Clone BVD3-1F9 recognizes the human interleukin-3 (IL-3) antigen, a secreted molecule which belongs to a discrete family of cytokines that regulates the growth, differentiation, migration, and effector function activities of many hematopoietic cells and immunocytes. IL-3 stimulates the differentiation of multipotent hematopoietic stem cells into myeloid progenitor cells or into lymphoid progenitor cells. In addition, IL-3 stimulates proliferation of all cells in the myeloid lineage (granulocytes, monocytes, and dendritic cells), in conjunction with other cytokines. It is secreted by basophils and activated T cells to support growth and differentiation of T cells from the bone marrow in an immune response. Activated T cells can either induce their own proliferation and differentiation, or that of other T cells.