新型抗体靶向性核酸转移系统关键组分SPA-PEI交联物的生物学功能研究

目的 考察新型抗体靶向性核酸转移系统的关键组分葡萄球菌A蛋白-聚乙烯亚胺交联物(SPA-PEI)的生物学功能,即结合IgG与压缩、复合DNA的能力.方法 采用酶联免疫吸附试验和中和抑制实验测定SPA-PEI交联物与多种来源IgG的结合能力;采用DNA凝胶阻滞实验测定SPA-PEI交联物与DNA片段的结合;采用溴化乙啶拒掺实验测定SPA-PEI交联物压缩DNA的能力.结果 SPA-PEI交联物可与多种种属来源的IgG良好结合;SPA-PEI交联过程对SPA的结合特性无明显影响,SPA活性保持较好;SPA-PEI交联物能较好地中和质粒DNA或脱氧核酶(DzTi)的负电荷,压缩DNA片段能力接近游离PEI.结论 制备的SPA-PEI交联物保持了SPA和PEI的生物学活性;SPA-PEI交联物可用于抗体靶向性核酸转移系统的构建.

Biological functions of SPA-PEI conjugate as one key component for construction of a novel antibody-targeted DNA delivery system

Objective To investigate the biological function of SPA-PEI conjugate(staphylococcal protein A-polyethyleneimine cross-linker),which is one key component for construction of a novel antibody-targeted DNA delivery system.Methods The binding capacity of SPA-PEI conjugate with multiple sources of IgG was determined by enzyme-linked immunosorbent assay and neutralization inhibition assay.The binding capacity of SPA-PEI conjugate with DNA fragment was determined by DNA gel retardation assay,and its DNA condensing ability was measured by Ethidium bromide exclusion assay.Results SPA-PEI conjugate could bind well to many species-derived IgGs.SPA-PEI conjugate had no significant effect on the binding properties of SPA.SPAPEI conjugate could neutralize negative charges of the plasmid DNA or DzTi.Its DNA condensing ability was nearly same to that of free PEI,which suggested a excellent DNA condensing ability of the SPA-PEI conjugate.Conclusion SPA-PEI cross-linkers prepared by this project group maintained the biological activity of SPA and PEI.SPA-PEI cross-linkers could be used for the construction of a novel antibody-targeted non-virus DNA delivery system.