Figure 1.

Pre-assembly of γc Cytokine Receptor Complexes on Mature T Cells

(A) Surface IL-7Rα proteins outnumber γc proteins on naive CD4⁺ T cells. Surface γc, IL-7Rα, and IL-2Rβ proteins were quantified on naive (CD44^lo) Foxp3^– CD4⁺ T cells from Foxp3-EGFP reporter mice. Saturating concentrations of PE-conjugated antibodies and a standard curve generated using Quantum R-PE MESF beads were used to determine the number of receptor number per cell. Bar graphs show summary of three independent experiments with three mice and mean and SEM are shown.

(B) SPR analysis of IL-7Rα binding to γc. Binding sensorgrams (black lines) of IL-7Rα over immobilized γc are displayed and globally fit to a single step kinetic model (red lines) to determine the k_on and k_off rate constants.

(C) Binding sensorgrams of IL-2Rβ over an immobilized γc sensor chip. The inset shows a dose-response curve plotting the maximal responses (R_max, depicted by the dashed boxes) for each IL-2Rβ concentration. The plot of R_max values versus IL-2Rβ concentrations was non-linearly fit to a single-site binding affinity model to determine a K_d value.

See also Figure S1.