Search

Human systemic antibody levels to oral members of the Bacteroides genus were assessed with an enzyme-linked immunosorbent assay. Antibody levels to B. gingivalis, two homology groups of B. intermedius, B. melaninogenicus, B. denticola, B. loescheii, B. corporis, B. oralis, B. buccae, and B. gracilis were determined in subjects with localized juvenile periodontitis, advanced destructive periodontitis, or adult periodontitis and in normal persons. Significantly elevated serum immunoglobulin G (IgG) antibody levels to B. gingivalis were seen in adult and advanced destructive periodontitis patients. Serum IgM and IgA antibodies were increased in diseased versus normal subjects, whereas negligible levels of serum IgE antibody were detected to this microorganism. Serum IgG antibody levels to B. intermedius were increased in advanced destructive periodontitis patients; however, the frequency of elevated responses were similar among the groups. Extreme antibody levels to the other Bacteroides spp. were occasionally observed in this population. Additionally, all of the elevated levels were found in diseased patients. Distribution analyses of the antibody levels indicated that most patients exhibited a pattern of elevated antibodies to a limited number of the oral Bacteroides spp. The results suggested that elevated systemic antibody levels to oral Bacteroides spp. are more frequently found in periodontal disease patients. These antibody responses presumably reflect a colonization of the patients. The distribution of the responses may indicate the potential pathogenicity of the microorganisms and is consistent with distinctive host-parasite interactions in this disease.

The indigenous flora acts as a deterrent to the establishment of some pathogenic species. We propose that advances in oral health research will lead to control of oral infections by altering the indigenous microflora to create a specific pathogen-free human. Investigations of important endogenous and exogenous factors which affect the oral flora and the interactions among these parameters, in health and disease, will have to be undertaken for this goal to be achieved. Several approaches to produce a specific pathogen-free human include: (1) introduction of individual or collective moieties which inhibit detrimental interactions on a genetic and molecular level; (2) genetic modification of salivary flow and protein composition by use of transgenic techniques; (3) therapeutic replacement with altered bacterial strains; (4) alteration of host immune responses to produce specific isotype immunity at the most appropriate time in the ontogeny of the oral environment; (5) production of isotype and/or antigen-specific regulatory molecules at the most appropriate time in development; (6) use of synthetic vaccines; (7) genetic alteration or replacement of cells with defective protective capabilities; and (8) use of anti-idiotype vaccines.

The salivary antibody response produced after remote secretory site (mammary gland) injection of soluble or particulate DNP antigens was examined in the rat. IgA and IgG salivary antibody and IgG serum antibody concentrations were determined by an ELISA technique. Two experiments were performed using DNP-BGG as the soluble antigen and either DNP-S. mutans or DNP-BGG-S. mutans as particulate antigens. Approximately equivalent IgA antibody responses were produced when soluble or particulate antigens were injected locally at a secretory site. However, a greater salivary IgA response was observed with the soluble antigen when the antigens were injected in the vicinity of a secretory site (mammary glands) remote from the salivary glands (experiment 1: 123 +/- 46 vs 2 +/- 1 ng IgA per millilitre of saliva, and experiment 2: 212 +/- 59 vs 45 +/- 21 ng IgA per millilitre of saliva). In both experiments, prior remote secretory site injection of the soluble antigen was able to prime for a significantly increased salivary IgA response (more than three-fold) after a local injection in the vicinity of the salivary gland. The particulate antigens did not lead to priming of the salivary antibody response. Prior remote secretory site injection of soluble antigen, but not of the particulate antigens, also increased salivary and serum IgG antibody levels above the levels observed with an injection at either site alone.

