Background：CD40 is a 48 kD type I glycoprotein also known as BP50. It is a member of the TNFR superfamily primarily expressed on B cells, macrophages, follicular dendritic cells, endothelial cells, fibroblasts, and at low levels on plasma cells. CD40 has been reported to be involved in B cell differentiation, costimulation, isotype class-switching, and protection of B cells from apoptosis. Additionally, CD40 is important for T cell-B cell interactions. The ligand of CD40 is CD154 （CD40 ligand）.
Buffer：0.2 um filtered in PBS, pH7.2. Azide Free （AF）/Low Endotoxin （LE）： Contains no stabilizers or preservatives. Endotoxin level is ＜ 2 EU/mg （ ＜ 0.002EU/ug） as Determined by LAL gel clotting assay.
