Infection with the bacterium Streptococcus mutans and salivary IgA antibodies in mothers and their children

Correlation of s-IgA and IL-6 Salivary with Caries Disease and Oral Hygiene Parameters in Children

This study evaluates salivary immunoglobulin A (s-IgA) and interleukin 6 (IL-6) in saliva of children and its correlation to tooth decay severity. Fifty-nine patients were divided into two groups: caries free (A group) and caries active (B group). B group was investigated according to Mount and Monse indices. Mean salivary IgA rate between two groups (A 16.7 ± 4.5 mg/dL vs. B 21.8 ± 12.9 mg/dL) was not significant, while IL-6 rate (A 19.02 ± 5.3 pg/mL vs. B 30.2 ± 11.8 pg/mL) was statistically different. This study revealed that salivary IL-6 levels were significantly higher in children with active caries when compared with the caries-free group, while the s-IgA rate showed no significant differences between the two groups.

Levels and complexity of IgA antibody against oral bacteria in samples of human colostrum

Streptococcus mutans (SM) have three main virulence antigens: glucan binding protein B (gbpB), glucosyltransferase (Gtf) and antigens I/II (Ag I/II) envolved in the capacity of those bacteria to adhere and accumulate in the dental biofilm. Also, the glycosyltransferases 153 kDa of Streptococcus gordonii (SGO) and 170kDa of Streptococcus sanguinis (SSA) were important antigens associated with the accumulation of those bacterias. Streptococcus mitis (SMI) present IgA1 protease of 202 kDa. We investigated the specificity and levels IgA against those antigens of virulence in samples of human colostrum. This study involved 77 samples of colostrum that were analyzed for levels of immunoglobulian A, M and G by Elisa. The specificity of IgA against extracts of SM and initials colonizators (SSA, SMI, SGO) were analyzed by the Western blot. The mean concentration of IgA was 2850.2 (±2567.2) mg/100 mL followed by IgM and IgG (respectively 321.8±90.3 and 88.3±51.5), statistically different (p<0.05). Results showed that the majority of samples had detectable levels of IgA antibodies to extracts of bacteria antigens and theirs virulence antigens. To SM, the GbpB was significantly lower detected than others antigens of SM (p<0.05). High complexities of response to Ags were identified in the samples. There were no significant differences in the mean number of IgA-reactive Ags between the antigens (p>0.4). So, the breast milk from first hours after birth presented significant levels of IgA specific against important virulence of antigens those oral streptococci, which can disrupt the installation and accumulation process of these microorganisms in the oral cavity.

Factors influencing oral colonization of mutans streptococci in young children

This paper aims to critically review current knowledge about the key factors involved in oral colonization of the cariogenic group of bacteria, mutans streptococci (MS) in young children. MS, consisting mainly of the species Streptococcus mutans and Streptococcus sobrinus, are commonly cultured from the mouths of infants, with prevalence of infection ranging from around 30 per cent in 3 month old predentate children to over 80 per cent in 24 month old children with primary teeth. MS is usually transmitted to children through their mothers, and the risk of transmission increases with high maternal salivary levels of MS and frequent inoculation. Factors that affect the colonization of MS may be divided into bacterial virulence, host-related and environmental factors. Complex interaction among these factors determine the success and timing of MS colonization in the child. As clinical studies have shown that caries risk is correlated with age at which initial MS colonization occurred, strategies for the prevention of dental caries should include timely control of colonization of the cariogenic bacteria in the mouths of young children.

