Quantitation of IgA in Human Whole Saliva

Serum and salivary anti-capsular antibodies in infants and children immunized with the heptavalent pneumococcal conjugate vaccine

AIM

To study the ability of seven-valent experimental pneumococcal polysaccharide CRM197 protein conjugate vaccine (PncCRM) to induce antibodies in serum and saliva of infants.

METHODS

Sixty Finnish infants received Pnc-CRM vaccine at 2, 4 and 6 months of age and were boosted with PncCRM (n = 30) or pneumococcal polysaccharide (PncPS) (n = 29) vaccine at the age of 15 months. Serum IgG antibody concentrations to vaccine serotypes 4, 6B, 9V, 14, 18C, 19F and 23F were measured by enzyme immunoassay at 2, 4, 6, 7, 15, 16 and 24 months of age. Salivary IgA, IgG and secretory Ig antibody titers at 7 and 16 months of ages were analyzed by enzyme immunoassay against the same serotypes, except 23F.

RESULTS

PncCRM induced systemic immune responses and immunologic memory. At 7 months of age 69 to 100% of children, depending on the serotype, had serum IgG antibody concentrations exceeding the value of 1.0 microg/ml. At 15 months the titers were still higher than before the vaccinations. Booster doses of either PncPS or PncCRM induced an increase in antibody concentrations. The titers were still elevated at 24 months of age. Salivary IgA and IgG antibodies were found rarely at 7 months of age, but in up to 80% of samples taken at 16 months of age, depending on the serotype and nature of the booster vaccine. Salivary IgG correlated with IgG in serum, supporting the theory that salivary IgG is derived from serum. Salivary IgA and secretory Ig correlated positively, which indicates that IgA was locally produced.

CONCLUSIONS

PncCRM induces both systemic and mucosal immune responses in infants.

Antibodies to pneumolysin and pneumococcal capsular polysaccharides in middle ear fluid of children with acute otitis media

Antibodies to pneumococcal pneumolysin and capsular polysaccharides were measured by enzyme immunoassay in 169 acute phase middle ear fluid samples of 116 children with acute otitis media. Antibodies to pneumococcal pneumolysin were detected in 84% and to capsular polysaccharides in 50% of the MEF samples. The Ig class detected most often was IgA to both types of pneumococcal antigens, and it was present in MEF even with non-detectable levels of serum IgA of the same specificity. 59% of the MEF samples positive for IgA to pneumolysin were also positive for secretory component of the same specificity, and 53% of IgA to capsular polysaccharide pool (containing serotypes 6B, 14, 19F, and 23F), respectively. This suggests both leakage of specific IgA from serum to the middle ear and local production of it. In contrast, specific IgG was detected in MEF only with concomitant IgG in serum. Antibodies to pneumolysin occurred in no relation to bacterial findings in MEF. On the contrary, IgG class antibodies to capsular polysaccharides, most likely serum-derived, were detected less often in MEF samples positive for pneumococcus than for other bacteria.

Nasopharyngeal antibodies to pneumococcal pneumolysin in children with acute otitis media

Pneumolysin, an intracellular protein toxin of all clinically relevant pneumococcal serotypes, is released in vivo during the autolysis of pneumococci and is believed to pave the way for intact pneumococci to invade and cause disease. Therefore, antibodies to pneumolysin should prevent its destructive function. We measured antibodies to pneumococcal pneumolysin in acute- and convalescent-phase nasopharyngeal aspirate samples of 120 children (median age, 2.5 years) with acute otitis media by enzyme immunoassay. Nasopharyngeal immunoglobulin M (IgM) and IgG class antibodies to pneumolysin were rarely detectable, whereas IgA class antibody was detected often, occurred independently of serum IgA antibody in serum, and correlated with the presence of the secretory component in pneumococcal antibody, indicating local production of IgA antibodies. Nasopharyngeal IgA antibody to pneumolysin was detected in 93% of the children already in the acute phase of otitis. Twenty percent of the children developed at least a threefold rise in the pneumolysin-specific IgA antibody concentration by the convalescent phase of otitis, with the youngest at 6 months of age, regardless of the pneumococcal findings in the nasopharynx or middle ear fluid. We suggest that nasopharyngeal IgA antibody to pneumolysin can be produced early in life by pneumococcal colonization.