The effect of oral administration of glucosyltransferase (GTF) from Streptococcus sobrinus 6715 on levels of immunoglobulin A (IgA) antibody to GTF in parotid saliva and on the number of indigenous Streptococcus mutans in the whole saliva was studied in young adult males. GTF combined with aluminum phosphate (AP) was administered in capsules to 14 subjects, while sodium phosphate buffer combined with AP was administered in the same way to 11 control subjects. Thirteen administrations were given during the first immunization regimen, and five administrations, approximately 3 months later, constituted the second immunization regimen. All subjects were given professional dental prophylaxis immediately prior to each immunization. Each subject served as his own control by using antibody and bacterial data collected prior to antigen administration for comparison. After the first immunization regimen, the GTF vaccine group exhibited a significantly higher distribution (P less than 0.05) of normalized parotid saliva IgA antibody elevations than observed in the placebo group. Between the first and second immunization regimens a significant increase (P less than 0.05) in parotid salivary anti-GTF activity also occurred in the GTF vaccine but not the placebo group. No significant differences between these two groups were observed on any occasion when serum IgG or IgA antibody to GTF was analyzed. Comparison of the group mean log ratios (post- to prevaccine administration) of S. mutans to total streptococci in whole saliva revealed that the GTF vaccine group values were always lower than those of the placebo group. These differences reached significance (P less than 0.01) on three of the last four sampling occasions (days 21, 35, and 42) following initiation of the first immunization regimen. The mean log ratios of the GTF vaccine group were also lower than those of the placebo group after the second immunization regimen but did not reach significance. These data indicate that oral administration of GTF from the mutans streptococci has the potential to elicit a salivary IgA antibody response when combined with an aluminum-based adjuvant and that this response can interfere with the reaccumulation of indigenous S. mutans following dental prophylaxis.

A technique for the characterization of rat gingival lymphocytes has been described. The technique was used to obtain gingival cells from rats maintained on antigen-free diets or such diets with ovalbumin (OVA) added. Increases in gingival lymphocyte numbers in the antigen-fed (AF) animals occurred by 16 to 23 days of OVA feeding. The elevated gingival lymphocyte numbers were predominantly T lymphocytes at the initial intervals of the experiment (to 59 days of OVA feeding). At 128 days of OVA feeding T-lymphocyte numbers diminished but B-lymphocyte numbers increased, and AF animals had more than six times as many gingival B lymphocytes as animals not fed antigen. Also, AF animals showed immunoglobulin A antibody in intestinal perfusates (after 9 days of OVA feeding) and in saliva (within 23 days of OVA initiation). Plasma immunoglobulin G antibodies were not detected until 59 days of feeding. Spleen cells from AF rats showed in vitro blastogenic responses to OVA at 23 to 59 days of feeding. Periodontal bone loss was greater in AF animals after 59 and 128 days of OVA. Germfree animals fed only one antigen experienced more periodontal bone loss than animals fed the same diet not containing antigen. Therefore, immune phenomena can contribute to experimental bone loss in germfree rats.

The effect of neonatal thymectomy on salivary and serum antibody responses was studied in rats. Local immunization of thymectomized rats with a T-dependent antigen (DNPBGG) elicited negligible amounts of IgA anti-DNP antibody in saliva. In contrast, both normal and sham-thymectomized animals demonstrated substantial levels of salivary IgA antibody. All thymectomized rats locally injected with a T-independent antigen (DNP-Lys-Ficoll) exhibited salivary IgA antibody production. Salivary IgG antibodies were somewhat decreased in thymectomized rats injected with either antigen; however, the final effect of T cell deprivation on IgG synthesis was not as pronounced as on IgA synthesis. Serum IgA antibody was induced in control rats injected with DNPBGG, whereas this Ig class of antibody was absent in thymectomized rats. The results suggest that thymus-derived cells exert a regulatory influence on both serum and secretory IgA responses to antigens.

A rapid method for identifying black-pigmented oral Bacteroides spp. is described. Species-specific rabbit antisera to Bacteroides gingivalis, B. intermedius, and B. melaninogenicus were used in an enzyme-linked immunosorbent assay to identify clinical isolates of black-pigmented Bacteroides spp. from humans. The results showed excellent agreement with biochemical identification of B. gingivalis and B. intermedius. Only 36% of the B. melaninogenicus isolates were identified with the enzyme-linked immunosorbent assay, suggesting that this group of black-pigmented Bacteroides spp. is made up of more than one serotype. The serological enzyme-linked immunosorbent assay should enable rapid identification of black-pigmented Bacteroides spp. isolated from sites of oral diseases and may also be used to identify the presence of these organisms in complex bacterial mixtures from oral sites.

