The CD40 is a type I transgender protein that is transmitted in the immune system's B cells and special antigen to the surface of the cells and many non -hematopoietic cell types and cancer cells. It belongs to the TNF receptor super family.CD40 is expressed in B cells, foam dendritic cells, dendritic cells, activated monocytes, macrophages, endothelial cells, vascular smooth muscle cells, and several tumor cell lines. CD40 interacts with CD40 Ligand (CD40L/TNFSF5).CD40/CD40L is essential for the beginning and progress of cells and body fluid adaptive immunity, and it is an important area of concern in the study of tumor immunology, neurodegeneration, vascular disease and inflammatory diseases.