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.