Interleukin 3 (IL-3) is encoded by the IL3 gene in humans. It is a biosignal (cytokine) that works as part of the immune system to enhance the body’s innate immune response to disease. It is secreted by basophils and activated T cells and assists in the growth and differentiation of bone marrow-derived T cells in the immune response.IL-3 acts by binding to the IL-3 receptor to stimulate the differentiation of pluripotent hematopoietic stem cells into myeloid progenitors or, together with IL-7, to stimulate the differentiation of pluripotent hematopoietic stem cells into lymphoid progenitors. In addition, IL-3, together with other cytokines such as erythropoietin (EPO), granulocyte macrophage colony-stimulating factor (GM-CSF), and IL-6, stimulates the proliferation of all cells of the myeloid lineage (granulocytes, monocytes, and dendritic cells).