysis on Western blots revealed that most antigen bands apparent at low dilution disappeared as the patient's serum was diluted. The antigen band(s) remaining at the endpoint or the dilution corresponding to the antibody titer were defined as immunodominant. For serotype a there were several different immunodominant antigens but none was present in more than half of the subjects. For serotype c the immunodominant antigens included a number of discrete bands and a diffuse smeared polysaccharide band. Only 2 of these antigens were present in the majority of the high-responders: 92% had the smeared antigen and 67% had a 15 kDa antigen. The 15 kDa band was a protein common to all A. actinomycetemcomitans serotypes. The smeared antigen was unaffected by protease K treatment and gave a reaction of identity with the serotype c specific rabbit antiserum. This rabbit antiserum is specific for a mannan carbohydrate and does not react with LPS (23). Therefore, the smeared immunodominant antigen appears to be a polysaccharide containing mannan.

Immunologic mechanisms of pathogenesis in periodontal diseases: an assessment

Principal lines of evidence that immune reactions are central to the pathogenesis of periodontitis are reviewed. Necessary components of immunologic reactions are present in gingiva in the periodontal diseases. Differences between healthy and periodontitis patients with respect to some measures of immune function further indicate that immune reactions do occur in the gingiva during periodontitis. They are probably responsible for at least some of the destruction of connective tissue and bone that occurs. Classical antibody-mediated hypersensitivity reactions probably do not provide the reasons. Mechanisms are more likely to be found in the pro-inflammatory and tissue-degrading effects of cytokines released in host-protective, antigen-specific and polyclonal responses to oral bacterial constituents or products. Some evidence suggests that limitation of clinical destruction in localized early onset periodontitis (JP) may in part be a function of a protective antibody response which develops after an initial rapidly progressive infection. A relatively deficient immune responsiveness may allow progression to more severe and generalized disease (RPP). Suggestions are made for studies needed to confirm suspected pathogenetic mechanisms, approach resultant targeted therapies, and test hypotheses for contrasting roles of immune reactions in different clinical expressions of periodontitis.

Measurement of relative avidity of antibodies reactive with Porphyromonas (Bacteroides) gingivalis in the sera of subjects having adult periodontitis

Relative avidities of antibodies to Porphyromonas (Bacteroides) gingivalis in the sera of 15 patients having adult periodontitis and 15 healthy subjects were evaluated using an ammonium thiocyanate-dissociated ELISA. Graded concentrations of ammonium thiocyanate were added to a single dilution of serum in order to dissociate low avidity antibody binding to P. gingivalis. The concentration of thiocyanate resulting in 50% reduction in binding (absorbance) was termed the ID50 for that serum. When IgG-class antibodies were examined, the ID50 of anti-P. gingivalis antibodies in the sera of patients was significantly elevated (0.96M vs 0.71M; p less than 0.01, Student's t-test). In contrast, when IgM-class antibodies were examined no significant differences in ID50 between patients and controls were found for P. gingivalis (0.54M vs 0.53M). While the ID50 values of patient antibodies were found to be elevated relative to those of healthy controls, comparison with antibodies from rabbits immunized with P. gingivalis and with ID50 values from other human studies suggests that adult humans, in general, produce very low-avidity antibodies to P. gingivalis. It is suggested that the presence of low-avidity antibodies contributes to the pathology associated with periodontal disease.

Antigens of Actinobacillus actinomycetemcomitans recognized by patients with juvenile periodontitis and periodontally normal subjects

Most juvenile periodontitis patients respond to infection by Actinobacillus actinomycetemcomitans by producing serum antibodies. Specific antigens inducing the humoral immune response have not been identified, nor has the role of the resulting antibodies in disease progression been determined. Adsorbed and unadsorbed sera from juvenile periodontitis patients and normal subjects were analyzed by enzyme-linked immunosorbent assay and Western blots (immunoblots), using digested and undigested bacterial sonicates and French pressure cell fractions to determine the biochemical class, cross-reactivity, and cellular location of the antigens in different A. actinomycetemcomitans serotypes. Antigens detected by using high-titer sera included the following: (i) serotype-specific nonprotein material located on the cell surface, (ii) soluble-fraction proteins showing highly variable antibody binding, (iii) cross-reactive proteins, and (iv) a protein present in soluble and cell wall fractions and immunopositive for all sera tested. In addition, one apparently nonprotein component that was enriched in the cell wall fraction was observed. Sera with high immunoglobulin G titers to one, two, three, or none of the three A. actinomycetemcomitans serotypes were observed. There was a high degree of variation from one patient to another in the humoral immune response to serotype-specific and cross-reactive antigens. As demonstrated by whole-cell adsorption experiments, the serotype-specific surface antigen accounted for approximately 72 to 90% of the total antibody-binding activity for sera with titers greater than 100-fold above background, while cross-reactive antigen accounted for less than 28%. Antibody binding the whole-cell sonicate for high-titer sera was inhibited 90% by lipopolysaccharide from the same serotype, strongly suggesting that lipopolysaccharide is the immunodominant antigen class.

