Pathogenic outcome following experimental infection of sheep with Chlamydia abortus variant strains LLG and POS.
Pathogenic outcome following experimental infection of sheep with Chlamydia abortus variant strains LLG and POS.
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DOI：
10.1371/journal.pone.0177653
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
Longbottom D
中科院分区：
文献类型：
--
作者：
Livingstone M;Wheelhouse N;Ensor H;Rocchi M;Maley S;Aitchison K;Wattegedera S;Wilson K;Sait M;Siarkou V;Vretou E;Entrican G;Dagleish M;Longbottom D
本研究调查了两种流产衣原体菌株（LLG 和 POS）的发病机制，并与已知导致小反刍动物晚期流产的典型野生型菌株（S26/3）进行了比较。三种品系在妊娠中期的挑战导致相似的妊娠结局，大约 50-60% 的母羊发生流产，平均妊娠长度也相似。然而，胎盘病理的严重程度存在差异，LLG 菌株的感染似乎较轻，这反映在产后阴道拭子中脱落的微生物数量较少，胎盘涂片中存在的肉眼病理和微生物较少。 POS 菌株的结果与 LLG 有所不同，观察到感染的局灶性限制更多。流产后抗体反应揭示了变性条件下基本体 (EB) 制剂中存在的主要外膜蛋白 (MOMP) 的血清阳性率存在显着差异，最显着的是抗 LLG 和抗 POS 恢复期血清，其中来自三种菌株的 EB 中没有或减少检测到 MOMP。这些结果以及对整个 EB 和衣原体外膜复合物制剂的额外分析表明，这三种菌株的 MOMP 存在构象差异。总体而言，结果表明，大体胎盘病理学和临床结果并不表明细菌定植和感染的严重程度。结果还强调了 MOMP 表位的潜在构象差异，这可能会影响疾病诊断和新疫苗的开发。
This study investigated the pathogenesis of two variant strains (LLG and POS) of Chlamydia abortus, in comparison to a typical wild-type strain (S26/3) which is known to be responsible for late term abortion in small ruminants. Challenge with the three strains at mid-gestation resulted in similar pregnancy outcomes, with abortion occurring in approximately 50–60% of ewes with the mean gestational lengths also being similar. However, differences were observed in the severity of placental pathology, with infection appearing milder for strain LLG, which was reflected in the lower number of organisms shed in vaginal swabs post-partum and less gross pathology and organisms present in placental smears. Results for strain POS were somewhat different than LLG with a more focal restriction of infection observed. Post-abortion antibody responses revealed prominent differences in seropositivity to the major outer membrane protein (MOMP) present in elementary body (EB) preparations under denaturing conditions, most notably with anti-LLG and anti-POS convalescent sera where there was no or reduced detection of MOMP present in EBs derived from the three strains. These results and additional analysis of whole EB and chlamydial outer membrane complex preparations suggest that there are conformational differences in MOMP for the three strains. Overall, the results suggest that gross placental pathology and clinical outcome is not indicative of bacterial colonization and the severity of infection. The results also highlight potential conformational differences in MOMP epitopes that perhaps impact on disease diagnosis and the development of new vaccines.