沙眼衣原体质粒蛋白pORF5生物学特性初步研究

目的 分析沙眼衣原体(Chlamydia trachomatis,Ct)隐蔽性质粒编码的质粒蛋白pORF5在感染细胞中的定位并初步探讨其生物学特征.方法 PCR扩增pORF5质粒蛋白编码基因,构建pORF5原核表达重组体并诱导表达融合蛋白;融合蛋白经Glutathione Sepharose亲和层析纯化后免疫小鼠,制备单克隆抗体和多克隆抗体,间接免疫荧光技术及免疫印迹鉴定抗体的特异性;分析pORF5质粒蛋白在感染细胞中的分布及表达模式特征.采用ELISA分析pORF5质粒蛋白在自然感染状态下的表达情况及免疫原性.结果 pORF5主要分布于宿主细胞质,但也少量分布在原体(EB)和网状体(RB)上,在细胞质中的分布模式与衣原体分泌蛋白酶样活性因子(CPAF)基本相似,激光共聚焦结果显示两者并不重叠;pORF5能与Ct生殖道感染患者血清发生强烈的免疫应答.结论 pORF5为衣原体分泌蛋白,并具有很强的免疫原性;在自然感染状态下,pORF5质粒蛋白基因被激活产生内源性靶蛋白.

Abstract：

Objective To localize and characterize the plasmid protein pORF5 in the Chlamydia trachomatis(Ct) infected cells. Methods The open reading frame encoding for pORF5 protein from the Ct plasmid was amplified and cloned into the pGEX-6p vector. The recombinant plasmid pGEX-pORF5 was transformed into XL1-blue E. coli to express fusion protein with the glutathione-s-transferase (GST). After purified with Glutathione Sepharose 4B beads, the pORF5 fusion protein was used to immunize mice to make monoclonal and polyclonal antibody. The antibodies were used to localize the endogenous pORF5 protein and detect the expression pattern in Chlamydia-infected cells using an indirect immunofluorescence assay (IFA). At the same time, ELISA was used to determine whether pORF5 plasmid protein was expressed and immunogenic during Ct infection in humans. Results pORF5 was detected a dominant signal in the cytosol of the Chlamydia-infected cells with a pattern similar to that of anti-CPAF. pORF5 also appeared in the RBs and EBs in small quantity. Athough pattern was similarly, pORF5 did not overlap with CPAF. pORF5 protein was strongly recognized antiserum in an ELISA. Conclusion The pORF5 plasmid protein was identified as a secreted protein with good immunogenicity, pORF5 gene was to express the endogenous target protein during human infection.

Preliminary study on biological characterization of Chlamydia trachomatis plasmid protein pORF5

Objective To localize and characterize the plasmid protein pORF5 in the Chlamydia trachomatis(Ct) infected cells. Methods The open reading frame encoding for pORF5 protein from the Ct plasmid was amplified and cloned into the pGEX-6p vector. The recombinant plasmid pGEX-pORF5 was transformed into XL1-blue E. coli to express fusion protein with the glutathione-s-transferase (GST). After purified with Glutathione Sepharose 4B beads, the pORF5 fusion protein was used to immunize mice to make monoclonal and polyclonal antibody. The antibodies were used to localize the endogenous pORF5 protein and detect the expression pattern in Chlamydia-infected cells using an indirect immunofluorescence assay (IFA). At the same time, ELISA was used to determine whether pORF5 plasmid protein was expressed and immunogenic during Ct infection in humans. Results pORF5 was detected a dominant signal in the cytosol of the Chlamydia-infected cells with a pattern similar to that of anti-CPAF. pORF5 also appeared in the RBs and EBs in small quantity. Athough pattern was similarly, pORF5 did not overlap with CPAF. pORF5 protein was strongly recognized antiserum in an ELISA. Conclusion The pORF5 plasmid protein was identified as a secreted protein with good immunogenicity, pORF5 gene was to express the endogenous target protein during human infection.