Fig. 3.

CD4⁺CD25^high T cells from cancer patients and healthy donors exhibit a similar suppressive potential. (a) Sorted CD4⁺CD25^high cells from nine healthy donors and 12 patients with metastatic cancer were cultured with autologous CD4⁺CD25⁻ stimulated with microbeads-conjugated anti-CD3 and anti-CD28 antibodies. T cell proliferation was evaluated using [³H]-thymidine incorporation. Proliferation was determined in triplicate cultures. Inhibition rate of proliferation is expressed as a percentage of co-culture proliferations of 100 000 CD4⁺CD25⁻ with CD4⁺CD25⁺ at a CD4⁺CD25⁻/CD4⁺CD25⁺ ratio of 2 : 1, compared to proliferation of CD4⁺CD25⁻ alone. (b) Sorted CD4⁺CD25^high cells from four representative cancer patients (kidney cancer: two, lung cancer: two) were cultured with autologous CD4⁺CD25⁻ stimulated with anti-CD3 and anti-CD28 microbeads. Similar assay as described in (a).