中文摘要：

目的制备B族链球菌（GBS）表面免疫原性蛋白（Sip）,研究其免疫原性及抗体保护功能,为GBS蛋白疫苗研究奠定基础。方法采用基因重组技术构建表达载体,并表达GP-Sip融合蛋白。用pET-Sip融合蛋白免疫小鼠,并免疫家兔制备多克隆抗体。Western blot检测GP-Sip蛋白特异性,ELISA检测家兔及小鼠血清中特异性抗体水平,调理吞噬试验检测Sip抗血清的功能。结果表达载体经酶切和测序证明构建正确,GP-Sip蛋白在大肠杆菌中以可溶形式表达,纯化后纯度可达90%以上。Western blot显示GP-Sip蛋白可与pET-Sip蛋白的免疫血清发生免疫反应。ELISA显示Sip可诱发小鼠产生高水平的IgG抗体。Sip抗血清具有明显地促进吞噬细胞对GBS的吞噬作用。结论已成功构建GP-Sip表达载体,并高效表达了Sip。该蛋白具有良好的免疫原性,其抗体具有良好保护功能,可作为GBS蛋白疫苗成分或荚膜多糖疫苗载体成分。

英文摘要：

Objective To prepare the surface immunogenic protein（Sip）of group B streptococcus（GBS）,study its immunogencity and function and lay a foundation of development of GBS protein vaccine.Methods Construct expression vector by gene recombination technique and express GP-Sip.Immunize mice and rabbits with previously expressed pET-Sip.Identify the specificity of expressed GP-Sip by Western blot with the antisera of immunized rabbits.Determine the specific antibodies in sera of immunized mice and rabbits by ELISA using the expressed GP-Sip.Determine the function of Sip antiserum by opsonophagocytosis test in mice.Results Expression vector was correctly constructed as proved by restriction analysis and sequencing.GP-Sip was expressed in a soluble form in E.coli,and reached a purity of more than 90% after purification.Western blot showed specific reaction of GP-Sip with antisera against pET-Sip.ELISA proved that Sip induced high serum IgG level in mice.Sip antiserum promoted the phagocytosis of GBS by phagocytes significantly.Conclusion The expression vector for GP-Sip was successfully constructed,and Sip was highly expressed.The expressed product showed good immunogenicity,and its antiserum showed good protection,which might be a candidate component of GBS protein vaccine or vector of capsular polysaccharide vaccine.