The phenotypic distribution of lymphocytes and mononuclear phagocytes resident in rat secretory glands was examined. Isolated exocrine gland mononuclear leucocyte populations contained 50-61% W3/13+ T cells and greater proportions of W3/25+ T helper cells relative to OX8+ T suppressor cells. Surface Ig+ cells (sIg) constituted from 32% to 34% of the cells and their distribution was sIgM greater than sIgA greater than sIgG. The macrophage populations comprised from 0.02% to 0.1% of the unfractionated gland cells. Fractionated secretory gland-adherent cells consisted primarily of non-specific esterase+, phagocytic and Fc receptor-bearing cells. From 35% to 79% of the macrophages in exocrine glands expressed I-A molecules. The results suggest that exocrine glands have the ability to respond locally to an antigenic challenge independently of a central mucosal immune response.

Salivary IgA responses of rats receiving MDP were elevated after oral GTF administration and after infection with S. mutans bearing surface GTF. Intragastric administration (but not injection) of MDP enhanced salivary IgA responses to i.g. GTF. Subcutaneous injection (but not i.g. administration) of MDP enhanced IgA responses to GTF injected in the salivary gland vicinity. Conjugation of MDP to GTF did not enhance the secretory response to the antigen. Nevertheless, s.g.v. administration of OVA in IFA dramatically enhanced the secretory and serum responses. Injection of MDP may further enhance the secretory response. The combination of routes of adjuvant and antigen administration were critical in selectively enhancing a secretory immune response.

The distribution of immunoglobulin-containing cells (ICC) of the immunoglobulin A (IgA), IgG, and IgM isotypes was examined in various lymphoid and secretory tissues of rats. The effect of neonatal thymectomy of rats on T cells, B cells, and ICC in these tissues was determined by immunofluorescence. The results showed that although T cells were severely depleted in both lymphoid and secretory tissues of the thymectomized (Tx) rats, Tx and normal rats showed comparable numbers of B cells staining for IgA, IgG, and IgM. After neonatal thymectomy, IgA ICC in both lymphoid and secretory tissues were significantly decreased. However, the Tx rats exhibited a compensatory increase in IgM ICC in the identical tissues. Local injection of normal and Tx rats with Streptococcus mutans 6715 resulted in an increase in all isotypes of ICC in the secretory tissues. Although the primary increase in normal rats was due to IgA ICC, Tx rats exhibited the greatest change in the number of IgM ICC.

The effects of immunization with antigens of the Streptococcus mutans glucosyltransferase (GTF) complex on oral challenge with two Streptococcus sanguis strains (H7PR3 and 34) in hamsters were studied. Antisera to S. mutans GTF complex were able to inhibit one-third (strain H7PR3) to one-half (strain 34) of the S. sanguis GTF activity which could be inhibited when these S. sanguis GTFs were incubated with antisera to S. sanguis GTF. Washed, intact cells of strains H7PR3 and 34 were able to remove a significant amount of enzyme inhibitory activity and immunoglobulin G antibody activity from antisera to S. mutans GTF. These results established the existence of an antigenic relationship between S. sanguis and S. mutans GTFs. The effect of injection of S. mutans strain 6715 GTF or phosphate-buffered saline, incorporated into complete Freund adjuvant, on oral challenge with S. sanguis was compared in 243 hamsters in nine experiments. Salivary and serum GTF inhibitory activity was present in all GTF-injected animals before challenge. After a 2- or 3-day challenge with S. sanguis H7PR3 (seven experiments) or 34 (two experiments), fewer bacteria were recovered from GTF-injected hamsters in every experiment. Significant differences were observed in six of the nine experiments. During the 7- to 21-day period after challenge, 33% of the phosphate-buffered saline-injected sham group (group I) still had S. sanguis recoverable from the molar surfaces, whereas only 19% of the S. mutans GTF-injected group (group II) remained infected with S. sanguis (P less than 0.01). These results suggest that immunization with GTF from S. mutans may influence the colonization potential of S. sanguis in the oral cavity.

