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.