Exogenous LL-37 but Not Homogenates of Desquamated Oral Epithelial Cells Shows Activity Against

Objective: The antimicrobial peptide hCAP18/LL-37 is detected in desquamated epithelial cells of human whole saliva, but the functional importance of this pool of hCAP18/LL-37 is not understood. Here, we assess the impact of homogenates of desquamated oral epithelial cells and exogenous, synthetic LL-37 on two oral bacteria: and .

Material And Methods: Desquamated epithelial cells of unstimulated whole saliva were isolated and cellular and extracellular levels of hCAP18/LL-37 analyzed by ELISA. Bacterial viability was determined by BacLight Live/Dead staining and confocal laser scanning microscopy.

Results: Desquamated oral epithelial cells harboured hCAP18/LL-37, and they spontaneously released/leaked the peptide to their medium. Exogenous, synthetic LL-37 showed cytotoxic activity against but not , suggesting that LL-37 acts differentially on these two types of oral bacteria. Homogenates of desquamated oral epithelial cells had no effect on viability. Treatment with exogenous, synthetic LL-37 (8 and 10 μM) reduced viability, whereas lower concentrations (0.1 and 1 µM) of the peptide lacked effect.

Conclusions: Desquamated oral epithelial cells contain hCAP18/LL-37, but their cellular levels of hCAP18/LL-37 are too low to affect viability, whereas exogenous, synthetic LL-37 has a strong effect on these bacteria.