CD40LG, also known as CD40 ligand, belongs to the tumor necrosis factor family. This protein binds to TNFRSF5. CD40LG mediates B-cell proliferation in the absence of co-stimulus as well as IgE production in the presence of IL-4. CD40 ligand dysregulation on T cells and antigen presenting cells contributes to the immune deficiency associated with HIV infection and AIDS. Recombinant mouse CD40LG, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.