Salivary IgA antibody to poliovirus and tetanus toxoid was measured in whole salivas of 151 children between 2 and 48 months of age from North America and from Scandinavia. Children from urban and suburban populations in the greater Boston, MA, area receive both oral poliovaccine and a parenteral injection with tetanus toxoid (TT), initially at approximately 2 months of age. Children from Göteborg, Sweden, initially receive parenteral injections of TT at 2 months of age and parenteral injections of killed polio vaccine initially at 9 to 10 months of age. Twenty-six percent of the Boston subjects who were less than 12 months old had detectable salivary IgA antibody to poliovirus after oral immunization. In contrast, within the first year after parenteral immunization with killed poliovirus, the Swedish group had detectable salivary antibody in 9% (1 of 13) of the subjects. Forty to 65% of the children in the older Boston-area age groups had positive salivary IgA antibody levels to this antigen. No differences were seen in salivary IgA antibody to TT among the three populations. By 36 months of age at least 50% of all populations had detectable salivary antibody to TT. The ratio of enzyme-linked immunosorbent assay (ELISA) activity using rabbit anti-human secretory component versus rabbit anti-human alpha chain was significantly higher in subjects less than 12 months of age compared with older groups. This suggested either that free secretory component was binding to tetanus toxoid or that secretory antibody of isotypes other than IgA was present in these youngest subjects.

Experiments were performed to determine the role of the immune response in rat periodontal disease. Germ-free rats were fed defined antigen-free liquid diets or a diet containing ovalbumin(OVA) as a prototype antigen. The OVA-fed rats demonstrated increased gingival lymphocytes (mainly T at early times), OVA-sensitized spleen cells, and increased periodontal bone loss. In further studies, rats pre-sensitized with OVA, and receiving OVA in the diet, showed elevated IgG antibody, sensitized spleen cells, and elevated periodontal bone loss scores. The concept that bone loss was due to mixed hypersensitivity reaction is consistent with the periodontal pathology. The effects of pre-immunization with A. actinomycetemcomitans (Aa) on periodontal bone loss in Actinobacillus (Aa) - infected rats was examined. Delayed hypersensitivity (DTH) was present in immunized rats throughout the experimental period. Sham-immunized rats showed DTH after 30 days of infection. In addition, immunized rats showed elevated bone loss scores. These experiments support the contention that a combination of hypersensitivity reactions (i.e., mixed hypersensitivity to Aa) could give rise to the periodontal pathology observed. Congenitally athymic rats (nude) were shown to have more periodontal bone loss than did normal littermates. However, bone loss in thymus-cell reconstituted nude rats was not different from that in control rats. Normal rats receiving Aa-sensitized T lymphocytes prior to infection with Aa demonstrated increased DTH and periodontal bone loss. These studies support the concept that T-cell functions and thymic regulation of immune responses can exert protective and/or destructive effects in periodontal disease. In order to modify disease, it will be necessary to enhance the protective aspects of the immune response and to minimize the detrimental aspects.

The effect of neonatal thymectomy on secretory and systemic antibody responses in rats was studied. Groups of normal or thymectomized (Tx) rats were infected or immunized and infected with Streptococcus mutans 6715. Tx rats exhibited a significantly lower level of salivary immunoglobulin A (IgA) antibody to S. mutans after a 45- to 65-day infection. Similarly, after multiple local injections of formalinized S. mutans, Tx rats showed a delay in the appearance and lower levels of salivary IgA antibody to S. mutans. Serum IgG antibody levels were also decreased in Tx rats with both experimental protocols. In contrast, salivary IgG and serum IgM anti-S. mutans activity in Tx and normal rats were similar during the experiments. These results demonstrated that thymus deprivation at birth produces profound effects on the ability of rats to manifest secretory IgA antibody responses to the pathogenic microorganism S. mutans.

This study probed the influence of antigenic exposure on the immunological response of the lacrimal gland. We utilized the germfree rat as a model system to monitor tissue and tear immunoglobulin changes following transfer of these animals into an antigen-laden, conventional environment. The number of IgA- and IgM-containing cells in the lacrimal glands of germfree rats was 5 to 8 fold less than that of conventional controls. This reduced immunological expression in germfree animals also extended to tear IgA levels, which were significantly decreased. No effect of germfree conditions was found on the tear content of secretory component (SC). Transfer of rats from a germfree to a conventional environment resulted in a significant increase in the number of IgA- and IgM-containing cells in the lacrimal gland. By four weeks after 'conventionalization', the number of Ig-containing cells in lacrimal tissue was similar in both ex-germfree and conventional rats. In addition, 'conventionalization' led to a significant increase in the tear content of IgA: within four weeks following exposure to a conventional environment, tear IgA levels in ex-germfree rats were equivalent to those of age-matched, conventional controls. Overall, our results demonstrate that the secretory immune system of the lacrimal gland reacts to antigenic challenge with an increased immunological response.