Characterization of salivary immunoglobulin A responses in children heavily exposed to the oral bacterium Streptococcus mutans: influence of specific antigen recognition in infection

The initial infection of children by Streptococcus mutans, the main pathogen of dental caries, depends on the ability of S. mutans to adhere and accumulate on tooth surfaces. These processes involve the adhesin antigen I/II (AgI/II), glucosyltransferases (GTF) and glucan-binding protein B (GbpB), each a target for anticaries vaccines. The salivary immunoglobulin A (IgA) antibody responses to S. mutans antigens (Ags) were characterized in 21 pairs of 5- to 13-month-old children. Pairs were constructed with one early S. mutans-infected and one noninfected child matched by age, racial background, number of teeth, and salivary levels of IgA. Specific salivary IgA antibody response and S. mutans infection levels were then measured during a 1-year follow-up. Robust responses to S. mutans were detected from 6 months of age. Salivary IgA antibody to AgI/II and GTF was commonly detected in salivas of all 42 children. However, GbpB-specific IgA antibody was seldom detected in the subset of infected children (38.1% at baseline). In contrast, most of the subset of noninfected children (76.2%) showed GbpB-reactive IgA antibody during the same period. Frequencies of GbpB responses increased with age, but differences in intensities of GbpB-IgA antibody reactions were sustained between the subsets. At baseline, GbpB-reactive IgA antibody accounted for at least half of the total salivary IgA S. mutans-reactive antibody in 33.3 and 9.5% of noninfected and infected children, respectively. This study provides evidence that a robust natural response to S. mutans Ags can be achieved by 1 year of age and that IgA antibody specificities may be critical in modulating initial S. mutans infection.

Neuroendocrine regulation of salivary IgA synthesis and secretion: implications for oral health

Secretory immunoglobulin A (S-IgA) represents the main adaptive immune mechanism in the oral cavity. The regulation of secretion and synthesis of S-IgA is not only dependent on prior antigenic stimulation, but is also under strong neuroendocrine control. Thus, alterations in neuroendocrine functioning (such as induced by stress, exercise, pregnancy, menstrual cycle, and pharmacological interventions) may affect salivary IgA levels. This review deals with the neuroendocrine regulation of synthesis and secretion of salivary IgA and its potential role in the maintenance of oral health.

Immunoglobulins in saliva of preterm and full-term infants

The aim of this longitudinal study was to determine salivary levels of total IgA, IgG and IgM in 84 preterm and 214 full-term infants, from birth to 18 months of age. Unstimulated whole saliva was collected from each infant at birth, and subsequently at 3-monthly intervals. Immunoglobulin levels were estimated using an ELISA technique. At birth, IgA was detected in 147/214 (69%) full-term infants but only 47/84 (56%) preterm infants (P < 0.01). In the case of IgG, 61% of full-term and 56% of preterm infants showed detectable levels, whereas IgM was found in 71% and 73%, respectively. Levels of IgA and IgG rose from birth to 18 months, whereas IgM levels did not change significantly. Increases in salivary levels of IgA were associated with introduction of solid foods (P < 0.001), as well as tooth eruption (P < 0.001). Our results indicate that the majority of full-term and preterm infants are orally immunocompetent at birth.

Modified immunogenicity of a mucosally administered antigen

Streptococcus mutans is present in the saliva of most individuals and is modified by salivary components bound to the cells. These saliva-bound S. mutans are swallowed, exposed to high levels of acidity in the stomach, and presented to the common mucosal immune system. Much effort has been directed to identifying the specific S. mutans antigens that the mucosal immune responses are directed against. However, little is known about the host-altered antigenic determinants that the mucosal immune system recognizes. The immunogenicity of gastrically intubated untreated S. mutans cells, cells coated with whole human saliva, cells treated with HCl (pH 2.0), and saliva-coated and acid-treated cells in mice was investigated. Saliva and serum samples were assayed by enzyme linked immunosorbent assay for immunoglobulin A (IgA) and IgG antibodies, respectively, against the untreated or treated S. mutans cells. In general, the levels of salivary IgA and serum IgG antibodies to the antigen against which the mice were immunized were significantly higher (P < or = 0.05). In addition, human saliva and serum samples from 12 subjects were assayed for naturally occurring antibody against the untreated or treated S. mutans cells. In every case, significantly higher reactivity was directed against the saliva-coated and acid-treated cells followed by the saliva-coated S. mutans. These results provide evidence for the altered immunogenicity of swallowed S. mutans in humans by coating native S. mutans antigens with salivary components and/or denaturing surface S. mutans antigens in the acidic environment of the stomach, which would lead to an immune response to modified S. mutans determinants and not to native S. mutans antigens.

