Objectives: Human β-defensins (hBDs) are a group of small, broad-spectrum cationic antimicrobial peptides. Our recent studies showed that the expression levels and pattern of hBDs were associated with periodontal conditions. The present study aimed to determine the effect of P. gingivalis LPS on the mRNA expression of hBDs as well as pattern recognition receptors and related adaptive molecules in reconstituted human gingival epithelia (RHGE) model. Methods: In the dose-dependant study, RHGE were treated with E. coli 055:B5 LPS or P. gingivalis LPS at various concentrations (1 ng/ml - 10 µg/ml) for 24 hours. While in the time-dependant study, RHGE were treated with 10 ng/ml of E. coli LPS or 10 µg/ml of P. gingivalis LPS for 2, 6, 12, 18, 24, 36, 48, 72 and 96 hours, respectively. The mRNA expression of hBD-1, 2, and 3, CD14, LBP, TLR-2 and -4, MD-2 and MyD88 was detected by RT-PCR. Results: hBD-1, 2, and 3 mRNAs were basally expressed by RHGE. Overall, P. gingivalis LPS (10 µg/ml) markedly enhanced the expression of hBDs at 24 hours with a concurrent expression of TLR-2; whereas E. coli LPS (1 or 10 ng/ml) slightly upregulated the message with a concurrent expression of TLR-4. P. gingivalis LPS enhanced expression of hBD-2 and 3 mRNA was observed at 2 hours. The expression of CD14, MD-2 and MyD88 was independent of the stimulation of P. gingivalis or E. coli LPS. Conclusions: P. gingivalis LPS may enhance the in vitro expression of hBDs 1-3 mRNAs in the reconstituted human gingival epithelia, which might be associated with TLR-2 signaling pathway. Supported by Hong Kong Research Grants Council (RGC HKU 7310/00M).