Aggregation and Adherence of Streptococcus sanguis : Role of Human Salivary Immunoglobulin A

Abstract

Fourteen freshly isolated strains of Streptococcus sanguis were obtained from the dental plaque of five healthy adults. Whole saliva was collected concomitant with the plaque isolates from the five subjects, and a second whole saliva sample was collected 10 weeks later. All possible combinations of the first five saliva samples, the second five saliva samples, and 14 strains of bacteria were tested for aggregation. Of the 140 combinations examined, 108 of 140 (77%) of the strains aggregated with the first saliva samples and 95 of 140 (68%) aggregated with the second saliva samples. Overall, 72% of the strains aggregated with both the first and second saliva samples. Removal of immunoglobulin A (IgA) from these same salivas resulted in 38 of 108 (35%) of the aggregates decreasing in intensity with the first saliva samples and 27 of 95 (29%) of the aggregates decreasing in intensity with the second saliva samples. No aggregates increased in intensity with saliva samples when IgA had been removed. Removal of IgA from saliva also resulted in a mean decrease of 46% in adherence of S. sanguis to hydroxyapatite coated with the IgA-deficient saliva. Several strains of S. sanguis were shown to aggregate strongly with human salivary and colostral IgA. In addition, S. sanguis strain S7 showed a 31% stimulation of adherence to hydroxyapatite precoated with human salivary IgA over the uncoated controls. Stepwise removal of IgA from saliva resulted in a decrease in aggregation intensity from strong (4+) to weak (1+ to 2+). Similarly, the adherence of S. sanguis to hydroxyapatite coated with these saliva samples decreased linearly as the salivary IgA was depleted. Alternatively, the addition of a small quantity of salivary IgA (20 μg/ml) to progressively diluted saliva maintained a high level of adherence and strong aggregation until the saliva dilutions reached between 1:8 in the adherence experiments and 1:32 for the aggregations. These data indicate that salivary IgA may play an important role in the microbial ecology of human dental plaque formation.

Immunohistochemical study of secretory IGA in the human male reproductive tract

“…Secretory IgA antibodies are ideally 'suited to protect the genitourinary system against ascending infections. Several studies indicate that sIgA may interfere with the process of specific interaction involving adhesins on the microbial surface complementary to host surface receptor (Liljemark et al, 1979;Magnusson et al, 1979;Hanson et al, 1983;Abraham & Beachey, 1985;Kilian et al, 1988;Underdown & Mestecky, 1994).…”

Effects of the common cold and intranasal fluticasone propionate treatment on mucosal host defense assessed by human saliva

“…Although the common cold was followed by a significantly enhanced mucosal IgA response, it is not clear whether this effect is clinically important. IgA is one of the major factors eliminating (eg, by aggregation) bacteria and viruses from mucosal surfaces, 23,24 and this effect is therefore likely to be important in vivo. 4,5 However, further studies of the actual microbial changes are needed to elucidate the real biologic significance of our observations.…”

A possible role for lysozyme in determining acute exacerbation in chronic bronchitis

“…Little, however, is known of the presence or function of aggregating agents in controlling colonization of the respiratory tract in patients with chronic lung disease [43.44]. Other models have identified secretory IgA antibody [45] and high inolecular weight glycoproteins [9.46-49] as important aggregants. In this study, however, the lack of correlation between NTHl-specific antibody and aggregation, and calcium-independent aggregation suggests that these factors may not be responsible for the observed differences in salivary aggregating activity.…”