Abstract:

Objective · To isolate lipopolysaccharide (LPS) and capsular polysaccharide (CPS) from Porphyromonas gingivalis (Pg) and analyze their ability to induce THP-1 cells to secrete interleukin 8 (IL-8) in vitro. Methods · LPS and CPS were isolated from the polysaccharides by gel filtration chromatography, which had already been extracted from Pg ATCC33277 and SJD4. The isolated LPS and CPS from different strains were used to stimulate THP-1 cells in different doses and for different periods. The level of IL-8 in the cell culture suspension was measured by ELISA. Results · LPS and CPS were successfully separated from the polysaccharides in Pg ATCC33277 and SJD4. The relative molecular masses of LPS and CPS were 20 000–50 000 and 150 000–500 000, respectively. LPS and CPS could induce THP-1 cells to produce IL-8 in vitro in a time- and dose-dependent manner. The effect of LPS from ATCC33277 on secretion of IL-8 was greater than that of CPS with the dose of 0.1 μg/mL (P<0.05). However, the difference could only be found at 24 h in SJD4, and the effect of CPS was greater (P<0.05). Conclusion · As a component of polysaccharides extracted from Pg, CPS can induce THP-1 cells to secrete IL-8 in vitro in a time- and dose-dependent manner.

Key words: Porphyromonas gingivalis, lipopolyssacharide, capsular polyssacharide, THP-1 cell, IL-8