中文摘要：

目的原核表达△A146Ply蛋白，评价△A146Ply黏膜免疫对肺炎链球菌（Streptococcuspneumon—ioe，5．Pn）在宿主鼻咽部定植的保护作用。方法IPTG诱导、Ni—NTA树脂纯化获得纯化的△A146Ply蛋白，经黏膜免疫BALB／C小鼠，制备其特异性抗血清；进行体内抗定植实验，观察小鼠鼻咽部灌洗液和肺部残存的细菌数量，检测△A146Ply黏膜免疫对19F型肺炎链球菌在鼻咽部定植的保护作用。为验证该保护作用是否具有广谱性，培养血清型14型、3型、6型和2型S．pn，经鼻腔感染免疫后小鼠，评价△A146Ply蛋白黏膜免疫对多株肺炎链球菌定植的保护作用。进行体外抗黏附实验，检测△A146Ply蛋白及其抗血清是否对无荚膜的肺炎链球菌R6黏附A549细胞具有抑制作用。结果获得了纯度〉90％的目的蛋白；体内实验结果显示，△A146Ply黏膜免疫可以显著降低肺炎链球菌19F在宿主鼻咽部和肺部残存的细菌数量（P〈0．01）；14型和3型肺炎链球菌在免疫后小鼠鼻咽部及肺部定植的数量均显著下降（P〈0．05），2型肺炎链球菌在免疫后小鼠肺部定植的数量显著下降（P〈0．05），6B型肺炎链球菌在免疫组与对照组小鼠鼻咽部及肺部均无显著差异（P〉0．05）；△A146Ply特异性抗血清△A146Ply蛋白对R6黏附A549细胞的抑制效应呈剂量依赖性。结论△A146Ply蛋白经黏膜免疫BALB／C小鼠可以对多种血清型的肺炎链球菌在宿主鼻咽部及肺部的定植提供显著保护作用，为Ply作为肺炎链球菌疫苗候选蛋白的应用提供了实验依据。

英文摘要：

Objective This study was aimed pression and evaluate intranasal immunization with to obtain △A146Ply protein, by prokaryotic ex- △A146Ply against nasopharyngeal colonization of Streptococcus pneumonia （S. pn） . Methods △A146Ply protein was obtained by induction with IPTG, and purification with Ni-NTA resin. BALB/C mice were intranasally immunized to obtain AA146 Ply specific antiserum. The in vivo anti-colonization of AA146 Ply protein against S. pn serotype 19F was evaluated by the number of surviving bacteria existing in nasopharyngeal washes and lung homogenates. In addition, multiple strains of serotype 14, 3, 6, and 2 were cultured to further determine the protective effect of AA146 Ply by in vitro antidhesion assay in A549 cells. Results △A146Ply protein was obtained with 〉 90% purity. In vivo experiments showed that intranasal immunization with △A146Ply significantly reduced the colonization number of 19F Streptococcus pneumoniae in nasopharynx and lung of hosts （P 〈 0. 01 ） . Colonization of muhiple serotypes 14 and 3 in the nasot）harvnx and lung of immunized mice was significantly decreased compared to control mice （P 〈 0. 05） . Bacteria of serotype 2 colonized in the lung were significantly decreased （P 〈 0. 05） Serotype 6B did not how difference in colonization in both immunized and control mice （P 〉 0. 05） . In vitro anti-adhesion results showed that the inhibition effect of △A146Ply-specific antibody was dose-dependent. Conclusion Intranasal immunization of BALB/C mice with △A146Ply protein could protect hosts against colonization of various Streptococcus pneumoniae serotypes in the nasopharynx as well as lung, suggesting Ply protein as pneumoeoccal vaccine candidate.