Expression profile of human defensins and antimicrobial proteins in oral tissues

Antimicrobial peptides and proteins are an important part of the innate host defense. In the present study, the expression profile of three human alpha-defensins, of two human beta-defensins (hBD) and of phospholipase A-2 (PLA-2) and lysozyme was determined by reverse transcription-polymerase chain reaction (RT-PCR) in 56 non-inflamed and 18 inflamed oral tissue samples and primary oral keratinocytes and fibroblasts. The transcripts for hBD-1 and -2 as well as for PLA-2 and lysozyme were found to be widely expressed. In the group of the alpha-defensins, the message for the human neutrophil peptide-1 (HNP-1) was frequently detected, whereas an expression of human Paneth's cell defensin-5 (HD-5) was identified in only a minority of samples. Transcripts for HD-6 were not detectable in any sample. Oral keratinocytes but not fibroblasts contained transcripts for the beta-defensins, suggesting that these defensins are produced in the epithelial compartment. In contrast, mRNA expression of neutrophil-derived HNP-1 and PLA-2 was not observed in any of these cells. These results suggest an important role for hBD-1 and hBD-2 in the innate oral epithelial host defense.