EFFECT OF SONICATED MATERIAL FROM FUSOBACTERIUM-NUCLEATUM ON THE FUNCTIONAL-CAPACITY OF ACCESSORY CELLS DERIVED FROM DENTAL-PULP

Fusobacterium nucleatum-derived components were studied for their effe ct on the ability of accessory pulpal cells to induce T-lymphocyte pro liferation. In initial experiments, spleen cells were used to establis h concentration ranges at which testing of the effect of the bacterial components would be suitable. At low concentrations, bacterial substa nces induced a stimulatory effect on the proliferation rate of spleen cells, but not when purified T-lymphocytes were incubated in the prese nce of concanavalin A and pulpal accessory cells. At increasing concen trations, a dose-dependent reduction was observed. Pretreatment with t he bacterial products for 4 h gave a stimulatory effect in the absence of concanavalin A for both spleen cells and T-lymphocytes. Removal of low-molecular-weight components (<3.5 kDa) did not influence the inhi bitory effect, whereas preheating the bacterial substances to 100 degr ees C eliminated the observed inhibition. Findings show that heat-sens itive, high-molecular-weight components of F. nucleatum can evoke a co ncentration-dependent stimulatory or suppressive effect on the prolife ration rate of T-lymphocytes in the presence of accessory cells derive d from the dental pulp.