Anti-Streptococcus mutans antibodies in saliva of children with different degrees of dental caries

The aim of this study was to evaluate the relationship between the secretory immune system and dental caries. Forty-nine 3-5-year-old children with primary dentition were classified into three groups according to their caries indices: no caries (group I), one or two surfaces with caries lesions (group II) and rampant caries (group III). Lower numbers of mutans streptococci were found in group I in relation to groups II and III. Secretory IgA and anti-S. mutans IgA, IgM and IgG antibody levels were not significantly different among the groups. Western blotting analysis showed that some S. mutans proteins, including the 39, 59, 97 and 150 kDa molecular mass bands, were recognized by almost all the saliva samples. Antibodies against the 185 kDa band, known as antigen I/II, were present in all adults' saliva and in only one child in group III. The absence of antibodies to the 185 kDa band in children's saliva suggest a specific immunologic immaturity. Further prospective studies will be necessary to establish the possible effect of reactivity to this antigen on the S. mutans colonization in this age group.

Antimicrobial function of human saliva--how important is it for oral health?

Human saliva contains a number of physical physicochemical, and chemical agents that protect oral tissues against noxious compounds, in particular those produced by various microorganisms. Among such protective factors, the flushing effect of saliva flow is the most important one, not only because it so effectively removes exogenous and endogenous microorganisms and their products into the gut but also because a steady supply of saliva guarantees continuous presence of both non-immune and immune factors in the mouth. A great number of studies with controversial results have been published regarding various individual agents and their possible association to oral health, particularly to dental caries. It appears that no single chemical agent is far more important than the others. For example, patients with selective IgA deficiency have normal levels of non-immune defense factors and often display a compensatory increase in the other immunoglobulin isotypes. The concerted action of all agents in whole saliva, both saliva- and serum-derived, provides a multifunctional protective network that is collapsed only if salivary flow rate is substantially reduced. In this mixture of defense factors, many show additive or even synergistic interactions against oral pathogens. Increased knowledge of the molecular functions of various agents has made it possible to prepare oral hygiene product that include host-derived antimicrobial agents instead of synthetic agents. Although the clinical efficacy of such products is still unsatisfactory and poorly described, new technologies, for example in the production of specific antibodies against oral pathogens, may considerably improve the antimicrobial power of these products.

Oral microbial ecology and the role of salivary immunoglobulin A

In the oral cavity, indigenous bacteria are often associated with two major oral diseases, caries and periodontal diseases. These diseases seem to appear following an imbalance in the oral resident microbiota, leading to the emergence of potentially pathogenic bacteria. To define the process involved in caries and periodontal diseases, it is necessary to understand the ecology of the oral cavity and to identify the factors responsible for the transition of the oral microbiota from a commensal to a pathogenic relationship with the host. The regulatory forces influencing the oral ecosystem can be divided into three major categories: host related, microbe related, and external factors. Among host factors, secretory immunoglobulin A (SIgA) constitutes the main specific immune defense mechanism in saliva and may play an important role in the homeostasis of the oral microbiota. Naturally occurring SIgA antibodies that are reactive against a variety of indigenous bacteria are detectable in saliva. These antibodies may control the oral microbiota by reducing the adherence of bacteria to the oral mucosa and teeth. It is thought that protection against bacterial etiologic agents of caries and periodontal diseases could be conferred by the induction of SIgA antibodies via the stimulation of the mucosal immune system. However, elucidation of the role of the SIgA immune system in controlling the oral indigenous microbiota is a prerequisite for the development of effective vaccines against these diseases. The role of SIgA antibodies in the acquisition and the regulation of the indigenous microbiota is still controversial. Our review discusses the importance of SIgA among the multiple factors that control the oral microbiota. It describes the oral ecosystems, the principal factors that may control the oral microbiota, a basic knowledge of the secretory immune system, the biological functions of SIgA, and, finally, experiments related to the role of SIgA in oral microbial ecology.

