Salivary Defense Proteins: Their Network and Role in Innate and Acquired Oral Immunity

Abstract

There are numerous defense proteins present in the saliva. Although some of these molecules are present in rather low concentrations, their effects are additive and/or synergistic, resulting in an efficient molecular defense network of the oral cavity. Moreover, local concentrations of these proteins near the mucosal surfaces (mucosal transudate), periodontal sulcus (gingival crevicular fluid) and oral wounds and ulcers (transudate) may be much greater, and in many cases reinforced by immune and/or inflammatory reactions of the oral mucosa. Some defense proteins, like salivary immunoglobulins and salivary chaperokine HSP70/HSPAs (70 kDa heat shock proteins), are involved in both innate and acquired immunity. Cationic peptides and other defense proteins like lysozyme, bactericidal/permeability increasing protein (BPI), BPI-like proteins, PLUNC (palate lung and nasal epithelial clone) proteins, salivary amylase, cystatins, prolin-rich proteins, mucins, peroxidases, statherin and others are primarily responsible for innate immunity. In this paper, this complex system and function of the salivary defense proteins will be reviewed.

Oral Helicobacter pylori: Interactions with host and microbial flora of the oral cavity

“…In addition, some of these compounds also possess immunomodulating activity and the ability of chelating metal ions from the local environment (Fe 3+ , Ni 2+ , Cu 2+ ). 3 Another important component of mucus is the high molecular weight oligomeric glycoproteins, namely mucins. More than 20 mucins covering the epithelial surface of the respiratory, digestive and reproductive tracts have been detected in the human body.…”

“…It is located mainly in the submandibular and sublingual salivary glands. 3,4 Mucins and defense proteins play a crucial role in the formation of acquired pellicle, i.e., a thin layer (0.5-1 μm) of saliva components with the ability to bind to calcium hydroxide. These components have receptors for microbes and, thus, in the surface immune exclusion process, contribute to the immobilization of microorganisms and protection against host tissue invasion.…”

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“…Also, they neutralize the lipopolysaccharides of gram-negative bacteria and exhibit fungicidal activity against several Candida species, Aspergillus fumigatus, some strains of Saccharomyces cerevisiae, and Cryptococcus neoformans [36,37]. Some defense proteins, like chaperones HSP70/HSPAs (70 kDa heat shock proteins), are also involved in both innate and acquired immunity [30]. In addition, saliva contains abundant CD14 amounts from salivary glands in a soluble form, although LPS-binding protein was below detectable levels, suggesting that saliva CD14 is important for the maintenance of oral health [38].…”

“…Lysozyme is a hydrolytic enzyme that cleaves the carbohydrate components of the cell wall peptidoglycan, resulting in cell lysis. This enzyme is active against both gram-negative and gram-positive microorganisms; its targets include Veilonella species and Actinobacillus actinomycetencomitans [30]. Lactoferrin is an iron-binding glycoprotein that links to free iron in the saliva, causing bactericidal or bacteriostatic effects on various microorganisms requiring iron for their survival.…”

“…The microbiota plays a fundamental role on the induction, training and function of the host immune system, the interactions between mucosal surfaces and microbiota accomplishing a key role in host defense, health and disease. fluid), and oral wounds reinforced by immune and/or inflammatory reactions of the oral mucosa are primarily responsible for innate immunity [30]. Lysozyme is a hydrolytic enzyme that cleaves the carbohydrate components of the cell wall peptidoglycan, resulting in cell lysis.…”