T-cell stimulatory capacity of MDCs and PDCs isolated from AML patients.

MDCs and PDCs were sorted from the blood of healthy individuals or leukemic patients and cultured for 3 days in the presence of GM-CSF, IL-4, and CD40L (MDCs) or IL-3 and CD40L (PDCs). (A) Allostimulatory activity of 3-day–cultured MDCs and PDCs was monitored by their ability to induce the proliferation of CD4⁺ naive T cells. The ratio between the proliferative response measured by [³H]thymidine incorporation of 10⁵ T cells induced by 3 × 10³ leukemic MDCs and PDCs and normal MDCs and PDCs is represented. Results are represented as the mean of the ratio obtained from 4 experiments performed with DCs isolated from patients UPN109, UPN156, UPN223, and UPN90. (B) Allostimulatory activity of freshly isolated and 3-day–cultured PDCs. Graded numbers of freshly isolated PDCs from healthy donor (▵) or patient UPN109 (▴), or 3-day–cultured PDCs from healthy donor (○) or patient UPN109 (●), were cocultured with 10⁵ CD4⁺naive T cells for 6 days. CD14⁺ monocytes (purified by magnetic separation using CD14 microbeads; Myltenyi Biotec GmbH, Bergisch Gladbach, Germany) from healthy donor (▪) were prepared and used as control stimulators. Representative data of 3 experiments are shown.