Fig. 5.
Inhibitory activity of Treg in the presence of IL-2 family cytokines. Purified Tregs were incubated with Th cells at the indicated ratios, together with anti-CD3, APC, and the indicated cytokines. Proliferation was determined by pulsing the cultures with 3H-thymidine for the final 18 h. Statistical significance was tested using a Student’s t-test by comparing the cytokine-stimulated culture with the same population of untreated cells: ***, P < 0.001; **, P < 0.01; *, P < 0.05. The mean ± sd of triplicates of one of three similar experiments is shown.