Expression, Purification And Function Analysis Of BAFF Receptor TACI Fusion Protein

The tumor necrosis factor (TNF) family members, B cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) are crucial survival factors for peripheral B cells. Excess of BAFF leads to the development of autoimmune disorders in animal models, and high levels of BAFF have also been detected in the serum of patients with various autoimmune c onditions. Therefore, BAFF-targeting t herapy is a promising approach to treat B cell related autoimmune diseases and tumors.As a high a ffinity receptor of BAFF, TACI fusion protein recognize and bind to BAFF specificity. So TACI fusion proteins can neutralize the redundant BAFF in vivo and control the proliferation and activation of B lymphocyte. Therefore, the proteins may function as a ntagonists to relieve and treat B c ell tumors an d autoimmune diseases.The purpose of this research is to express a nd purify the TACI fusion proteins, and study its biological activities on B cell tumors in vitro.In this study, three subjects were investigated:(1) Expression and purify TACI fusion protein: Genes of TACI were inserted into prokaryotic expression vector pET-32a. Recombinant plasmids were transformed into E. coli strain R osetta. The fusion proteins were induced by IPTG and purified by Ni-affinity column.(2) TACI inhibited the proliferation of B cell lymphoma: Some B cells cancer cells can produce BAFF as an autocrine survival factor. we found that TACI fusion proteins inhibited the proliferation of B cell lymphoma cells by neutralizing BAFF specifically, and the effect was dose-dependent.(3)The mechanisms of TACI inhibited the proliferation of B cell lymphoma cells: TACI fusion proteins blocked the cell cycle of B cell lymphoma cell line, Daudi cell at S phase.The effect was also dose-dependent .