The association between periodontal disease in humans and serum and salivary antibody to Actinobacillus actinomycetemcomitans strain Y4 was determined. An Elisa was used to examine anti-Y4 antibody of the IgM, IgG, IgA and IgE isotypes in serum from 127 individuals and IgA in parotid saliva. Patients diagnosed as having localized juvenile periodontitis (n = 37) had significantly higher levels and frequency of serum IgG antibodies to Y4 than all other groups. Serum and salivary IgA and serum IgE antibody levels were significantly increased in patients with both localized and generalized types of juvenile periodontitis (n = 48) when compared to all other patient groups. Specificity studies suggested that the antigenic determinants that were differentiating the group responses were unique to the Y4 organism. These results indicate that serum antibodies to Y4 may reflect an infectious process with this micro-organism and that these responses may provide some diagnostic value in delineating different types of periodontal diseases.

Antibodies to S. salivarius, S. sanguis, and S. mutans cells and to glucosyltransferases (GTF) prepared from these micro-organisms were measured in the sera of 133 infants and children by enzyme-linked immunosorbent assay (ELISA). IgG antibody activity to each cell type and GTP was present at birth (presumably derived from maternal transfer) and declined significantly thereafter. IgG antibody levels to S. salivarius and S. sanguis were next detected in young children (2 to less than 3 yr group). However, an increase in IgG antibody to S. mutans cells was not seen until children were older (4 to less than 8 yr group), possibly reflecting the later colonization of this organism. In contrast, IgG antibody to GTF of all three streptococcal species remained at low levels throughout the first four years of life. IgG antibody to S. mutans GTF was then the first to appear (4 to less than 8 yr group). Serum IgA antibodies to all GTFs were not detected until after this time. Fifteen sera were used to develop IgG immunoblots with the GTF antigens. Some positive sera (7/12) demonstrated reaction(s) with GTF from each of the three streptococcal species. Individual sera showed IgG antibody bonds to GTF from several serotypes of the mutans streptococci. No immunoblot reaction was observed with GTF and sera (3) from the four-to-seven-year and younger age groups. These results indicate the presence of serum antibody to bacteria and bacterial products associated with plaque formation very early in life and during and after the pre-adolescent years. The potential exists for this serum antibody to modulate bacterial colonization or accumulation in the oral cavity.

The levels of immunoglobulins (Ig) in the serum and saliva of nude (rnu/rnu), congenitally athymic rats and control (rnu/+) rats were studied after injection in the vicinity of the salivary glands with several different T-dependent or T-independent dinitrophenylated antigens. Serum IgG levels were higher in rnu/+ rats than rnu/rnu rats after both primary and secondary immunizations. WHile serum IgM levels were higher in rnu/+ rats after primary immunization, secondary immunization with the most thymic-dependent antigens elicited higher IgM levels in rnu/rnu rats. After primary immunization, serum IgA levels in rnu/rnu rats were significantly lower than rnu/+ levels but no differences between the groups were noted after secondary immunization. Primary immunization with these antigens also demonstrated a markedly reduced salivary IgA producing capability by the athymic rats. Importantly, no such differences in serum or salivary IgA were previously found in the absence of immunization. Thus, immunization accentuated differences in Ig level and isotype distribution between rnu/rnu and rnu/+ rats.

Acquired pelicle appears to contain primarily IgA and other proteins of salivary origin. With the increased time necessary for plaque formation, gingival crevicular fluid contributes proteins to the growing plaque accumulation. However, secretory IgA is still the major intact immunoglobulin in plaque samples since appreciable portions of the molecules bearing IgG determinants appear to be degraded to small fragments. Nevertheless, the amount of IgA present in plaque, which could be considered antibody, is too little to account for most of the plaque interactions. Since secretory IgA appears to be resistant to proteolytic degradation by a mixture of plaque enzymes, and IgA fragments are not prominent in plaque extracts, degradation of secretory IgA probably cannot explain the relatively low IgA levels in plaque. It has been shown that salivary IgA antibody can interfere with enzymes responsible for the plaque-forming potential of certain organisms. All the preceding evidence is consistent with our current contention that secretory IgA functions as blocking antibody to interfere with the formation of dental plaque. This could occur by direct inhibition of bacterial polymer formation or by direct or indirect inhibition of bacterial interaction with salivary constituents by secretory IgA. Less than 1% of the plaque interactions can probably be attributed to secretory IgA antibody. IgG may contribute even less since it is degraded.