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.

Bacteroides gingivalis-specific serum IgG and IgA subclass antibodies in periodontal diseases

The level of serum IgM, IgG and IgA antibodies including IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2 subclass-specific antibodies to Bacteroides (Porphyromonas) gingivalis fimbriae and to lipopolysaccharide (LPS) were analysed in patients with different forms of periodontal disease (PD) and control subjects by ELISA. Among PD subjects, sera obtained from adult periodontitis (AP), rapidly progressive periodontitis (RPP) and gingivitis contained high titres of fimbriae-specific IgG antibodies (7500-15,000 ELISA units) followed by IgA (90-700 units) and IgM (30-90 units). In contrast, sera from localized juvenile periodontitis (LJP) subjects exhibited much lower titres of fimbriae-specific IgG (89 +/- 11 units), IgA (31 +/- 5 units) and IgM (17 +/- 3 units) antibodies. A similar response pattern was also seen in sera from normal subjects aged 35-41 years who practice normal oral hygiene, while sera of younger adults (aged 18-24) with superior hygiene did not have any antigen-specific antibodies. Analysis of IgG subclass anti-fimbriae responses revealed that the major response was IgG3 followed by IgG1, IgG2 and IgG4 in AP, RPP and gingivitis. Although lower, a similar pattern of IgG subclass titre was seen in LJP and normal subjects aged 35-41 years. When IgA subclass responses were measured in AP and RPP, higher titres of the fimbriae-specific response were noted with IgA1 when compared with IgA2. However, lower but approximately equal levels of fimbriae-specific IgA1 and IgA2 titres were seen in other PD groups. When anti-B. gingivalis LPS-specific responses were measured, the sera of AP patients contained high levels of IgG antibodies (2265 +/- 224 units) followed by IgA (411 +/- 90 units) and IgM (214 +/- 56 units). Further, IgG anti-LPS responses were mainly IgG2 followed by IgG4, IgG3 and IgG1. For IgA subclass responses, higher titres of anti-LPS-specific antibodies were noted in IgA2 subclass over IgA1. These results showed that higher anti-B. gingivalis antibody responses occur in PD when compared with healthy individuals and protein and lipid-carbohydrate antigens of B. gingivalis induce distinct patterns of antigen-specific IgG and IgA subclass responses.

Actinobacillus actinomycetemcomitans in families afflicted with periodontitis

The purpose of this study was to determine the prevalence of Actinobacillus actinomycetemcomitans (Aa) in individuals from families where at least one individual has an early onset form of periodontitis. Twenty-three families with 73 subjects were evaluated in this study. Forty-seven early onset periodontitis subjects outside the 23 families were also studied. Prevalence of detection of Aa in family members ranged from 49% to 66% among groups constituted by clinical findings indicative of no loss of attachment, adult periodontitis, generalized severe juvenile periodontitis, or localized juvenile periodontitis. Whether the data were analyzed by subject or by site, no statistical differences could be found in prevalence (proportion of positive samples) among those clinical groups. The only significant difference was that localized juvenile periodontitis subjects had higher concentrations of Aa in their Aa-positive sites than did the other clinical groups. The prevalence of Aa-positive sites in subjects without attachment loss, but who are members of families in which early onset periodontitis is represented, was much higher than in other reports where periodontally healthy subjects were not related to early onset periodontitis cases. This suggests that Aa may be transmitted among members of families in which one or more members has an early onset form of periodontitis.

