Figure 2: IL-2Rα is critical for the induction of GM-CSF.

(a,b) Sorted naive T_H cells (CD4⁺CD45RO⁻CD25^−/medCD127⁺) were activated (αCD3) in the presence of 10 ng ml⁻¹ of the indicated cytokine for 5 days (n=6). Shown are cumulative results of GM-CSF⁺ in T_H cells (a) and the level of secreted GM-CSF in the cell culture supernatant (b). ND, not detected. (c–e) Naive T_H cells as in a and b were activated (αCD3) in the presence of the indicated concentration of IL-2 for 5 days. Shown are the frequency of GM-CSF⁺ and IFN-γ⁺ T_H cells (c, n=6), GM-CSF levels in the cell culture supernatant (d, n=12) and the frequency of IL-2Rα⁺ T_H cells (e, n=4). (f) GM-CSF levels in serum of healthy individuals was analysed by the enzyme-linked immunosorbent assay (n=99). Data are combined from three independent experiments. (g,h) Representative example (g) and cumulative results (h) of sorted naive T_H cells, which were activated (αCD3) in the presence of 10 ng ml⁻¹ IL-2 and analysed for GM-CSF secretion and IL-2Rα expression on day 5 (n=12). Data are combined from three independent experiments. (i) Blocking of the IL-2Rα by monoclonal antibodies during the activation of naive T_H cells in the presence of 10 ng ml⁻¹ IL-2 for 5 days (n=6). Data are combined from three independent experiments. For all figures error bars show mean±s.e.m.