The effect of local immunization with glucosyltransferase enzymes of Streptococcus mutans on dental caries in conventional rats, hamsters, and gnotobiotic rats was studied. Injection of these animals with crude or defined glucosyltransferase enzyme preparations incorporated into complete Freund's adjuvant consistently resulted in the presence of antibody in saliva demonstrable by functional inhibition of enzymatic activity and binding of radioactive enzyme. Serum antibody was also present. Two experiments have been completed in conventional rats and one in gnotobiotic rats in which the animals were immunized with crude enzyme antigens. The immunized groups of animals always had lower mean caries scores than comparably sham-immunized or nonimmunized control groups. Hamsters immunized with a defined enzyme preparation, containing no more than three antigenic components (two of which were enzyme), also demonstrated significant reductions in mean caries scores. The numbers of lesions were also always lower in immunized animals. In some cases there were reductions in the numbers of S. mutans that could be recovered from the teeth of immunized, infected animals. The reductions in dental caries and lesions were greater on smooth dental surfaces than on occlusal surfaces, which might be explained as interference with adherence phenomena demonstrated by S. mutans. It is proposed that antibody interference affects dental caries caused by this organism.

Taken together, the immunization experiments which have been performed in the rat caries model system appear to suggest a correlation between the presence of salivary antibody to S mutans and reductions in caries caused by these bacteria. However, the multifactorial nature of this disease does not permit at present the conclusion that the presence of this antibody is both necessary and sufficient to give rise to the demonstrated effects on pathogenesis. To clarify the role of salivary antibody, several refinements may be required in the current model. Immunization procedures that elicit only a local antibody response would both simplify interpretations of effects and would be more desirable for use as a vaccine. Such procedures might include intraductal installation of antigen in the parotid gland which has been demonstrated to result in this type of response. An additional refinement stems from the knowledge that the kinds of immunization procedures currently used stimulated both cellular immune and soluble antibody systems, potentially giving rise to a rather broad spectrum of immune responses. Therefore, it might be useful to study the effects on S mutans pathogenesis in rats in which certain of these responses have been repressed, for example, by thymectomy, antilymphocyte serum, and so on. Also, each of these approaches would be measurably enhanced by more sensitive techniques to monitor immunological events in the oral cavity. Refinements in the selection and use of relevant antigens of S mutans also are necessary to delineate the in vivo mechanism of immunological interference in the pathogenesis of cariogenic streptococci. Approaches involve the use of purified GTF antigens or cell surface antigens both in the investigation of these mechanisms in in vitro models using antibody specifically directed to these antigens and in rat immunization experiments using immunogenic preparations of these materials. In addition, alterations in the diet and challenge dosage of infecting cariogenic organisms might permit more sensitive detection of effects in vivo. Clearly, the evidence suggests immunological interference with S mutans pathogenesis in the rat model system. However, several gaps exist in our basic understanding of this interference and of the appropriate system in which to observe these effects. The potential significance of this phenomenon should spur efforts to fill these gaps to establish definitively the role of immunity as an ecological determinant in the oral cavity.

The objective of the present study was to evaluate the capacity for secretory immune responses throughout life. This was done by measuring, by single radial immunodiffusion, the concentrations of IgA and IgA1 subclass in saliva samples of subjects who ranged in age from two months to 91 years. The presence of salivary IgA antibodies to two nearly ubiquitous mucosal antigens, Streptococcus mutans glucosyltransferase (GTF) and killed poliovirus (Types 1, 2, and 3), was measured in an enzyme-linked immunosorbent assay in this population. Whole saliva from 2-5-month-old infants contained significantly less IgA than did parotid saliva of any adult group. Also, a significantly higher proportion of the total salivary IgA was IgA1 in infants' saliva than was found in parotid saliva of adults. Salivary IgA and IgA1 subclass levels in parotid saliva of young and old (70-91 years) adults did not differ. Salivary IgA antibody levels to GTF were negligible in most saliva samples of children less than five years old, while 40% of children older than one year had detectable levels of salivary antibody to poliovirus (PV). This differences between response to GTF and PV antigens may reflect differences in antigenic challenge. Parotid saliva of the oldest group (70-91 years) had narrowly distributed and uniformly low levels of IgA antibody to both antigens. Since their IgA immunoglobulin levels were the same as in younger adults, the low antibody levels in this oldest group may be associated with changes in the number or function of T or B lymphocytes or antigen-processing cells, and/or may result from diminished levels of challenge with these antigens.