Intrafamilial similarity in immunoblot profiles of salivary immunoglobulin A antibody activity to oral streptococci

Analysis of the salivary immunoglobulin A (IgA) antibody activity to antigens separated from oral streptococci was carried out on 49 individuals in 11 families. The aim of this study were to i) study the human salivary IgA activity within families to antigens separated from reference strains of Streptococcus mutans, Streptococcus sobrinus and Streptococcus parasanguis and ii) to search for potential differences in the salivary IgA activity to the streptococcal antigens several years apart. The immunoblot revealed similarity in saliva IgA response within the families. A majority of the bands, approximately 7 (median) for each extract was found in both child and parent. A few bands (approximately 3) were found in parents but not in children. Only one to two bands were found in children's saliva without a corresponding band in any of the parents. The antibody activity of saliva samples obtained several years apart was essentially unchanged, especially considering the total number of bands. Differences in the relative intensity of the bands could be seen, and a few bands appeared only in some immunoblots for a specific subject. For 3 of 4 children participating in the longitudinal study, more bands against mutans streptococci appeared with age.

Emergence of immune competence in saliva

Saliva contains essentially no IgA at birth. However, secretory immune responses to oral and non-oral microbial antigens emerge early in life. We have investigated the characteristics of these responses in salivas of infants less than 1 month through 4 years of age, using cross-sectional and longitudinal approaches. Antibody specificities (IgA, IgA1, and IgA2) were measured in ELISA and Western blot analysis to antigens of Streptococcus mitis and S. salivarius that colonize during the neonatal period. Antibodies reactive with S. sanguis and mutans streptococci, which colonize later in the infant's life, were also determined. Concurrent investigation of the oral flora of each infant was performed and related to the observed antibody specificities. The secretory nature of the immunoglobulins in these salivas was analyzed immunologically and chromatographically. The primary molecular form of salivary IgA was dimeric in all salivas tested. Both IgA subclasses were found, although a subset of infant salivas initially contained > 90% IgA1. IgM (> 1 microgram/ml) was detected in 58% of 3- to 17-week-old infants. By 2 months of age, salivas from most infants contained IgA antibody reactive with at least two S. mitis components. Many salivas also contained antibody reactive with S. salivarius components. By the end of the first year, most salivas contained IgA1 and IgA2 antibody to S. mitis antigens. Maturation of secretory responses in the second and third year was evidenced by the appearance of increased concentrations and additional specificities of salivary IgA antibodies to S. mitis antigens. Antibody to S. mitis, S. salivarius, and S. sanguis extracellular components was detected only after infection with the respective species.(ABSTRACT TRUNCATED AT 250 WORDS)

Periodontal disease and dental caries in relation to primary IgG subclass and other humoral immunodeficiencies

22 females and 3 males with primary hypogammaglobulinaemia (n = 6) or IgG subclass deficiencies with (n = 3) or without (n = 16) concomitant IgA deficiency were examined for periodontal disease and dental caries. Only 1 patient showed more tooth loss than that found in the normal Swedish population. 1 patient demonstrated advanced periodontal disease. No patient exhibited more severe dental caries than that of comparable normal Swedes. Microbiological samples from periodontal pockets and saliva showed recovery of potential periodontopathic and cariogenic bacteria within normal ranges. This study could not support the notion that immunodeficient subjects exhibit an increased risk of developing periodontal disease or dental caries.

