Molecular cloning and characterization of the genes coding for the highly immunogenic cluster of 90-kilodalton envelope proteins from the Chlamydia psittaci subtype that causes abortion in sheep
Molecular cloning and characterization of the genes coding for the highly immunogenic cluster of 90-kilodalton envelope proteins from the Chlamydia psittaci subtype that causes abortion in sheep
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DOI：
10.1128/iai.66.4.1317-1324.1998
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发表时间：
1998-04-01
影响因子：
3.1
通讯作者：
Herring, AJ
中科院分区：
文献类型：
--
作者：
Longbottom, D;Russell, M;Herring, AJ
如果我们要理解和修改这些生物利用的致病机制，就必须清楚地识别和表征衣原体外膜中参与粘膜上皮细胞感染的蛋白质。我们已经鉴定并分离出一个包含4个基因的家族，这些基因编码推定的外膜蛋白（POMPs）， POMPs是一组约90 kDa的蛋白，存在于导致绵羊内源性流产的热风衣原体亚型（菌株S26/3）的外膜中。这些蛋白虽然成分较少，但却是主要的免疫原，正如用流产后羊血清对衣原体外膜复合物进行免疫印迹所显示的那样，因此是潜在的诊断和/或保护性抗原候选物。用流产后羊血清对其中一个POMPs表达的氨基端和羧基端进行免疫印迹表明，主要的体液免疫反应似乎只针对氨基端。结合使用pomp特异性单克隆抗体对s26 /3感染细胞的阳性免疫荧光染色，提示pomp可能表面定位，更具体地说，是这些蛋白质的氨基末端的表面暴露。4个pomp基因具有高度同源性，相似度为82% ~ 100%（其中2个基因相同），在鹦鹉螺肺炎毒株和猫肺炎毒株中分别检测到强同源基因和弱同源基因。在沙眼衣原体和肺炎衣原体菌株中没有发现pomp同源物，但这并不排除它们的存在。与羊流产衣原体的各种亚型缺乏同源性，这使绵羊流产亚型的诊断复杂化，表明这些90 kda蛋白可能适合作为血清诊断抗原。
Proteins present in the outer membrane of chlamydiae that are involved in mucosal epithelial cell infection must clearly be identified and characterized if we are to understand and modify the pathogenic mechanisms utilized by these organisms. We have identified and isolated a family of four genes encoding putative outer membrane proteins (POMPs), a group of proteins of approximately 90 kDa present in the outer membrane of the subtype of Chlamydia psittaci that causes ovine enzootic abortion (strain S26/3). These proteins, although minor components, are major immunogens, as shown by the immunoblotting of chlamydial outer membrane complexes with postabortion sheep sera, and are therefore potential diagnostic and/or protective antigen candidates, Immunoblotting of the expressed amino-and carboxy-terminal halves of one of the POMPs with postabortion sheep sera showed that the major humoral immune response appeared to be directed solely against the amino-terminal half This result, in combination with the positive immunofluorescence staining of S26/3-infected cells using POMP-specific (specific to the amino terminal half of the proteins) monoclonal antibodies, suggests the probable surface localization of the POMPs and, more specifically, the surface exposure of the amino-terminal half of these proteins. The four pomp genes are highly homologous, sharing 82 to 100% similarity with each other (two of the genes are identical), Genes with strong and weak homologies were also detected in C. psittaci avian and feline pneumonitis strains, respectively. No pomp homologs were found in strains of C. trachomatis and C. pneumoniae, but this does not preclude their existence, The absence of homology with various subtypes of C. pecorum, which complicate the diagnosis of the ovine abortion subtype, indicates the possible suitability of the these 90-kDa proteins as serodiagnostic antigens.