MLR-stimulatory capacity of TN cells generated in the presence of IL-7. TN cells derived from 12-day IL-7–treated FTOC (including 75% to 85% of OX-62⁺ cells; ▪) and control FTOC (including 15% to 25% of OX-62⁺ cells; □) were used at different numbers as stimulators for allogeneic T cells (2 × 10⁵) isolated from lymph nodes. Those were compared with normal thymic DC isolated from rat thymus (▵). After 5 days the cultures were pulsed for 4 hours with BrdU. A specific kit was used to measure BrdU incorporation into newly synthesized DNA. Full details are given in Materials and Methods. Results are the means of the pooled data from two to three independent experiments, each with five cultures per point. Standard deviations represented less than 10% of the mean values.