Abstract
It is known that activated T cells show the elevation of telomerase activity and the expression of Fas ligand (FasL). In this study, we investigated the inhibitory effects of pooled human immunoglobulin (PHIG) and dexamethazone (DEX) on peripheral blood mononuclear cells stimulated with streptococcus pyrogenic exotoxin-A (SPE-A), known a bacterial superantigen, through measuring the telomerase activity of the cells and soluble FasL concentration in the culture supernatants. When PHIG was added simultaneously with SPE-A in vitro, both the telomerase activity and soluble FasL concentration were suppressed significantly. But no inhibitory effect was observed when the addition of PHIG was postponed over 12 hr after SPE-A stimulation. On the other hand, telomerase activity was not significantly inhibited by the addition of DEX, but sFasL concentration was suppressed by the addition of DEX until 48 hr after SPE-A stimulation. It was suggested that the clinical effect of PHIG or DEX might be mediated by the inhibition of telomerase activity and Fas-FasL systems to such diseases as induced by excessive immune reactions.
