Lysozyme and Lactoperoxidase Inhibit the Adherence of Streptococcus mutans NCTC 10449 (Serotype c) to Saliva-Treated Hydroxyapatite in vitro

Abstract

Lysozyme, lactoperoxidase and salivary peroxidase inhibit the metabolism and growth of mutans streptococci, but any possible effects on the adherence of these bacteria are unknown. In this study the effects of lysozyme and lactoperoxidase on the adhesion of ³H-labelled Streptococcus mutans (NCTC 10449, serotype c strain) to saliva-coated hydroxyapatite were studied at pH 5.0 and 7.0. Human whole saliva was either lysozyme-depleted and centrifuged, or sterilized and dialysed to achieve no detectable lysozyme and peroxidase activities; this modified saliva was used to form experimental pellicles. The incorporation of lysozyme (50–200 μg/ml) to the pellicle caused a significant (p < 0.01) reduction in the adherence of S. mutans without any loss of bacterial viability. Pretreatment of either saliva-coated apatite or S. mutans cells with lysozyme did not change the results but lysozyme bound more readily to bacteria than to the experimental pellicles. Also, lactoperoxidase (10–200 μg/ml) reduced significantly (p < 0.001) the adherence of S. mutans but, in contrast to lysozyme, in a dose-dependent way. The strongest inhibition of adhesion was found when both saliva-coated apatite and bacteria were pretreated with lactoperoxidase. This enzyme bound to experimental pellicles in preference to streptococci. A non-specific protein control, albumin, did not block the inhibition by lysozyme or lactoperoxidase. The inhibition of adherence of a serotype c strain of S. mutans to saliva-coated hydroxyapatite is a novel antibacterial mechanism for both lysozyme and lactoperoxidase.

Passive Immunization with Bovine Milk Containing Antibodies to a Cell Surface Protein Antigen-Glucosyltransferase Fusion Protein Protects Rats against Dental Caries

“…In the group that received nonimmune milk, the recovery of S. mutans at the end of the experiment was about three times higher than that in the control group, although the caries score of the nonimmunemilk group was approximately the same as that of the control group. Bovine milk has several components which possess cariostatic properties, such as caseins, immunoglobulins, lactoferrin, lactoperoxidase, and lysozyme (12,18,21,27,28). The finding that caries development in the nonimmune-milk group was suppressed might be ascribed to the effects of such milk components.…”

Inhibitory Effect of Bovine Milk Lactoferrin on the Interaction between a Streptococcal Surface Protein Antigen and Human Salivary Agglutinin

“…Bovine milk contains several protein components, including caseins, immunoglobulins, lactalbumin, lactoferrin, lactoglobulin, lactoperoxidase, and lysozyme (14). Casein and lactoperoxidase have been reported to inhibit the adherence of S. mutans to saliva-coated hydroxyapatite (15,16). -Casein reduces the glucosyltransferase activity of S. mutans, which in turn reduces glucan formation (17), and lactoferrin has a bactericidal effect on S. mutans (18).…”

Short Term Comparative Evaluation of Antimicrobial Efficacy of Tooth Paste Containing Lactoferrin, Lysozyme, Lactoperoxidase in Children with Severe Early Childhood Caries: A Clinical Study

“…This may be explained by several reasons, e.g., various salivary agents interact with each other in a complicated way and also inadequate immune defence (usually IgA deficiency) can be compensated by an enhanced non-immunoglobulin activity or by compensatory IgM response [8,10].…”

“…A great number of studies with controversial results have been published regarding various individual agents and their possible association to oral health particularly to dental caries [8][9][10][11].…”