Enhancing CCL28 expression through the gene transfer to salivary glands for controlling cariogenic microbe

The chemokine CCL28 participates in direct antimicrobial activities as well as homing of certain types of lymphocytes. The present study was conducted to harness these properties of the chemokine for the prevention of dental caries. The gene encoding CCL28 was transferred to salivary glands to enhance the production of this chemokine locally. First, a recombinant eukaryotic plasmid expressing CCL28 was constructed. Then, the CCL28 protein from 293 cells transfected with the recombinant plasmid was verified to inhibit the caries pathogen Streptococcus mutans (S. mutans) in a biofilm. Finally, the recombinant plasmid was retrogradely administered to the parotid glands of rats through the secretory ducts. The successful transfer of the gene encoding CCL28 to rat parotid acinar cells was confirmed by immunofluorescence and real-time PCR. Increases in both CCL28 and secretory IgA (SIgA) in the rat saliva were tested by ELISA. It was revealed that the CCL28 protein obtained from the study was able to strongly inhibit S. mutans living in biofilm in vitro. The delivery of the recombinant plasmid to the rat parotid glands was able to induce high levels of CCL28 and SIgA in saliva, and the increased levels of CCL28 and SIgA in saliva were maintained for 2 weeks. Notably, the dental plaque from the rats treated with the delivery of the recombinant plasmid in the study harbored significantly less S. mutans. These data indicated that the present strategy may hold hope for the effective prevention of dental caries.