The effect of neonatal thymectomy on the level of salivary and serum immunoglobulins was studied in conventional rats. Salivary SIgA levels were significantly decreased from weaning (day 20) through the termination of the experiment, while salivary IgG levels were generally unaffected by neonatal thymectomy. Serum IgA was detected at a later interval after birth in samples from thymectomized rats than from normal and sham-thymectomized rats and the levels of serum IgA in the thymectomized rats remained 4-5 times lower throughout the 115 day experimental period. Serum IgG was decreased by approximately 40% from days 28 through 115 after birth in the thymectomized animals, while serum IgM was apparently unaffected by the neonatal thymectomy. These findings indicate that the synthesis of salivary SIgA is markedly influenced by the presence of thymus-derived cells and it is suggested that these cells may control and/or modify immune responses in oral secretions.

Whole saliva samples from 17 infants who were between 3 and 20 weeks of age were analysed for isotype, subclass and molecular size of immunoglobulins. IgA concentrations ranged from 1.7 to over 60 micrograms/ml. IgM concentrations ranged from undetected to 59% of the IgA concentration in the respective saliva. Ratios of salivary IgM to salivary IgA were inversely correlated with the age of the infant. Gel filtration of 31 salivas on calibrated columns of Superose 6 revealed the IgA to elute in a position consistent with that of secretory IgA. IgM eluted in a position consistent with that of the pentameric molecule. IgA1 was the predominating subclass (IgA1/IgA1 + IgA2 = 0.64) in infant whole saliva. Both IgA subclass concentrations were significantly lower than concentrations measured in adult parotid salivas. Several infant salivas initially contained greater than 95% IgA1 but salivary IgA2 concentrations progressively increased as these infants grew older. These observations support the conclusions that essentially all IgA in whole saliva of predentate infants is of secretory origin, that adult salivary IgM/IgA proportions are achieved early in life, but that, at least in some infants, the salivary IgA subclass proportions are still changing during this time.

The salivary and serum immune responses to orally administered glucosyltransferase antigen complex from Streptococcus mutants strain 6715 were investigated in hamsters. All enzyme-linked immunosorbent assay was used to measure the antibody quantity and isotype, and a [14C]glucosyl-labeled sucrose incorporation assay was used to measure functional inhibition of the enzyme. A total of 21 to 27 daily doses of antigen administered in hamster oral cavities elicited salivary immunoglobulin C and immunoglobulin A antibody responses and functional inhibitory activity. The salivary response increased throughout the immunization procedure, and the amount of salivary antibody was dependent upon the dose of antigen given. The salivary response to a second oral administration of antigen for 4 days showed some features of anamnesis. The response after a second antigen administration was detected sooner than the primary response, and somewhat higher levels of antibody and inhibitory activity were observed. Serum antibody (immunoglobulin G and immunoglobulin M) and functional inhibitory responses were also elicited by oral administration of the soluble enzyme antigen. These responses were lower than responses induced by local injections of antigen in complete Freund adjuvant. The ability to evoke a salivary immune response to the glucosyltransferase antigen complex may increase the potential of using this antigen in an effective caries vaccine.

76 subjects with prior evidence of destructive periodontal diseases were monitored clinically and immunologically every 2 months for up to 5 years. Clinical parameters measured included bleeding on probing, gingival redness, plaque accumulation, suppuration, pocket depth and attachment level. Blood samples were taken by venipuncture and serum antibody levels to a series of 18 subgingival species determined. 33 of these subjects showed evidence of active disease during the monitoring period, based on changes in attachment level measurements assessed using the tolerance method of analysis. Mean attachment loss in these 33 subjects varied from 1.4 mm to 9.0 (median value 3.4 mm) and subjects whose mean attachment level was above the median showed a higher % of pockets greater than 3 mm and more suppuration. Severity of gingival inflammation related poorly to mean attachment loss. Subgingival plaque samples were taken from the active site(s) and from control sites of equal pocket depth and attachment loss in the same active disease subjects, prior to therapy, for predominant cultivable microbiota studies. 50 randomly selected isolates were identified from each sample. Predominant cultivable species in 170 pretreatment active and inactive sites combined (8500 isolates) were enumerated. The most frequently detected species were F. nucleatum (112 sites) and S. intermedius (106 sites), although the predominant species in the samples from each subject differed. The distribution of putative pathogens differed among subjects. For example, A. actinomycetemcomitans was found in 21 samples in 11 subjects and B. forsythus was found in 18 samples from 10 individuals. Antibody response patterns to the 18 subgingival species also varied among subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

