Mitosis and differentiation in T-cells under cytotoxic action of Echinococcus granulosus hydatid fluid

In the T-cell line, D10, thymidine uptake was used to measure the proportio n of cells in S-phase, and the MTT assay to measure the number of viable ce lls. The effect of Echinococcus granulosus hydatid fluid (HF) on the lympho cytes was assayed in 3-day cultures of the T-cell line, D10, in increasing concentrations of HE Apparent cytotoxic effects of HF were recorded as a lo g-linear decline in S-phase activity, which was reduced by the presence of IL-1, IL-2, or a combination of the two. In the presence of IL-2, however, mitogenic treatment with concanavalin A increased the cytotoxic effect in 3 -day cultures, while in day-2 cultures, HF itself showed mitogenic effect. HF-induced decline in S-phase activity was not matched by a parallel declin e in viable cells, suggesting that the apparent cytotoxicity of HF could re sult from cell-cycle arrest. Depending on its origin, HF enhanced membrane expression of CD25 and CD38 on human peripheral blood lymphoblasts, and dim inished that of CD28. Taken together, these changes suggest that HF can ind uce T-cell mitosis and reduce co-stimulation with subsequent T-cell anergy or apoptosis. (C) 2001 Elsevier Science B.V. All rights reserved.