Interleukin 11 (IL-11) is a multifunctional cytokine belonging to the IL-6 family, sharing structural homology and signaling pathways with IL-6, oncostatin M, and leukemia inhibitory factor. Primarily secreted by stromal cells, fibroblasts, and osteoblasts, IL-11 exerts pleiotropic effects in hematopoiesis, inflammation, and tissue repair. It promotes the proliferation of hematopoietic stem cells and megakaryocytes, enhancing platelet production. Notably, IL-11 suppresses the proliferation of some cancer cells and induces apoptosis in certain tumor lines by regulating the JAK/STAT and MAPK signaling cascades. Additionally, it modulates inflammatory responses by inhibiting pro-inflammatory cytokine secretion.To test the effect of IL11 on cell proliferation, TF-1 cells were seeded into triplicate wells of 96-well plates and allowed to attach, replaced with various concentrations of recombinant human IL11. After incubated for 72h, cells were observed by inverted microscope and cell proliferation was measured by Cell Counting Kit-8 (CCK-8). Briefly, 10 μl of CCK-8 solution was added to each well of the plate, then the absorbance at 450 nm was measured using a microplate reader after incubating the plate for 1-4 hours at 37 ℃. Cell viability was assessed by CCK-8 assay after incubation with recombinant human IL11 for 72h. The result was shown in Figure 1. It was obvious that IL11 significantly increased cell viability of TF-1 cells. The ED50 of recombinant human IL11 is 0.271 μg/ml.