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Objectives: The objective of this study is to evaluate the importance of human lactoferrin (hLF) in an experimental caries induced by Streptococcus mutans in a lactoferrin-knockout (LFKO(-/-)) mouse model compared with C576J/BL wild-type (WT) mice., Materials and Methods: The WT and LFKO(-/-) mice were infected with S. mutans (1 × 10(8) cells) and/or sham infection. Furthermore, the effect of hLF administration was evaluated in LFKO(-/-) mice infected with S. mutans. Mice were assessed for colonization, salivary pH, and caries development., Results: The results showed that the lactoferrin-knockout infected (LFKO(-/-) I) mice had significantly higher colonization with S. mutans (P = 0.02), lower salivary pH (P = 0.01), and more carious lesions (P = 0.01) when compared to wild-type infected (WTI) mice. In addition, the administration of hLF did not show any evidence of S. mutans colonization as well as carious lesions (P = 0.001) in LFKO(-/-) I mice when compared to untreated LFKO(-/-) I mice., Conclusion: These results show that endogenous LF protects against S. mutans-induced caries and that exogenous hLF can exert a protective effect against caries development., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Streptococcus mutans is prominently linked to dental caries. Saliva's influence on caries is incompletely understood. Our goal was to identify a salivary protein with anti-S. mutans activity, characterize its genotype, and determine genotypic variants associated with S. mutans activity and reduced caries. An S. mutans affinity column was used to isolate active moieties from saliva obtained from a subject with minimal caries. The bound and eluted protein was identified as lactotransferrin (LTF) by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) analysis and confirmed by Western blotting with LTF antibody. A single nucleotide polymorphism (SNP) that produced a shift from arginine (R) to lysine (K) at amino acid position 47 in the LTF antimicrobial region (rs: 1126478) killed S. mutans in vitro. Saliva from a subject with moderate caries and with the LTF "wild-type" R form at position 47 had no such activity. A pilot genetic study (n = 30) showed that KK subjects were more likely to have anti-S. mutans activity than RR subjects (P = 0.001; relative risk = 3.6; 95% confidence interval [95% CI] = 1.5 to 11.13). Pretreatment of KK saliva with antibody to LTF reduced S. mutans killing in a dose-dependent manner (P = 0.02). KK subjects were less likely to have caries (P = 0.02). A synthetic 11-mer LTF/K peptide killed S. mutans and other caries-related bacteria, while the LTF/R peptide had no effect (P = 0.01). Our results provide functional evidence that the LTF/K variant results in both anti-S. mutans activity and reduced decay. We suggest that the LTF/K variant can influence oral microbial ecology in general and caries-provoking microbes specifically.

The oral cavity harbors different taxonomic groups, the evolutionary coexistence of which develops the oral ecosystem. These resident microorganisms can alter the balance between the physiologic and pathologic conditions that affect the host, both locally and systemically. This highly sophisticated nature of the oral cavity poses a significant therapeutic challenge. Numerous human and animal studies have been conducted to potentiate the efficacy and competence of current treatments of pathologic conditions as well as to develop novel therapeutic modalities. One of these studies is the use of the potent antimicrobial agent lactoferrin (LF), which was originally derived from the host immune system. LF is an 80‐kDa glycoprotein that has a free iron sequestration mechanism with evident antimicrobial, anti‐tumor, and immunomodulatory properties. A wide range of active peptides have been isolated from the N‐terminal region of LF, which possess antimicrobial activities. In this review, we discuss the role of LF and LF‐derived peptides under a heterogeneous group of oral and maxillofacial conditions, including bacterial, fungal, viral infections; head and neck cancers; xerostomia; and implantology‐bone‐related manifestations. [ABSTRACT FROM AUTHOR]