IL-7 binds to HS-27a cells.

Cells in suspension were incubated in PBS containing BTN–IL-7, BTN-Ctrl, or no protein (FITC only), followed by incubation with FITC-avidin. Live cells were gated, as shown in panel A, and analyzed by flow cytometry (B). Neg indicates the position of unstained control cells. (C) Cells were incubated under adherent conditions with BTN–IL-7, the mixture of BTN–IL-7 plus blocking anti–IL-7 antibodies (BTN–IL-7+Ab), or BTN-Ctrl. The cells were incubated with FITC-avidin and washed, and the fluorescence was measured by a fluorescence plate reader. Each bar represents the average ± SD for 4 samples. Nuclei of the cells incubated with BTN–IL-7 or the mixture of BTN–IL-7 plus blocking anti–IL-7 were counterstained with Hoechst dye, and staining of FITC (green) and Hoechst (blue) was visualized by fluorescence microscopy in panel D or E, respectively. Original magnification × 600.