Ontogeny of immunity to oral microbiota in humans

This article reviews the ontogeny of immune systems in the human oral cavity that may influence the colonization, accumulation, or pathogenesis of oral microbiota. The prenatal development of cellular components associated with the secretory immune system reveals that the initial organization of tissue into Peyer's patches can first be detected immunohistologically at 11 weeks gestation. Epithelial cells positive for secretory component and immunocytes positive for IgM can be detected in salivary gland tissue by 19 to 20 weeks and continue to predominate during gestation. After birth, immunocytes containing IgA begin to dominate. Essentially, no IgA can be detected in saliva at birth. However, salivary IgA and IgM often appear soon thereafter, presumably in response to environmental antigenic and mitogenic challenges. Salivary IgA in young infants has molecular characteristics of secretory IgA and becomes the quantitatively predominate Ig in saliva. Both IgA subclasses are present in proportions characteristic of adult pure glandular salivas in many 1- to 2-month-old infants, although the appearance of IgA2 is delayed in some subjects. Many innate, antibody, and cellular immune components are found in maternal colostrum and breast milk. The antibacterial properties of these maternal factors are diverse and can exert multifaceted protective effects on the infant's alimentary tract. The infant apparently can mount mucosal immune responses quite early in life. For example, salivary antibody activity to organisms that originally colonize the gut (e.g., E. coli) or the oral cavity (e.g., S. mitis, S. salivarius) can be detected by 1 to 2 months of age. Most of this antibody activity has characteristics of secretory IgA, although some IgM antibody can also be initially detected. Salivary IgA1 and IgA2 antibody specificities to S. mitis and S. salivarius components increase qualitatively and quantitatively during the first few years of life. Salivary IgA antibody to components of streptococci that require hard surfaces for colonization (e.g., S. sanguis and mutans streptococci) generally appear after tooth eruption. The loss of placentally derived maternal IgG antibody specificities to these microbiota in the circulation is replaced by de novo synthesis, presumably as a result of the teething process. These IgG antibodies can enter the oral cavity in the gingival crevicular fluid and by the process of teething.(ABSTRACT TRUNCATED AT 400 WORDS)

Crevicular IgG antibodies and recovery of locally implanted Streptococcus mutans in humans

This study was undertaken with the aim of examining the effect of highly different IgG antibody activities in gingival crevicular fluid (GCF) on the elimination of a streptomycin-resistant strain of Streptococcus mutans (S. mutans) topically implanted on the tooth. Two groups of people were selected for the study, one with high and one with low specific IgG antibody activity (IgG antibody activity against S. mutans) in GCF. During an experimental period of 15 d the specific IgG antibody activity in GCF in the same individual stayed on a relatively constant level. Between individuals, however, the specific IgG antibody activity varied considerably. The number of indigenous mutans streptococci and the number of implanted bacteria on the same tooth surface were strongly correlated. The implanted S. mutans strain was rapidly eliminated in all subjects. No difference in the elimination of the implanted strain of S. mutans could be demonstrated between the groups of high and low specific IgG antibody activity.

Caries in the preschool child: aetiology

Although a substantial number of preschool children are caries free at 5 years of age, there remain a small proportion with caries who require a considerable amount of effort and time invested in them. Therefore, the multifactorial nature and ramifications of dental caries are considered in turn. The evidence cited is pertinent, especially in relation to our multiracial society and current disease levels for this age group.

Maternal caries incidence and salivary close-contacts with children affect antibody levels to Streptococcus mutans in children

Serum and salivary immunoglobulins and antibodies reactive with Streptococcus mutans were determined in 67 5-8-year-old children. The children of mothers whose caries incidence rates exceeded the median value had significantly more serum IgG antibodies to S. mutans than those with a lower maternal caries activity (p less than 0.05). The children (n = 14) who had been exposed to frequent maternal salivary close-contacts in their first year had significantly higher (p less than 0.05) serum total specific IgG antibodies but significantly lower (p less than 0.01) high-avidity IgG antibodies to S. mutans than the other children (n = 53) with less frequent close-contacts. The maternal caries incidence rates were significantly positively associated with children's dfs/DFS-indices (r = 0.41; p less than 0.001). However, the high maternal caries incidence did not increase the risk of caries in those children whose mothers' saliva contained high amounts of lactobacilli during the first nursing year, when compared with matched children with a low maternal level of lactobacilli. This was possibly due to the fact that the former children had significantly (p less than 0.05) more anti-S. mutans IgG antibodies in their sera than the latter.