The effect of periodontal therapy on lymphocyte blastogenesis to plaque associated microorganisms

Comparison of the benzoyl-DL-arginine-naphthylamide (BANA) test, DNA probes, and immunological reagents for ability to detect anaerobic periodontal infections due to Porphyromonas gingivalis, Treponema denticola, and Bacteroides forsythus

Most forms of periodontal disease are associated with the presence or overgrowth of anaerobic species that could include Treponema denticola, Porphyromonas gingivalis, and Bacteroides forsythus among others. These three organisms are among the few cultivable plaque species that can hydrolyze the synthetic trypsin substrate benzoyl-DL-arginine-naphthylamide (BANA). In turn, BANA hydrolysis by the plaque can be associated with periodontal morbidity and with the presence of these three BANA-positive organisms in the plaque. In this investigation, the results of the BANA test, which simultaneously detects one or more of these organisms, were compared with the detection of these organisms by (i) highly specific antibodies to P. gingivalis, T. denticola, and B. forsythus; (ii) whole genomic DNA probes to P. gingivalis and T. denticola; and (iii) culturing or microscopic procedures. The BANA test, the DNA probes, and an enzyme-linked immunosorbent assay or an indirect immunofluorescence assay procedure exhibited high sensitivities, i.e., 90 ot 96%, and high accuracies, i.e., 83 to 92%, in their ability to detect combinations of these organisms in over 200 subgingival plaque samples taken from the most periodontally diseased sites in 67 patients. This indicated that if P. gingivalis, T. denticola, and B. forsythus are appropriate marker organisms for an anaerobic periodontal infection, then the three detection methods are equally accurate in their ability to diagnose this infection. The same statement could not be made for the culturing approach, where accuracies of 50 to 62% were observed.

Comparison of various detection methods for periodontopathic bacteria: can culture be considered the primary reference standard?

The development of diagnostic tests for a periodontal infection raises the issue as to what the appropriate reference standard, or "gold standard," should be for the evaluation of a new test. The present research was initiated to compare the ability of several detection methods, i.e., a serial dilution anaerobic culture and/or microscopic procedure, a DNA probe procedure, and immunological reagents using both an enzyme-linked immunosorbent assay and an indirect immunofluorescence assay to detect Treponema denticola, Porphyromonas gingivalis, Bacteroides forsythus, and Actinobacillus actinomycetemcomitans in subgingival plaque samples taken from 204 periodontally diseased tooth sites. The prevalence of the four monitored species varied as a function of both the species and the detection method. Spirochetes were present in 99% of the plaques, whereas A. actinomycetemcomitans was detected at the lowest frequency. The culture method yielded the lowest prevalence values for the three cultivable species. This raised the question as to which results, those obtained by culture or those obtained by the DNA probes and the immunological reagents, were the most reliable. This issue was addressed by looking at the prevalence profile of the monitored organisms, as determined by all the detection methods. If the species was detected by three or four of the detection methods, then it was considered present, whereas if it was absent by three or four of the detection methods, then it was considered absent. This approach showed the DNA probes and immunological reagents to be significantly superior (P less than 0.05) to the culture approach for the detection of P. gingivalis, A. actinomycetemcomitans, and B. forsythus and to be comparable to the microscopic approach in the detection of T. denticola.

Effect of initial treatment of chronic inflammatory periodontal disease on the frequency of peripheral blood T-lymphocytes specific to periodontopathic bacteria

Limit dilution analysis (LDA) was used to determine the effect of initial treatment of chronic inflammatory periodontal disease on the frequency of periodontopathic bacteria-specific T-cells in peripheral blood. Eleven marginal gingivitis (MG) and 8 adult periodontitis (AP) subjects took part in the study. The proliferative T-lymphocyte precursor (PTL-P) frequencies to Porphyromonas gingivalis and Actinomyces viscosus were determined using LDA and Poisson statistics both before and after treatment. Tetanus toxoid was used as a control antigen. Treatment resulted in a significant reduction in clinical disease parameters in both groups. The median peak PTL-P frequency for P. gingivalis was significantly higher in the AP group compared with the MG group before treatment. This was not the case after treatment nor with A. viscosus. In the MG group the median peak PTL-P frequency with both P. gingivalis and A. viscosus declined as a result of treatment. Although this decline was not statistically significant it may indicate an antigen-specific response in this group. In the AP group the median peak PTL-P frequency with P. gingivalis before treatment was 83.76 x 10(-6) (approximately 1 in 12,000) and after treatment it was 36.17 x 10(-6) (approximately 1 in 28,000). Dose-response relationships showed at each concentration of organisms/well this trend for a decline in PTL-P frequency after treatment, suggesting that any increased responsiveness to this organism in this group may be largely antigen-specific. However, there was no difference in this group in the median peak PTL-P frequency with A. viscosus before and after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Polyclonal B-cell activation in periodontitis

