Binding properties of Treponema denticola lipooligosaccharide

BACKGROUND AND OBJECTIVE The cell-surface lipooligosaccharide (LOS) of Treponema denticola possesses several biological properties. The aim of this study was to investigate the binding properties of T. denticola LOS to extracellular matrix (ECM) proteins, mucosal cells, and oral bacteria. DESIGN LOS was isolated from T. denticola and labeled with tritium. Tritium-labeled LOS was placed in ECM protein-, epithelial cell-, fibroblast-, or bacterium-coated wells of a 96-well microplate. Following incubation, unattached LOS was removed by extensive washing, and the amount of bound LOS was determined by measuring the radioactivity in the wells. Peptostreptococcus micros coated with LOS was used to stimulate fibroblasts, and the secretion of interleukin-6 (IL-6) and interleukin-8 (IL-8) by the fibroblasts was determined by ELISA. RESULTS T. denticola LOS had a high affinity for laminin. It also bound to gingival epithelial cells and fibroblasts. Soluble CD14 significantly increased the binding of LOS to fibroblasts. More LOS bound to P. micros than the other oral bacterial species tested. Stimulating fibroblasts with LOS-coated P. micros induced the secretion of IL-6 and IL-8. CONCLUSIONS Our study provided evidence that T. denticola LOS possesses the capacity to bind to ECM proteins, mucosal cells, and oral bacteria. In addition, LOS binding to bacteria may increase their pro-inflammatory potential.