CD40是由277氨基酸组成的膜着糖蛋白,在B淋巴细胞、上皮细胞及某些肿瘤细胞株中表达,为B淋巴细胞分化抗原,在细胞间粘着、细胞增殖与分化、蛋白质酪氨酸磷酸化等方面发挥重要作用。其分子克隆表明,CD40与肿瘤坏死因子受体(TNFR)有较高同源性(39.5%)。根据北京放射医学研究所贺福初等提出的“细胞因子与受体的协同进化规律”(2ndInt.Congr.on Cytokines.A14,Mar.23—26,1992,Florence,Italy),预测“CD40配基(CD40L)与TNF同源、且同源性程度接近 CD40 is a membrane glycoprotein composed of 277 amino acids, which is expressed in B lymphocytes, epithelial cells and some tumor cell lines. It is an antigen of B lymphocyte differentiation, intercellular adhesion, cell proliferation and differentiation, and protein tyrosine phosphate Etc. play an important role. Its molecular cloning showed that CD40 has high homology (39.5%) with tumor necrosis factor receptor (TNFR). According to the ”Law of Co-evolution of Cytokines and Receptors" proposed by He Fuchu, Beijing Institute of Radiation Medicine (2ndInt.Congr.on Cytokines.A14, Mar. 23-26, 1992, Florence, Italy) CD40 ligand (CD40L) is homologous to TNF and has a similar degree of homology