The role of salivary antimicrobial peptides in shaping Streptococcus mutans ecology

Abstract

Antimicrobial peptides are among the repertoire of host innate immune defenses. In mucosal immunity, the health-disease balance can be greatly modulated by the interplay between host immune factors and colonized microflora. Microbial ecology within dental plaque is constantly shaped by environmental factors present within the oral cavity. Several antimicrobial peptides are detected in saliva and their bactericidal activities against oral bacteria, including Streptococcus mutans, the primary etiologic agent of dental caries, have been clearly demonstrated. However, the role of these antimicrobial peptides in S .mutans ecology and host caries experience is not welldefined. We hypothesized that various strains of S. mutans possess different inherent susceptibility/resistance profiles to host salivary antimicrobial peptides and that hostspecific quantities of these peptides may influence plaque colonization by particular S. mutans strains. S. mutans strains from subjects with variable caries experience were tested for susceptibility to a panel of antimicrobial peptides, including HNP-1-3, HBD-2-3 and LL-37, revealing that the susceptibilities of S. mutans to these peptides were strain-specific. S. mutans strains from high caries subjects showed greater resistance to these peptides at varying concentrations than those from caries-free subjects. In addition, when combinations of these peptides were tested, they showed either additive or synergistic interaction against S. mutans. Determinations of the salivary levels of these peptides showed that their concentrations were highly variable among subjects with no correlation to host caries experience. However, positive relationships between the salivary concentrations of HNP-encouragement. I am also grateful for kind hospitality and generosity of Dr. Ronald Ettinger and his wife, Sonia, who always provide the warmest support for us, Thai students. Importantly, I would like to thank my mom, dad, sisters, brother and friends in Thailand, including Ann, Oat, Antt and Earth, who have been there for me throughout this long process. I could not have done this without them. Last but not least, I would like to thank the Royal Thai Government Scholarship for providing me the financial support for my graduate study and giving me the opportunity to study here in Iowa.

Expression analysis of CD63 in salivary neutrophils and the increased level of Streptococcus mutans in severe early childhood caries

“…After the sample was collected, it was frozen at -80°C to be analyzed. 10 S. mutans isolation was done by taking saliva sample from preschool children identified either as severe caries (def-t >6) or caries-free performed in the following instructions: biochemical isolation and characterization from S. mutans. Saliva sample then were diluted in brain heart broth (BHI), after incubated for 24 hours, sample was planted on gelatin medium triptone yeast cystein (TYC).…”

Salivary neutrophils isolation of severe early childhood caries patients with flow cytometry analysis using magnetic beads and CD177 marker

“…After collected, the samples were stored at -80° C for analysis. 10 Salivary neutrophils were obtained by asking the subjects to rinse their mouth with 10 mL of sterile 1.5% NaCl solution for 30 seconds, and then expectorated in a sterile glass. This procedure was repeated four times.…”