The evidence that periodontitis-associated bacteria contain potent PBA factors is very strong. Clearly, antibodies directed against non-oral antigens are produced in the inflamed periodontal lesion, and PBA appears to contribute to that production. It is also clear that B cells and plasma cells are the major cell types in the periodontal lesion. Furthermore, alterations in the regulation of B-cell responses to PBA factors are associated with severe periodontal disease. However, evidence demonstrating that activated B cells and plasma cells are directly involved in the pathogenic mechanisms leading to destruction of the periodontal support is still circumstantial. Polyclonal B-cell activation and potential pathways by which PBA-stimulated cells could be involved in periodontal destruction remain largely hypothetical. It appears that IL-1 is an important osteoclast-activating agent, and that LPS, which is a potent PBA factor in many systems, can elicit IL-1 production by B cells as well as by the monocyte/macrophage lineage. Recent data indicating that IL-1 is produced by numerous malignant B-cell lines lend support for the idea that B-cell IL-1 could be important in bone resorption. It is also likely that polyclonal activation may lead to production of autoantibody such as anti-type I and anti-type III collagens, and the destruction of self tissues through ADCC reactions, immune complex formation, and complement activation. Further research is needed to determine how the B cell/plasma cell may participate in tissue injury in periodontitis, and how the B-cell response to PBA factors is regulated.

Humoral immune response to selected subgingival plaque microorganisms in insulin-dependent diabetic children

Juvenile diabetics have been shown to have an increased susceptibility to gingivitis and periodontitis following puberty. However, little data are available on changes in the microbial flora that occur at the onset of puberty. This study was performed to determine if antibacterial antibody titers to selected periodontal disease-associated microorganisms might be helpful in revealing changes in plaque flora at the onset and conclusion of puberty. Sera was obtained from 35 subjects (ages 7 to 18 years) selected from a population of insulin-dependent diabetics. The subjects were given a thorough medical examination which included an assessment of sexual maturation and a dental examination which included the recording of onset and magnitude of bleeding according to the papillary bleeding score. Antibody titers to A. naeslundii (AN), B. intermedius (BI), B. gingivalis (BG), F. nucleatum (FN), A. actinomycetemcomitans (AA), C. ochracea (CO) and T. denticola (TD) were determined using the microELISA. Stratification of antibody titers by age groups (less than or equal to 12 years, 12 to 15 years, greater than 15 years) revealed that titers to AN increased significantly (P less than 0.025, ANOVA) and progressively (P less than 0.05, regression analysis) with increasing age. In contrast, the titers to FN were maximal in the under 12 year group and decreased with age (ANOVA, P less than 0.05; regression analysis, P less than 0.05). There were no significant variations in titers observed for the other microorganisms. Stratification by sexual maturity revealed a similar progressive decrease of the titer to FN (ANOVA, P less than 0.05; regression analysis, P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of periodontal therapy on serum antibody (IgG) levels to plaque microorganisms

The influence of periodontal therapy on serum antibody titers to selected periodontal disease-associated microorganisms was assessed in 23 patients having chronic inflammatory periodontal disease (CIPD). The immunoglobulin G (IgG) titers were determined by the microELISA technique in serum samples obtained prior to treatment; following a hygienic phase which included scaling, root planing, and oral hygiene instruction; following surgical treatment; and one year and two years following hygienic phase (maintenance phase). Considerable individual variability existed in the magnitude of immune response to specific bacterial preparations. Significant reductions in the mean antibody titers were seen to A. viscosus, S. sanguis, F. nucleatum, S. sputigena, B. gingivalis, B. intermedius, B. melaninogenicus, T. vincentii, and T. denticola by the end of the second year of maintenance. There was no consistent response to Capnocytophaga. When individual patient responses were examined, 6 of the 23 were found to have elevated titers to at least one of the microorganisms in the interval between pretreatment and the end of the hygienic phase; however, in all but one case, the titers at the end of the second year of maintenance were below pretreatment levels. Antibody levels to bacteria such as S. sanguis were modified during therapy. This would indicate that immune responses to microbes not generally considered to be "periodontal pathogens" may be modified by adjuvant activity associated with subgingival plaque or changes in the environment of the sulcus and that subsequent changes in titer do not necessarily reflect a role of that microorganism in the disease process.

Antibodies against lipopolysaccharide from Bacteroides gingivalis before and after periodontal treatment

Specific serum antibody activities of the IgG, IgA and IgM isotypes against lipopolysaccharide (LPS) prepared from Bacteroides gingivalis were measured by an enzyme-linked immunosorbent assay (ELISA) in a group of 12 periodontally healthy subjects and a group of 26 patients with periodontitis. The latter group received periodontal therapy, completed within about 1 yr. A serum sample was obtained from each participant at the first periodontal examination; a second sample was taken about 2 yr later. The mean antibody levels calculated for the healthy group did not change significantly between the first and second examination. The correlation coefficients computed between the two sets of measurements were 0.93, 0.90 and 0.96 for IgG, IgM and IgA respectively (P less than 0.05). Periodontal treatment significantly improved the clinical status of the patients and was followed by a statistically significant mean reduction in specific antibody levels to the LPS preparation (IgG: 15%, IgA: 30% and IgM: 15%).

