IL-3 is a major hematopoietic growth factor produced by basophils and activated T cells and drives the differentiation of hematopoietic stem cells into myeloid lineages precursors. In conjunction with IL-7, IL-3 will induce lymphoid precursor cell differentiation. Together with other cytokines including EPO, GM-CSF, and IL-6 in an immune response, IL-3 will support growth and differentiation of T cells from the bone marrow.