Fig. 4.
Influence of IL-2 family cytokines on Treg suppressive function. Purified Tregs were activated with immobilized anti-CD3 and the indicated cytokines for 3 days, washed, and used in an inhibition assay together with TCR-II T cells at the indicated ratio. Cultures were supplemented with syngeneic splenocytes and antigen as described in Materials and Methods. Proliferation was determined after 72 h 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. Treg:Eff, Treg:effector ratio.