Sensitization with Fusobacterium nucleatum targets antibody-dependent cellular cytotoxicity to mammalian cells

Incubation of mammalian tumor cells with either soluble of insoluble fractions (10 to 100 micrograms/ml) of Fusobacterium nucleatum sensitizes them to the destructive activity of antibody-dependent cellular cytotoxicity (ADCC) effector cells in the presence of anti-F. nucleatum antisera. All three types of ADCC effector cells are capable of destroying F. nucleatum-sensitized target cells with varying degrees of effectiveness (lymphocytes much greater than monocytes greater than neutrophils). Hyperimmune rabbit anti-F. nucleatum antisera were active at a dilution as high as 1/100,000. Our studies indicated that F. nucleatum must be bound to the target cells since if either the effector cells are treated with F. nucleatum or F. nucleatum is directly to an ADCC reaction, there is no significant effect on cytotoxicity. The kinetics of F. nucleatum-targeted ADCC are identical to those of classical ADCC, suggesting a similar mechanism. The specificity of F. nucleatum-targeted ADCC was demonstrated by cold target inhibition studies and by showing that other antibacterial antisera were incapable of mediating the activity.

Pretreatment with lipoteichoic acid sensitizes target cells to antibody-dependent cellular cytotoxicity in the presence of anti-lipoteichoic acid antibodies

This study was performed to determine whether antibody-dependent cellular cytotoxicity (ADCC) could be directed against mammalian cells sensitized with spontaneously adhering bacterial substances. 51Cr-labeled SB leukemia cells were incubated with purified S43 group A streptococcal lipoteichoic acid (LTA; 0.001 to 100 micrograms/ml). Purified leukocyte ADCC effector cells were added to the LTA-coated target cells at various effector-to-target ratios (100:1 to 12:1), followed by the addition of rabbit anti-LTA. After incubation for 4 h, target cell lysis was calculated based on the release of label into the medium. As little as 1 ng of LTA per ml was sufficient to sensitize the target cells to ADCC lysis (12%); however, concentrations above 0.1 micrograms/ml generally resulted in 60 to 80% lysis. LTA alone was not cytotoxic to these target cells. Targeting did not occur if effector cells were sensitized or if free LTA was added to the medium. Specificity was demonstrated by cold-target inhibition, which showed that anti-LTA cytotoxicity could be inhibited only by unlabeled, LTA-treated target cells but not by cold SB cells alone. The findings indicate that certain soluble bacterial components, when bound to mammalian cells in the presence of specific antibody, can target ADCC effectors to these cells. This mechanism may be an important factor in the delayed sequelae of bacterial infections.

Host responses to bacteria and bacterial products in periodontal disease: immunosuppressive effects of periodontitis-related microorganisms?

Several recent investigations indicate that some patients with adult periodontitis have lowered serum antibody levels or reduced lymphoproliferative responses to certain periodontitis-related microorganisms. Many such patients tend to show increased responses after therapy. Some suggested mechanisms of such responses are reviewed and the possible significance of immunosuppressive effects of periodontitis-related microorganisms are briefly discussed.

Microbe-induced lymphocyte blastogenesis enhancement after preculture

The in vitro blastogenic response of human peripheral blood mononuclear cells to Fusobacterium nucleatum and other oral microorganisms was enhanced if the peripheral blood mononuclear cells were cultured for 24 h at 37 degrees C prior to the addition of stimulant. The enhancement which occurred at optimal and supraoptimal concentrations of F. nucleatum (10 to 100 micrograms/ml) was detected after a preculture period of as little as 2 h. The blastogenic response was a result of T-cell proliferation, and enhancement occurred independently of monocytes. Suppressor activity was induced by culturing fresh lymphocytes for 24 h in the presence of supraoptimal concentrations of F. nucleatum. The enhancement phenomenon occurred independently of the prostaglandin effects on lymphocyte blastogenesis and was not abrogated by treatment with indomethacin.

Effect of periodontal therapy on spontaneous lymphocyte response and neutrophil chemotaxis in localized and generalized juvenile periodontitis patients

The etiology and pathogenesis of juvenile periodontitis may involve dysfunctions of the host response. In particular, the neutrophil and the lymphocyte have been implicated in the disease. The purpose of the present study was to examine the in vitro spontaneous lymphocyte response and neutrophil chemotaxis in populations of localized juvenile periodontitis (LJP) and generalized juvenile periodontitis (GJP) patients and age- and sex-matched healthy subjects (HS). These laboratory values were also evaluated immediately following and 1 year after periodontal therapy. The results show that spontaneous lymphocyte responses reflecting the autologous mixed lymphocyte reaction (AMLR) are depressed for GJP patients. The decreased AMLR in the GJP group appears to represent an abnormal T-cell function which may reflect activity of the periodontal lesion. LJP patients have an increased AMLR response, although it was not statistically significant. 1 year following active periodontal therapy, spontaneous lymphocyte responsiveness returned to normal in most GJP patients. The increased spontaneous lymphocyte responsiveness of LJP patients was not changed either immediately following active periodontal therapy or 1 year later. LJP and GJP patients exhibited a neutrophil chemotaxis defect when compared to cells from HS. This neutrophil defect was still observed 1 year following active therapy.