Interleukin-5 (IL-5), a secreted glycoprotein, is a member of the hematopoietic family. Interleukin 5 has been shown to stimulate the proliferation of TF-1 cells. To test this effect, TF-1 cells were seeded into triplicate wells of 96-well plates at a density of 1x104cells/well and incubated for 48h in the presence or absence of various concentrations of IL-5 at 37oC. The growth of cells were observed by inverted microscope and cell proliferation was measured by Cell Counting Kit-8 (CCK-8). Briefly, 10μL of CCK-8 solution was added to each well of the plate, then measure the absorbance at 450nm using a microplate reader after incubating the plate for 1-4 hours at 37oC.
Cell proliferation of TF-1 cells after incubation with IL-5 for 48h observed by inverted microscope was shown in Figure 1.

The dose-effect curve of IL-5 was shown in Figure 2. It was obvious that it significantly promoted cell proliferation of TF-1 cells. The ED50 for this effect is typically 0.18 to 7.675ng/mL.