Fig. 1.

Expansion of lymphocyte subsets after stimulation with IL-2 or IL-2/mAb complexes. (A) Sorted CFSE-labeled Thy1.1⁺ MP CD8⁺ cells were transferred to WT recipients, followed by daily injections of PBS, titrated amounts of IL-2, IL-2 plus anti-IL-2 mAb MAB602 (IL-2/mAb_CD122), and IL-2 plus anti-IL-2 mAb 5344 (IL-2/mAb_CD25) for 5 d. On day 6, spleen cells were analyzed for CFSE profiles of donor Thy1.1⁺ CD8⁺ cells (Left) and host CD25⁺ FoxP3⁺ CD4⁺ Tregs (Right). (B) Total cell numbers of host CD122^high MP CD8⁺ T cells, CD3^– CD122^high NK1.1⁺ CD49b⁺ NK cells, and CD25⁺ FoxP3⁺ CD4⁺ Tregs in spleens of animals treated as in A. Numbers to the left refer to the amount of IL-2 injected; numbers in histograms represent the percentage of divided (CFSE^low) donor cells. Dashed lines refer to the levels seen in animals treated with 200,000 IU IL-2. Data are representative of four independent experiments.