27 subjects with active destructive periodontal diseases were treated by modified Widman flap surgery and systemic tetracycline and divided into 4 groups based on pre- and post-therapy hazard rates (% of sites losing greater than 3 mm of attachment in 1 year). Pre- and post-therapy hazard rates were respectively: group I (3 subjects) less than 4 and less than 4; group II (8 subjects) greater than 4 and less than 4; group III (3 subjects) less than 4 and greater than 4; group IV (refractory group of 13 subjects) greater than 4 and greater than 4. Baseline mean pocket depths and attachment loss of groups I and II subjects were less than groups III and IV subjects and exhibited less suppuration. 6 group IV subjects lost a total of 38 teeth after therapy, in contrast to no tooth loss in subjects in the other 3 groups. Redness, bleeding on probing, plaque levels and age did not differ among groups. Subjects in the 4 groups differed in the subgingival species to which they showed elevated serum antibody responses. Group IV subjects showed elevated responses to a select range of gram-negative species, including A. actinomycetemcomitans strains Y4 or ATCC 29523, F. nucleatum and B. intermedius. No subject in any of the other groups exhibited an elevated response to B. intermedius. The mean % of each species in all sampled sites, both before and after therapy, was computed for each subject. Subjects in groups III and IV (high post-therapy hazard rates) exhibited elevated mean levels of B. forsythus, F. nucleatum, S. intermedius, E. corrodens, and B. gingivalis.(ABSTRACT TRUNCATED AT 250 WORDS)

The antigenic relationship of glucosyltransferases (GTF) produced by different serotypes of Streptococcus mutans was studied by using a functional inhibition assay. Rat, rabbit, or hamster immune fluids, directed to cell-associated or supernatant-derived GTF, were tested against ammonium sulfate-precipitated culture supernatants containing GTF from seven strains of S. mutans representing six different serotypes. An antigenic relationship was shown to exist among GTF from serotypes a, d, and g, since both rat and rabbit antisera directed to serotype a or g GTF inhibited GTF of serotypes d and g similarly and both antisera also inhibited serotype a GTF. Furthermore, serum inhibition patterns indicated that GTF of serotypes c and e, and possibly b, are antigenically related to each other, but are antigenically distinct from GTF of serotype a, d, or g. Serum antibody directed to antigens other than enzyme (e.g., serotype-specific antigen or teichoic acid) had little effect on the inhibition assay. Salivas from rats immunized with cell-associated or supernatant-derived GTF exhibited low but consistent inhibition of GTF activity, which generally corresponded to the serum patterns. The sera of two groups of hamsters immunized with GTF (serotype g), enriched either in water-insoluble or water-soluble glucan synthetic activity, gave patterns of inhibition quite similar to those seen with sera from more heterogenous cell-associated or crude supernatant-derived GTF preparations. Both groups of hamster sera also gave virtually identical patterns, suggesting that the two enzyme forms used as antigen share common antigenic determinants. The results from the three animal models suggest that among the cariogenic organisms tested, two (serotypes a, d, g and b, c, e), or perhaps three (serotypes a, d, g; b; and c, e), different subsets of GTF exist that have distinct antigenic determinants within a subset.

1. The reactions of beta-propiolactone with amino acids were investigated under various conditions of pH and temperature to find those under which the reagent acted with specificity. 2. At pH9.0 and 22 degrees , after 15min. of reaction, at least 85% of each amino acid had reacted, methionine and cystine being the most reactive. 3. At pH7.0 and 22 degrees most amino acids reacted; methionine, cystine and histidine reacted almost entirely, and proline and lysine to a significantly smaller extent. 4. At pH3.0 and 22 degrees further specificity was obtained; methionine and cystine were the only reactive amino acids. 5. Reaction at pH3.0 and 0 degrees was specific for methionine; it was the only amino acid modified even after 145hr. of reaction.