FLT3LG, also known as fms-related tyrosine kinase 3 ligand, is an alpha-cytokine that promotes the differentiation of multiple hematopoietic cell lineages. Also, this protein acts as a growth factor that increases the number of immune cells by activating the hematopoietic progenitors. FLT3LG is crucial for steady-state pDC and cDC development. It controls the development of DCs and is particularly important for plasmacytoid DCs and CD8-positive classical DCs and their CD103-positive tissue counterparts. Recombinant human FLT3LG, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.