Salivary immunoglobulins, lysozyme, pH, and microbial counts in children receiving anti-neoplastic therapy

Salivary immunoglobulins, lysozyme, pH, and microbial counts were determined in 55 children with cancer diseases (37 cured subjects and 18 acute ones) and 103 healthy subjects. 5-10 ml unstimulated whole saliva was collected and pH, immunoglobulins and lysozyme were measured. Chairside dip-slide cultivations were used for microbiologic cultures. Reduced salivary pH and an increased amount of lysozyme were found in the saliva of those children who had been cured of their cancer diseases, but ongoing cancer disease or the treatment provided for it reduced pH and increased the amounts of lysozyme, lactobacillus, Streptococcus mutans and some immunoglobulins. These findings suggest that children with childhood cancer may be more susceptible to dental diseases than healthy ones.

Salivary immunoglobulin concentrations in predentate and edentulous mouths

The concentrations of IgA, IgG and IgM in whole saliva of predentate babies, dentate adults, and edentulous old people, and the salivary IgG concentration of dentate old people, were determined using a solid phase radioimmunoassay. A highly significant difference in IgG concentrations was found between toothless and dentate people. The average IgG concentration in the saliva of edentulous old people was 5.2 mg/1, which was about 20% of that of dentate old people. The salivary IgG content of babies was only 1.7 mg/1, which was in concordance with the low postnatal serum IgG values. The salivary IgA level in this age group was also low. The edentulous old people tended to have decreased IgM values, and the predentate babies tended to have increased IgM values compared with the dentate adults.

Immunochemical quantitation of alpha-amylase and secretory IgA in parotid saliva from people of various ages

The alpha-amylase (128 subjects) and secretory IgA (118 subjects) concentration in stimulated parotid saliva of healthy individuals aged 23-84 years, was determined. They were divided into three age groups: I, 23-39; II, 40-59; and III, 60-84 years old. The concentrations (microgram/ml) of alpha-amylase for group I = 803.6; II = 648.0; and III = 652.4; the concentrations for secretory IgA for group I = 96.2; II = 101.8; and III = 97.7. The Kruskal-Wallis test revealed no significant differences between groups for alpha-amylase or secretory IgA.

The concentration of salivary IgA in whole and parotid saliva and the effect of stimulation

The concentration of salivary IgA was measured in 24 healthy volunteers. The resting salivary IgA (n = 19) was 14.5 +/- 7.5 mg/dl in parotid saliva and 6.5 +/- 3.6 mg/dl in whole saliva. After stimulation (n = 5), parotid IgA decreased to 6.8 +/- 5.0 mg/dl and whole-saliva IgA to 3.1 +/- 2.22 mg/dl. Freezing caused a diversified decrease in IgA concentration.

Salivary immunoglobulins in patients with juvenile periodontitis and their healthy siblings

The concentrations of the salivary immunoglobulins IgA, IgG and IgM were determined with a solid phase radioimmunoassay in the unstimulated whole saliva of 21 patients with juvenile periodontitis (JP), their 27 healthy siblings and 17 healthy age-matched controls. In the JP group the concentrations of IgA were increased, averaging 188 +/- 32.5 (SE) mg/L as compared with the mean of 139 +/- 21.2 mg/L in their healthy siblings and 130 +/- 24.5 mg/L in the controls. An elevation was found in the amount of IgG in the JP patients 45.6 +/- 12.5 mg/L as compared with 18.1 +/- 5.9 mg/L in the siblings and 21.0 +/- 5.6 mg/L in the controls. The mean IgM was 22.5 +/- 5.4 mg/L in the JP group, 13.3 +/- 2.9 mg/L in the siblings and 8.7 +/- 1.6 mg/L in the controls, indicating an increase of IgM in the JP group and the siblings. A significant difference was found in the mean IgM values in the juvenile periodontitis group when compared to the control group. (0.02 greater than P greater than 0.01).

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.