Serum antibodies to periodontal bacteria

The purpose of this study was to determine how serum antibodies reactive with periodontitis-associated bacteria with relates to the diagnosis of periodontitis subjects. Study groups included localized juvenile periodontitis (LJP) subjects, severe periodontitis (SP) subjects, chronic adult periodontitis (AP) subjects, and age matched controls. Twenty-two bacterial strains, representing 18 different species most commonly found in early onset periodontitis were evaluated using serum from LJP, SP, and age matched controls. Serum IgG reactive with these organisms was determined using a radioimmunoassay (RIA). Serum antibody reactive with 13 bacterial strains differed significantly (P less than 0.01) between the three clinical groups. Discriminate analysis revealed that antibodies reactive with 5 bacterial strains of the 13 were able to identify the clinical group to which subjects belonged 79% of the time with control subjects being correctly identified 100% of the time, LJP subjects 78% of the time, and SP subjects 60% of the time. These strains included two strains of Actinobacillus actinomycetemcomitans (Y4 and N27), Fusobacterium nucleatum (E1D1), Eubacterium brachy, and Bacteroides gingivalis. The low classification rate of SP subjects suggested heterogeneity. The SP group could be divided into three subgroups using the serological data. One subgroup, with "super" severe attachment loss, generally lacked antibody reactive with these five organisms, another subgroup was serologically similar to LJP subjects, while the third subgroup had antibodies to additional organisms. This suggests that some SP subjects may represent a more advanced form of LJP. Comparison of antibody reactivity of AP subjects with age matched controls to 23 bacterial types revealed that mean serum antibody reactivity to only Bacteroides gingivalis was higher in AP subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Juvenile and rapidly progressive periodontitis. Peripheral blood lymphocyte subpopulations

Juvenile and rapidly progressive periodontitis are grouped under the heading of early-onset periodontitis. In recent years, much attention has been devoted to studying immunologic factors in early-onset periodontitis. This study was designed to investigate peripheral blood lymphocyte subpopulations, natural killer cells and interleukin-2 receptor positive (IL-2R +) cells in patients with juvenile and rapidly progressive periodontitis. 38 patients with juvenile and 30 patients with rapidly progressive periodontitis, plus 30 normal healthy control subjects were included in the study. Peripheral blood T-lymphocytes, helper T-cells, suppressor T-cells, HLA-DR+ cells, and IL-2R + cells were determined using appropriate monoclonal antibodies and the indirect immunofluorescence method. B-lymphocytes were identified using the direct immunofluorescence technique. Both groups of patients had normal number of total CD3+ T-cells, CD4+ helper T-cells, CD8+ suppressor T-cells, HLA-DR+ cells and IL-2R+ cells. Natural killer cells were found to be significantly elevated in both groups. These findings could contribute to the immunopathogenesis of early-onset periodontitis.

Prepubertal periodontitis: a review of diagnostic criteria, pathogenesis, and differential diagnosis

This paper reviews the literature on prepubertal periodontitis (PP) according to the definition and the classification of PP by Page. The generalized form of PP (G-PP) defined by Page was identified as the oral manifestation of a systemic disease called leukocyte adhesion deficiency (LAD) and thus the pathogenesis is known at the molecular level. On the other hand, the localized form of PP (L-PP) is a disease defined by clinical criteria and its pathogenesis is not known at the molecular level. The reported prevalence of L-PP differs widely in reports, according to the methodology and population studied. However, it seems to be at least 0.84% or greater. Potential periodontal pathogens that have been associated with L-PP include the following bacteria: Actinobacillus actinomycetemcomitans (A.a.), Bacteroides intermedius, Bacteroides gingivalis, Capnocytophaga sputigena, and Eikenella corrodens. Suggested contributing factors have included PMN or monocyte chemotactic defects and cementum defects. There is no unique pattern of bone loss in L-PP; however, there may be a type of periodontitis that affects all deciduous teeth, in the absence of LAD. L-PP may lead to localized juvenile periodontitis (LJP) or generalized juvenile periodontitis (GJP). Histiocytosis X, hypophosphatasia and mild forms of blood dyscrasias may have minimal or no clinical signs and symptoms except for alveolar bone loss. Therefore diseases known to be associated with alveolar bone loss must be definitively excluded in prepubertal children until the pathogenesis of L-PP at the cellular and molecular levels is understood and L-PP can be definitively diagnosed either as a distinct disease entity or entities.

Humoral immune responses in experimental gingivitis in rats

Serum IgG, IgM, and IgA antibody levels to extracts of rat dental plaque and five oral bacteria (Haemophilus actinomycetemcomitans Y-4, Bacteroides gingivalis 381, Bact. intermedius ATCC 25261, Capnocytophaga sp. M-12, Eikenella corrodens ODU) were determined by ELISA. In addition, the presence of rat dental plaque and oral bacterial components in the inflamed gingival tissue was studied using immunofluorescence techniques. Serum and gingival tissue samples were obtained from ODU plaque-susceptible and plaque-resistant rats. In several susceptible rats, IgG, IgM, and IgA antibodies against dental plaque and oral bacteria were detected. There was a correlation between the levels of IgG antibody to dental plaque and pocket probing depth, but not between pocket probing depth and the levels of IgM and IgA. Furthermore, components of rat dental plaque and oral bacteria were detected in the inflamed gingival tissue.

