鼠TNF-α功能位点及其中和性抗体结合位点研究

The Study of Mouse TNF-α Functional Domain and Its Neutralizing Antibody Binding Site

肿瘤坏死因子TNF-α是一个多功能的细胞因子,许多免疫系统疾病的发生和TNF-α的过量释放有关.对TNF-α的功能研究有助于了解这些疾病的发生机制,而以TNF-α为靶点的抗体可用于治疗多种自身免疫性疾病.通过研究一个抗鼠TNF-α中和性单克隆抗体的结合位点,确定了鼠TNF-α行使其生物学功能的关键部位.首先利用酵母展示技术确定了中和性抗体9C6的结合位点是鼠TNF-α的第29～40氨基酸线性片段.然后在此区域引入点突变,找到鼠TNF-α与9C6抗体结合的关键位点.最终用大肠杆菌表达鼠TNF-α和其突变体蛋白,通过L929细胞杀伤实验,证实与9C6抗体结合的关键位点也是决定鼠TNF-α生物学功能的关键位点.

Tumor necrosis factor alpha（TNF-α） is a multi-functional cytokine that plays a significant role in many autoimmune diseases. The key biological functional domain of mouse TNF-α was determined by identifying the binding site of mouse TNF-α neutralizing antibody 9C6. Using yeast surface display technology, it was determined that 9C6 can recognize the linear amino acid fragment 29-40 of mature mouse TNF-α protein. Through mutagenesis experiments of this TNF-α region, the critical amino acids necessary for 9C6 binding were identified. Finally, wild-type mouse TNF-α and mutant variants that loses binding ability to 9C6 were expressed in Escherichia coli, purified, and used in a L929 cell killing assay. The assay results proved that the key amino acids for 9C6 binding were consistent with mouse TNF-α functional domain.