Figure 5.

Immunosuppression exerted by CD4⁺CD25⁺ T cells in peripheral blood from children tolerant against cow's milk is partly cell contact dependent. CD4⁺CD25⁺ T cells and CD4⁺CD25⁻ T cells were FACS^® sorted and cultured in transwell plates. In some wells, the CD4⁺CD25⁺ T cells were cultured in the upper chamber and the CD4⁺CD25⁻ T cells in the lower chamber, whereas in other plates both subsets were cultured in the lower chambers. Additional controls consisted of CD4⁺CD25⁻ T cells cultured both in the upper and the lower wells as indicated at the bottom of the figure. Stimulation was performed with anti-CD3/CD28 beads for 48 h. The proliferative activity of CD4⁺CD25⁻ was tested by addition of radioactive thymidine (³H-Tdr), and the cells were harvested 12 h later. Incorporation of ³H-Tdr was determined in a β-counter. Note that individual subjects are indicated by separate symbols, and that the y axis is broken. Student's t test was used for statistical analysis.