Clinical and laboratory characterization of early onset periodontitis

Clinical and laboratory data were compared in 72 patients with localized periodontitis (LP) and 103 patients with generalized periodontitis (GP). Significantly more LP than GP cases had decreased neutrophil chemotaxis (CTX), and were seropositive for Actinobacillus actinomycetemcomitans (Aa). Significantly, more GP cases were seropositive for Bacteroides gingivalis (Bg). All clinical indices were similar on affected teeth in LP and GP, but the attachment loss was greater on clinically unaffected teeth in GP when compared with LP. LP cases with CTX defects had a significantly lower mean age, were more often seropositive for Aa antibodies, and were more often female than LP patients with normal CTX. Significantly more GP cases with CTX defects were seropositive for Aa antibody. GP patients with normal CTX had a higher plaque index on both affected and unaffected teeth than did GP patients with a CTX defect. Our data suggest that chemotaxis and/or specific bacteria may be contributory, but not always necessary, factors in these disorders. The overlap in clinical and laboratory profiles of LP and GP continues to cloud the distinction of these early onset forms of periodontitis.

Cell surface protein antigen from Wolinella recta ATCC 33238T

A high-molecular-weight (approximately 150,000) protein was selectively isolated by acid extraction from the cell surface of Wolinella recta and purified by negative adsorption on DEAE-cellulose and gel filtration. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that this protein was found in W. recta but not in other Wolinella species, such as W. curva and W. succinogenes. Sera from patients with periodontitis reacted strongly with this protein antigen, whereas sera from healthy donors showed little or no reactivity, as determined by immunoblotting analysis. In serum, titers of immunoglobulin G antibodies to the protein antigen were significantly higher in patients with periodontitis than in periodontally healthy donors, as detected by an enzyme-linked immunosorbent assay.

Immunodominant antigen of Actinobacillus actinomycetemcomitans Y4 in high-responder patients

This study was undertaken to look for characteristics of the immunodominant antigen(s) of Actinobacillus actinomycetemcomitans Y4 that might help explain the high antibody titers in periodontitis patients. Radioimmunoassays (RIA) were performed on sera from 481 patients; sera from the 32 patients with the highest anti-Y4 titers (above 128,000 RIA U/ml) were further analyzed. Y4 antigen was boiled for 45 min or treated with papain, and antibody responses were analyzed by RIA and Western blotting (immunoblotting). In addition, carbohydrate was purified from Y4 and examined by Western blotting. The results indicated that the immunodominant antigen of Y4 in high responders was stable after papain treatment or boiling for 45 min. Papain or boiling eliminated protein bands but a large diffuse band persisted on Western blots. With increasing dilutions of sera, bands on Western blots corresponding to protein antigens disappeared, while the large diffuse band resembling that of carbohydrate persisted. Partially purified Y4 carbohydrate contained the large diffuse band. Double-immunodiffusion analysis indicated that rabbit serotype b-specific antiserum and patient sera recognized the same antigen. When the carbohydrate extract was passed over a lipid A-binding column to remove lipopolysaccharide, the smear corresponding to the immunodominant antigen was still present on Western blots. The immunodominant antigen of Y4 in high-responder individuals appears to be a carbohydrate and is possibly the capsular polysaccharide.

Serum immunoglobulin G antibody to periodontal bacteria

The purpose of this study was to assess the serum antibody levels to periodontal bacteria in patients with periodontal disease, and to explore the diagnostic uses of the serum antibody assessment and its potential as a therapeutic guide.

One hundred twenty-nine patients were clinically examined for the type and extent of periodontal destruction and serum IgG antibody levels to Actinobacillus actinomycetemcomitans (Aa), Actinomyces israelii (Ai), A. viscosus (Av), Bacteroides asaccharolyticus (Ba), B. corporis (Bc), B. denticola (Bd), B. gingivalis (Bg), B. intermedius (Bi), B. loescheii (BI), Capnocytophaga gingivalis (Cg), C. ochracea (Co), and Fusobacterium nucleatum (Fn). Clinical and serological data were subjected to correlation analyses. A small group of patients was monitored during the progress of periodontal treatments.

The IgG antibody levels were assessed with an enzyme-linked immunosorbent assay (ELISA).

Significantly elevated IgG antibody levels were manifested to Aa, Ai, Bg, and Fn in all forms of periodontal disease, additionally to Cg and Co in juvenile periodontitis, and to Bi in adult periodontitis. There were some correlations between a few clinical parameters and the antibody levels. Successful periodontal treatment significantly decreased the antibody levels to all of the micro-organisms; however, during periodontal treatment, there were no marked differences between pre- and post-treatment levels.

