Antimicrobial Factors in Saliva: Ontogeny and Relation to Oral Health

Abstract

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.

Constitutive Expression of a Bacterial Pattern Recognition Receptor, CD14, in Human Salivary Glands and Secretion as a Soluble Form in Saliva

“…1A). Human submandibular and sublingual glands are mixed glands of serous and mucous cells (10,15,28), and CD14 protein was present only in serous cells and not in mucous cells of tissues from the submandibular gland as determined by immunohistochemistry (Fig. 1C).…”

“…The average daily flow of whole saliva amounts to 1 to 1.5 liters, and it has been suggested that another important protective factor is a constant flow of saliva from the mouth into the intestine (28). Therefore, we speculated that a more specific component responsible for systemic innate immunity acting against bacteria might be secreted from salivary glands into saliva.…”

Does Variability in Salivary Protein Concentrations Influence Oral Microbial Ecology and Oral Health?

“…This can lead to substantial underestimation of peroxidase activity in persons with large amounts of salivary thiocyanate. Assays which eliminate this problem have been devised (Mansson-Rahemtulla et al, 1986), and they are now in common use (Tenovuo et al, 1987;Grahn et al, 1988;Rudney, 1989;Rudney et al, 1991). However, peroxidase activities measured in recent studies may not be fully comparable with those found in earlier studies.…”

“…Evidence for change is strongest for slgA in children. The secretory immune response takes several years to develop, and slgA levels are lower in infants and young children (EverharUUl., 1982;Alaluusua, 1983;Tenovuo et al, 1986aTenovuo et al, , 1987Smith et al, 1987;Gleeson et al, 1991). No such differences are apparent for salivary antimicrobial proteins (Tenovuo et al, 1986a(Tenovuo et al, , 1987.…”

“…Functional measures include bacterial aggregation, promotion of adherence to hydroxyapatite, growth inhibition or enzyme inhibition, and cell-killing (Tenovuo et al, 1987). Each property may be mediated by multiple proteins (Scannapieco, 1994), and each one varies among human subjects (Olson, 1976;Malamud et al, 1981;Koop et al, 1989;Lenander-Lumikari et al, 1992b).…”