Figure 2.
Tolerant CD4+ T cells suppress IL-2 production by naive CD4+ T cells, and exogenous IL-2 rescues the suppression. (A) Control naive CD4+ T cells (5 × 104), tolerant CD4+ T cells (5 × 104), or the mixture (1:1) was cultured with Mls-1a stimulators (5 × 105). Culture supernatants were harvested on the indicated day, and IL-2 concentration was measured by ELISA. The lower limit of detection was 49 pg/ml. (B) Control naive CD4+ T cells (5 × 104), tolerant CD4+ T cells (5 × 104), or the mixture (1:1) was cultured with Mls-1a stimulators (5 × 105) in the presence of graded concentrations of rIL-2. Each experiment was repeated three times.