The antibody reactivities to the periodontopathic micro-organisms may be of diagnostic and predictive value in patients.

Problems of genetic model testing in early onset periodontitis

Familial aggregation of early onset or juvenile periodontitis (JP), a disorder that varies in expression and age of onset, has been recognized for some time. Autosomal recessive and X-linked inheritance patterns have been suggested, and one large pedigree has demonstrated autosomal dominant inheritance. The variability and age limitations in clinical phenotypic diagnosis present several problems to genetic analysis, because information on members of the youngest and older generations may be lost to the analysis. The purpose of the present study was to elucidate the genetic basis of JP by formal pedigree analysis and comparison of competing genetic models. Twenty-eight families were included, with general and specific autosomal models, and an X-linked model being compared. The autosomal recessive model provided the most parsimonious explanation of the data, and its likelihood was not significantly different from the more general model. Likelihoods for the sporadic (nongenetic) and X-linked models were considerably lower than the autosomal models. While comparison of genetic models suggests recessive inheritance of JP, the serious complications to pedigree analysis posed by limitations warns against acceptance of this conclusion, without more exhaustive evaluation of: (1) a more extensive collection of family data, (2) more complete investigation of the effects of age limitations on comparisons among competing models, and (3) elucidation of the importance of diagnosis and phenotype assignment of adults through past dental records.

Bacteroides gingivalis, Bacteroides intermedius and Actinobacillus actinomycetemcomitans in human periodontal diseases

Bacteroides gingivalis, Bacteroides intermedius and Actinobacillus actinomycetemcomitans seem to be major pathogens in advancing periodontitis in man. First, these organisms are recovered in higher prevalence and proportions from progressive periodontitis lesions than from quiescent periodontal sites. Second, antibody levels against B. gingivalis and A. actinomycetemcomitans are markedly elevated in serum and gingival crevice fluid of periodontitis patients compared to normal controls. Third, B. gingivalis and B. intermedius elaborate potent proteases and A. actinomycetemcomitans various noxious substances which have the potential to perturb important host defenses and to disintegrate key constituents of the periodontal tissues. Monitoring these bacteria in advanced periodontal lesions may greatly assist the assessment of treatment efficacy and risk of further periodontal breakdown.

Effect of periodontal therapy on specific antibody responses to suspected periodontopathogens

The effects of clinically successful periodontal therapy were studied in juvenile periodontitis (JP) and rapidly progressive periodontitis (RP) patients and compared with periodontally healthy subjects (HS). Serum samples were obtained in 35 HS prior to the study and in 12 of these subjects 3-4 years later. Serum samples were obtained from 50 JP patients initially, 9 subjects immediately following surgical therapy and 29 of these subjects 3-4 years later. RP patients provided 46 initial serum samples, 9 following therapy and 27 samples 3-4 years later. Antibody levels were determined utilizing a standardized enzyme-linked immunosorbent assay with Bacteroides gingivalis, B. ochracea, Fusobacterium nucleatum and Actinobacillus actinomycetemcomitans serving as antigens. The JP patients showed an initial rise in antibody levels immediately following therapy followed by a significant decrease in antibody levels 3 to 4 years later. The RP patients did not show an early change in antibody levels but by 3 to 4 years post-therapy, antibody levels had significantly decreased. However, during this study, the antibody levels of JP and RP patients remained significantly higher when compared with HS patients.

Systemic antibody response of clinically characterized patients with antigens of Eubacterium brachy initially and following periodontal therapy

Eubacterium brachy, a gram-positive anaerobic rod, has been implicated by cultural studies to be associated with the microflora of periodontal diseases. Serum samples from 184 clinically characterized patients were evaluated in a standardized enzyme-linked immunosorbent assay (ELISA) for reactivity to E. brachy antigens. Sera from clinically healthy subjects (HS) served as controls. Sera from rapidly progressive periodontitis (RP) patients demonstrated significantly greater reactivity by ELISA than did HS when reactivity with E. brachy antigens was determined (P less than 0.05). Juvenile periodontitis (JP) and adult periodontitis (AP) patients did not differ in reactivity by ELISA from HS (P greater than 0.05). Three to 4 years following successful periodontal therapy, reactivity was not significantly altered in any patient group (P greater than 0.05). The possible significance of these findings and the importance of an extracellular antigen of E. brachy in the immunopathology of periodontal diseases are discussed.