Immunoglobulins and antibodies in plaque fluid and saliva in two populations with contrasting levels of caries

Antimicrobial factors in saliva: ontogeny and relation to oral health

Antimicrobial agents (antibody and non-antibody) present in human saliva protect oral tissues by a variety of mechanisms, such as prevention of bacterial adhesion, agglutination of micro-organisms, and inhibition of multiplication and metabolism. However, studies in which the concentrations of various salivary antimicrobial agents have been correlated to the presence and severity of oral diseases--of dental caries, in particular--have produced controversial data, and it seems evident, also on the basis of the present study, that no single salivary antimicrobial factor (except flow rate) affects oral health to a significant degree. In the present study, we report the levels of some selected salivary antimicrobial agents in predentate and dentate human infants, with a comparison to the levels found in young adults' saliva. Salivary lysozyme, peroxidase, and hypothiocyanite concentrations were already at the adult level at the time when the primary teeth erupt, whereas immunoglobulin (IgA, IgG, and IgM), lactoferrin, myeloperoxidase, and thiocyanate concentrations were significantly lower in children than in adults. Dentate children had more IgG, thiocyanate, and protein in whole saliva than did predentate children.

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

Salivary IgA-antibody titres against different streptococcal antigens were measured in 64 mothers and their first-born children. Their presence and the level of Streptococcus mutans had been monitored for several years. The children had carried this bacterium for various lengths of time and now had varying numbers of salivary Strep. mutans. The subjects had participated in a longitudinal study completed one and a half years before, concerning prevention of early colonization of the child's mouth by Strep. mutans through measures undertaken by the mother. Whole-saliva samples were collected from all subjects and analysed by ELISA techniques for total IgA, and for IgA antibodies to whole cells of Strep. mutans serotype c and d, whole cells of Strep. sanguis, purified polysaccharide and protein antigens of Strep. mutans serotype c and d; a pool of Escherichia coli antigens was used as a control. No significant differences were found in the level of any of the specific IgA antibodies in children with different levels of indigenous Strep. mutans. A tendency to higher IgA antibody activity was found in children who had levels of Strep. mutans first detectable after three years of age and who had carried the bacterium for six months or less. The IgA antibody activity to Strep. mutans specific serotype c antigen and to whole cells of Strep. mutans serotype c (JC 2) was significantly higher in children with no caries experience when compared to children with more than two df-surfaces. This study offers no clear evidence for a protective role of salivary IgA antibodies against Strep. mutans colonization.

Correlations between human salivary levels of lysozyme, lactoferrin, salivary peroxidase and secretory immunoglobulin A with different stimulatory states and over time

Within-subject correlations for the levels of these salivary proteins were determined in unstimulated and stimulated parotid saliva collected from 8 subjects and for stimulated parotid saliva collected from the same subjects once a week for a 4-week period. Initial correlations between unstimulated and stimulated samples were high and statistically significant (p less than 0.05) for all four proteins. When data were adjusted for variation attributable to flow rate and total protein, some correlations remained the same and those for lysozyme, lactoferrin and salivary peroxidase increased. However, the correlation for secretory immunoglobulin A decreased to a point where it was no longer statistically significant. In the weekly comparison, within-subject correlations across weeks were significant (p less than or equal to 0.05) for lysozyme, lactoferrin and salivary peroxidase, but not for immunoglobulin A. After adjustment for flow rate and total protein, the pattern of correlation was unchanged. Thus the relative rankings of subjects for levels of lysozyme, lactoferrin or salivary peroxidase may be consistent across stimulatory states, even though absolute concentrations may change; levels of these proteins in stimulated parotid saliva may be maintained over time. Secretory immunoglobulin A appears to be more subject to short-term variation.

Longitudinal study of salivary IgA in children from 1 to 4 years old with reference to dental caries

The concentration of salivary IgA was measured and clinical examinations performed annually in 39 children over a period of 36 months. The age of the children ranged from 1 to 4 yr during the observation period. The geometric mean value of salivary IgA increased rapidly between the age of 1 and 2, from 0.021 g/l (log mean - 1.68 +/- 0.33) to 0.052 g/l (log mean - 1.28 +/- 0.24). After this age the mean level of salivary IgA remained fairly constant during the observation period. When the study population was divided into two groups: the caries-free group and the caries-susceptible group, it was found that in the caries-free group the mean salivary IgA value increased rapidly during the second year of life, then more slowly after the age of 2. In the caries-susceptible group the increase in the mean value between the ages of 1 and 2 was marked and at the age of 2 the values were significantly higher compared to those of the caries-free group. The concentrations did not, however, remain high, but fell to lower level and at the age of 4 there was a marked overlap in the values of the groups.

Protein components in saliva and plaque fluid from irradiated primates

Irradiation of the major salivary glands of monkeys (Macaca mulatta) fed cariogenic diets leads to caries clinically indistinguishable from radiation caries in man. This study compares the organic composition of individual samples of plaque fluid and saliva from irradiated and control monkeys receiving the same cariogenic diet. Plaque and saliva were collected from fasting, tranquillised animals. Four irradiated animals were sampled repeatedly as were non-irradiated controls. Total protein, albumin, immunoglobulins A, G, and M, and the third component of complement (C'3) were quantitated in plaque fluid and whole saliva. Salivary amylase and peroxidase activities were also determined. Plaque fluid and saliva samples were also subjected to polyacrylamide gel electrophoresis. The total viable anaerobic count and numbers of Streptococcus mutans were determined in samples of plaque. The results suggest that the major effect of irradiation leading to increased numbers of S. mutans and caries susceptibility is in the amount, and not the composition, of the saliva produced by the residual gland tissue. The scanty flow of saliva may reduce the effectiveness of cleansing, buffering and lubrication mechanisms as well as resulting in a marked reduction in the total amount of specific and non-specific immune factors entering the mouth.